bluuebunny/crossref_metadata_2025 huggingface dataset:
ESTIMATION OF PROLACTIN AND GROWTH HORMONE LEVELS BY POLYACRYLAMIDE DISC ELECTROPHORESIS
Authors: NICOLL C. S. , PARSONS J. A. , FIORINDO R. P. , NICHOLS C. W.
Published: December 2008

A procedure for estimating rat prolactin and growth hormone (somatotrophin, STH), by measuring the optical density of the electrophoretically isolated and stained hormone bands in polyacrylamide gel columns, is described and evaluated. A simple and inexpensive densitometer is also described.

Prolactin levels in adenohypophyses and in medium from pituitary incubates were measured by electrophoresis-densitometry (ED) and by the pigeon crop-sac assay. The two methods showed a high degree of correlation. The validity of the ED method for estimating prolactin levels in adenohypophysial tissue and in incubation medium was demonstrated by comparing the prolactin content of adult male and female and of oestrogen-treated male glands and by experiments in vitro. The female pituitary contained about three times more prolactin than the male and the glands of oestrogen-treated males had levels about the same as those of females. It was also shown that the ED method could be used to demonstrate the inhibitory effects of extract of rat hypothalamic tissue on prolactin secretion in vitro by the rat pituitary. Levels of STH in adult male glands, as measured by this method, were comparable to results obtained by others using immunoassays. Propylthiouracil-induced hypothyroidism depressed the STH and prolactin levels in male rat pituitaries, in agreement with the observations of others. The stainability of the prolactin band in rat adenohypophyses was observed to decrease with time when the glands were stored on dry ice. No such change occurred in the staining characteristics of the STH band. Other aspects of the ED method are discussed, including its precision, efficiency, sensitivity, economy and utility.
RADIOACTIVE INULIN, SULPHATE AND CHLORIDE SPACES AND ELECTROLYTES IN THE THYROID GLAND OF RATS AT DIFFERENT AGES
Authors: CHOW S. Y. , WOODBURY D. M.
Published: December 2008

[14C]Inulin, 35SO42- and 36Cl- spaces, 131I- thyroid: serum (T:S) ratio, histological measurements of follicles and electrolyte content of the thyroid gland were determined in male rats 3–17 weeks of age. The thyroid [14C]inulin space of animals of different ages was not significantly different. The thyroid 35SO42- space, however, varied with age. The youngest rats had the largest 35SO42- space. Histological measurements indicated that in the thyroid follicles the epithelial cells were much thinner and the luminal volume was much larger in the younger rats than in older animals. In the older rats, the 35SO42- space was equal to the sum of [14C]inulin (stromal) and the histologically determined luminal spaces. In the younger animals, although the 35SO42- space was larger than in the older animals, it was still not large enough to equal the sum of the volumes determined by the [14C]inulin and the direct histological measurements of the lumen. This is due to the high colloid content in the follicular lumen of the young rats. The lower thyroid 131I- T:S ratio in younger rats also indicated that the thyroid gland was less active than in older animals. The volume of distribution of thyroid Cl- calculated from the chemically determined data of the plasma and of the thyroid tissue concentrations of rats of different ages was the same as that determined by 36Cl-.
THE INFLUENCE OF PITUITARY HORMONES ON THE RESPONSE OF THE SEBACEOUS GLANDS OF THE MALE RAT TO TESTOSTERONE
Authors: EBLING F. J. , EBLING ERIKA , SKINNER J.
Published: December 2008

Testosterone implants releasing about 0·2 mg./day had no effect on sebum production in hypophysectomized-castrated rats, even though treatment by a similar dose of testosterone has been shown to effect a marked increase in sebaceous activity in rats with intact pituitaries.

A preparation of porcine growth hormone, and a preparation of prolactin (luteotrophin) which had no growth hormone activity, were each capable of fully restoring the response of the sebaceous gland in hypophysectomized male rats to testosterone, though the pituitary hormones had no effect by themselves. The stimulation of sebaceous activity was measured both by the increase in sebum production and by the increased incidence of cell division in the sebaceous glands.

The responses of the preputial glands and seminal vesicles to testosterone were independent of the presence of the pituitary, and were not significantly enhanced by the hypophysial hormones.
THE RENAL HANDLING OF PHOSPHATE IN THYROID DISEASE
Authors: MALAMOS B. , SFIKAKIS P. , PANDOS P.
Published: December 2008

The fasting serum phosphate level, the tubular maximal (Tm) phosphate reabsorption and the mean renal phosphate threshold were measured in 18 hyper- and six hypothyroid patients in comparison with 11 euthyroid control subjects. A significant increase of serum inorganic phosphate, phosphate Tm and of the mean renal phosphate threshold were found in hyperthyroidism. These findings suggest an increased tubular reabsorption of phosphate in hyperthyroidism. Four main possible mechanisms of such a renal handling of phosphate in thyroid disease are briefly mentioned although their acceptance needs more direct proof.
CONVERSION OF PROLIFERATIVE ENDOMETRIUM TO SECRETORY ENDOMETRIUM BY PROGESTERONE IN ORGAN CULTURE
Authors: KOHORN E. I. , TCHAO R.
Published: December 2008

Human proliferative endometrial tissue was maintained in organ culture. Glandular cells in the fragments were stimulated to secrete by adding progesterone to the culture medium—but not by insulin, oestradiol or cortisol; insulin enhanced the effect of progesterone. With progesterone, subnuclear vacuolation appeared in the glandular cells after 2–3 days. As the culture continued, these vacuoles disappeared and secretion into the lumen occurred.
INTERACTION OF GONADAL STEROIDS AND THEIR EFFECT ON SEXUAL BEHAVIOUR IN THE RABBIT
Authors: BEYER C. , VIDAL N. , McDONALD P. G.
Published: December 2008

The effect of progestins on mating and pseudomale behaviour was studied in ovariectomized rabbits receiving 0·5 μg. oestradiol benzoate twice daily. Single injections of 0·5, 1·0 and 2·0 mg. progesterone resulted in a 50, 75 and 100% inhibition of mating behaviour respectively. In all groups maximum inhibition occurred 24 hr. after progesterone treatment. Pseudomale behaviour was also inhibited by progesterone but the response was more variable. Single injections of 8 or 20 mg. 20α-hydroxypregn-4-en-3-one did not produce a significant inhibition of either mating or pseudomale behaviour. The physiological role of these hormones in regulating sexual behaviour is discussed.
THE CONCENTRATION OF PROGESTERONE IN THE PERIPHERAL PLASMA OF THE PREGNANT EWE
Authors: BASSETT J. M. , OXBORROW TANA J. , SMITH I. D. , THORBURN G. D.
Published: December 2008

The progesterone concentration in the peripheral plasma of ewes throughout pregnancy has been determined by a protein-binding method.

Plasma progesterone concentrations during the first 50 days of pregnancy (2–3 ng./ml.) were not significantly higher than peak concentrations during the luteal phase in cycling non-pregnant ewes, but there was no decrease in the concentration 15–20 days after mating as occurs in non-pregnant ewes.

Between 50 and 120 days after mating the plasma progesterone concentration increased steadily to values 2–5 times that found in early pregnancy. These high concentrations were maintained until lambing. A decrease in progesterone concentration during the week preceding lambing was usually, but not always, observed.

Mean plasma progesterone concentrations during the last 50 days of pregnancy in ewes with twins were approximately twice those in ewes with a single foetus.
MAMMOTROPHIC AND PROLACTIN-LIKE EFFECTS OF RAT AND HUMAN PLACENTAE AND AMNIOTIC FLUID
Authors: SHANI J. , ZANBELMAN L. , KHAZEN K. , SULMAN F. G.
Published: December 2008

Mammary development in the rat during pregnancy is a continuous process beginning around the third day of pregnancy. In order to study whether mammogenesis is due to a placental stimulus, mammary development in pregnant rats was compared with that in rats with deciduomata; the latter showed no mammary development. There was no correlation between the state of the mammary gland in the rats with deciduomata and their uterine weight or development. This suggested that the placenta is a primary source of mammary development in the pregnant rat.

Rat placental homogenate, human placental extract and human amniotic fluid had mammotrophic activity in rats primed with oestradiol. The crop sac-stimulating activity of rat placental lactogen was found to be approximately 0·005 i.u. prolactin/mg. dry powder, corresponding to 0·10 i.u. prolactin/placenta. Human placental lactogen (Folrini, 95% pure) contained the equivalent of 3·3 i.u. prolactin/mg., corresponding to about 330–825 i.u./placenta. No crop sac-stimulating activity could be detected in amniotic fluid from rats or women.
RE-EXAMINATION OF THE PRESENCE OF CORTICOSTEROIDS IN TWO CYCLOSTOMES, THE ATLANTIC HAGFISH (MYXINE GLUTINOSA L.) AND THE SEA LAMPREY (PETROMYZON MARINUS L.)
Authors: WEISBART M. , IDLER D. R.
Published: December 2008

Fluorescence analyses and observations of plasma extracts on thin-layer chromatoplates including sulphuric acid chromogens failed to indicate the high concentrations of cortisol and corticosterone in Atlantic hagfish and sea lamprey reported by other workers. Double isotope derivative assays of Atlantic hagfish plasma and sea lamprey plasma failed to provide rigorous proof of the presence of these steroids.

Presumptive adrenocortical tissue from Atlantic hagfish and sea lamprey, incubated with radioactive steroids as precursors, failed to give any transformation to cortisol or corticosterone. However, sea lamprey incubations did produce 17α-hydroxyprogesterone from progesterone. No evidence was found for the presence of 17α-hydroxyprogesterone in microgram quantities in the plasma.

These findings are discussed in relation to previous studies in which high concentrations of cortisol and corticosterone were reported.
THE INTERACTION OF THE LONG-ACTING THYROID STIMULATOR (LATS) WITH THYROID TISSUE IN VITRO
Authors: SMITH B. R.
Published: December 2008

Most of the long-acting thyroid stimulator (LATS)-absorbing activity of human thyroid homogenates was shown to be in a soluble fraction containing several components including thyroglobulin, haemoglobulin and serum proteins. Salt precipitation and gel filtration studies indicated that the absorbing activity was not associated with thyroglobulin of high molecular weight, but with a 4s fraction. This 4s fraction has been shown to contain thyroid specific antigens and these may be important in LATS absorption.
BIOCHEMICAL CHANGES DURING DEVELOPMENT OF MOUSE MAMMARY TISSUE IN ORGAN CULTURE
Authors: MAYNE R. , BARRY J. M.
Published: December 2008

A study has been made of the metabolism of mammary tissue from midpregnant C3H mice in organ culture, with and without the hormones needed to induce lactogenesis in the tissue. Insulin greatly stimulated the uptake of glucose by the tissue, and the formation of labelled carbon dioxide and fatty acids from labelled glucose. The further addition of prolactin and corticosterone had little effect. Without hormones the rates of incorporation of [3H]thymidine into DNA and of [14C]uridine into RNA decreased during culture. Insulin stimulated these rates of incorporation and the further addition of prolactin stimulated them still more. Corticosterone had little effect. The rate of incorporation of [32P]orthophosphate into casein fell during culture without added hormones, while insulin, or insulin plus corticosterone, had little effect on it. Prolactin, however, caused a very marked stimulation in cultures with insulin, which was only slightly increased by the further addition of corticosterone. The stimulation of 32P incorporation due to prolactin was only evident after 12 hr. of culture. Delay in addition of prolactin by 12 hr. did not affect the response. Actinomycin D, cycloheximide and colchicine prevented the action of prolactin; hydroxyurea partly prevented it.
ANTIDIURETIC ACTIVITY AND ULTRASTRUCTURE OF THE TOAD CHOROID PLEXUS
Authors: RODRIGUEZ E. M. , HELLER H.
Published: December 2008

Acetic acid extracts of toad choroid plexuses had an antidiuretic effect in water-loaded ethanol-anaesthetized rats, whose pattern was similar to that produced by toad neural lobe extracts and by arginine vasopressin. The antidiuretic activity of the choroid plexus extracts was completely abolished by treatment with sodium thioglycollate. Antidiuretic activity per milligram choroid plexus was about four times higher in the plexus of the third ventricle than in the plexus of the fourth ventricle. The antidiuretic activity of both choroid plexuses increased progressively during the summer and autumn and reached its peak in October; it then fell to very low or undetectable levels during the middle of the winter and spring.

The choroid plexuses also showed seasonal variations in their ultrastructural organization, which might be related to the seasonal variations of their antidiuretic activity.

The origin of the substance(s) responsible for the antidiuretic activity in the choroid plexuses is discussed.
THYROID FUNCTION IN PROTEIN-DEPLETED RATS
Authors: FLORSHEIM W. H. , SUHR BIRUTA Z. , MIRISE R. T. , WILLIAMS A. D.
Published: December 2008

Renal iodide clearance in rats was reduced rapidly when the animals were fed a protein-depletion diet. If the iodine content of the protein-depletion diet is high, this results in an increase in the serum iodide levels to concentrations in excess of 150 μg./100 ml. Protein-bound iodine was elevated due to the accumulation of iodinated serum albumin. Thyroid hormonal iodoamino acid content was transiently depressed, presumably by the mechanism described by Wolff & Chaikoff (1948). Thyroxine metabolism was not affected except for a change in the partition of thyroxine between liver and serum. There was no evidence for pituitary involvement in the effects of protein depletion on thyroid function.
URINARY EXCRETION OF LUTEINIZING HORMONE IN BOYS AND ADULT MEN
Authors: SCIARRA N. , LEONE U.
Published: December 2008

The daily urinary excretion of luteinizing hormone (LH) was determined in 15 boys, aged 5–11 yr., and in 15 adult men, aged 18–65 yr., by an immunological method using the haemagglutination inhibition system.

The hormone was detected in every subject investigated. The mean value for urinary LH excretion in boys was equivalent to 3·4 i.u./24 hr. (range 1·3–6·5) and was 29·3 i.u./24 hr. in adults (range 15·4–44·6). The mean adult: child ratio was 8·6.

There was a significant increase in LH output with age in both the boys and the men; the rate of this increase was the same in both groups. However, there was a sharp rise in hormone output at about the onset of puberty.
THE RESPONSE OF PLASMA INSULIN, GLUCOSE AND NON-ESTERIFIED FATTY ACIDS TO VARIOUS HORMONES, NUTRIENTS AND DRUGS IN THE DOMESTIC FOWL
Authors: LANGSLOW D. R. , BUTLER E. J. , HALES C. N. , PEARSON A. W.
Published: December 2008

The relationships between plasma insulin, glucose, non-esterified fatty acid (NEFA) and α-amino nitrogen concentrations in the domestic fowl have been studied. During a 72-hr. fast the plasma glucose concentration fell while the NEFA concentration rose but there was no change in plasma insulin concentration. Both oral and intracardiac glucose increased the plasma insulin concentration and lowered the plasma NEFA and α-amino nitrogen concentrations. Oral amino acids increased plasma insulin and glucose concentrations but had no effect on plasma NEFA. Intracardiac ox insulin depressed plasma glucose and α-amino nitrogen and increased the plasma NEFA concentration. Intracardiac glucagon increased both plasma glucose and NEFA and depressed the plasma α-amino nitrogen concentrations but had no significant effect on plasma insulin. Intracardiac adrenaline had no effect on plasma NEFA but increased plasma glucose concentration and caused a small depression in plasma insulin concentration.
THE BLOOD LEVELS OF OXYTOCIN DURING MACHINE MILKING IN COWS WITH SOME OBSERVATIONS ON ITS HALF-LIFE IN THE CIRCULATION
Authors: CLEVERLEY JACQUELINE D. , FOLLEY S. J.
Published: December 2008

Blood oxytocin was assayed on the lactating guinea-pig mammary gland.

Transient release of oxytocin was detected in the range of 9–889 μu./ml. plasma in the external jugular vein blood of cows during machine milking. In 24 experiments oxytocin was detected in 17; in nine of these, hormone release by conditional reflex was obtained in response to auditory or visual stimuli associated with the milking routine. All stimuli associated with the milking routine caused oxytocin release. There was no difference in the plasma concentrations detected in response to conditional and nonconditional stimuli. In this and previous work no release of oxytocin was detected in 32% of experimental machine milkings although in most cases milk yields were normal.

Milk ejection was accompanied by increases in intramammary pressure from 12·5–24 mm. to 23–44 mm. Hg; the pressure after ejection was maintained virtually constant for over 1 hr. There was no initial drop in pressure, associated with a neural segmental reflex. Rise in intramammary pressure accompanied the detection of oxytocin in jugular blood in four out of seven experiments. The pressure changes and latency could be simulated by rapid intravenous injection of 100 m-u. synthetic oxytocin. The half-life of synthetic oxytocin in the circulation was 127 ± 9·3 sec. (range 85–164 sec.).
STUDIES ON THE BIOSYNTHESIS OF ALDOSTERONE USING THE SHEEP ADRENAL TRANSPLANT: EFFECT OF SODIUM DEPLETION ON THE CONVERSION OF CORTICOSTERONE TO ALDOSTERONE
Authors: BLAIR-WEST J. R. , BRODIE A. , COGHLAN J. P. , DENTON D. A. , FLOOD C. , GODING J. R. , SCOGGINS B. A. , TAIT J. F. , TAIT S. A. S. , WINTOUR E M. , WRIGHT R. D.
Published: December 2008

The effect of sodium depletion on the conversion of corticosterone to aldosterone has been examined in vivo using the adrenal transplants of two sheep. [3H]Corticosterone was infused continuously directly into the adrenal gland via the carotid artery over a period of 30 min. and the total adrenal effluent was collected via the jugular vein in six consecutive 5-min. samples. The conversion of [3H]corticosterone to [3H]aldosterone and the endogenous output of aldosterone was measured in each sample using a double isotope derivative method and the specific activity of the aldosterone calculated. Radioactive conversion of B → aldosterone reached equilibrium within 10 min. of the start of infusion and remained constant over a period of 10–25 min. Aldosterone secretion was also constant during the first 25 min. of infusion.

In the same sheep the mean percentage conversion increased as aldosterone secretion rose over a range of 2–12 μg./hr. With more severe sodium depletion, i.e. with aldosterone secretion rates of 12–16 μg./hr., conversion decreased to that found in the sodium replete state. The specific activity of the aldosterone was constant throughout the mildly deplete range (2–12 μg./hr.) but fell with severe sodium depletion. In the sodium replete range (0–2 μg./hr.) before the introduction of a parotid fistula, the specific activity was the same as in the mildly deplete state. After the introduction of a parotid fistula the specific activity increased as the secretion decreased from 2 to 0 μg.

The validity of the approach and interpretation of the results in terms of the biosynthetic pathways involved are discussed.
OOCYTE SURVIVAL IN THE MOUSE OVARY AFTER TREATMENT WITH 9,10-DIMETHYL-1,2-BENZANTHRACENE
Authors: KRARUP T.
Published: December 2008

The induction of ovarian tumours in mice by 9,10-dimethyl-1,2-benzanthracene (DMBA) is preceded by the disappearance of oocytes and follicles.

The effect of DMBA on the oocyte population was determined in immature and in mature mice by performing total and differential oocyte counts at different intervals after oral and intraperitoneal administrations of the carcinogen.

In orally treated animals the number of small oocytes was quickly reduced followed by a decrease in the number of growing and large oocytes; in addition, in intraperitoneally treated animals, some growing and large oocytes were directly destroyed.

The sensitivity of the germ cells to DMBA was independent of the age of the animals.

In normal mice, as well as in immature mice treated with DMBA, the number of small oocytes determined the proportion which was stimulated to develop into growing and large oocytes.
THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR OXYTOCIN: SENSITIVITY OF THE ASSAY IN AQUEOUS BUFFER SOLUTION, SPECIFICITY AND THE DISSOCIATION OF IMMUNOLOGICAL AND BIOLOGICAL ACTIVITY
Authors: CHARD T. , FORSLING M. L. , JAMES M. A. R. , KITAU M. J. , LANDON J.
Published: December 2008

A radioimmunoassay for oxytocin in aqueous solution is described, with a sensitivity comparable with the best current bioassays. It is highly specific; arginine-vasopressin and lysine-vasopressin interfere only at 1000-fold greater concentration, while bradykinin, histamine, acetycholine and many other substances, which interfere with some bioassays, have no effect. In certain circumstances, there is a dissociation between loss of biological and immunological activity. Thus reducing agents had no effect on immunological activity, in contrast to their effect on biological activity. In late pregnancy plasma, the biological activity of oxytocin is destroyed more rapidly than the immunological activity. Radioimmunoassays have considerable advantages over bioassays both in convenience and specificity. However, bioassays should be employed for reference purposes because of the dissociation between biological and immunological activity that may occur.
THE ROLE OF THE DORSAL TRACTS OF THE SPINAL CORD AND OF THE MESENCEPHALIC AND THALAMIC LEMNISCAL SYSTEM IN THE MILK-EJECTION REFLEX DURING MILKING IN THE EWE
Authors: RICHARD PH. , URBAN I. , DENAMUR R.
Published: December 2008

The milk-ejection reflex after different lesions of the sensory system was studied by mechanical milking of the ewe. Only animals with lesions which did not produce locomotor ataxia were investigated. Section of the dorsal tract of the spinal cord at different thoracic levels blocked the milk-ejection reflex. This was not due to postoperative shock, because the same type of lesion made at the sacral level was without effect. Moreover, unilateral section of this tract blocked the reflex when milking was limited to the ipsilateral mammary gland. At the cervical level, the interruption of the dorsal tract was ineffective, which can probably be explained by the existence, in sheep, of the spino-cervico-thalamic tract. The latter becomes ventral at the cervical level. Lesions of the lemniscal system in the mesencephalon (bilateral coagulation of the medial lemniscus) and in the thalamus (bilateral destruction of the ventral posterolateral nucleus) do not inhibit the milk-ejection reflex.

The role of the spinal lemniscal system is discussed in relation to the work of others and to the electrophysiological results obtained by one of us. It is suggested that two sensory systems (lemniscal and extralemniscal) have to interact to induce the release of oxytocin evoked by the stimuli of mammary origin during milking.
INCREASE IN PLASMA GROWTH HORMONE CONCENTRATION IN MAN AFTER INFUSION OF ADRENALINE-PROPRANOLOL
Authors: MASSARA F. , STRUMIA E.
Published: December 2008

Plasma human growth hormone (HGH) concentrations were compared during four tests in which 0·9% NaCl solution only, propranolol, adrenaline or propranolol plus adrenaline were infused into six healthy volunteers. In five subjects, HGH levels during the infusion of saline, propranolol or adrenaline showed no significant increase and were virtually identical. During the test with propranolol plus adrenaline, however, there was an increase after adrenaline in spite of concomitant hyperglycaemia. The sixth volunteer showed a wide range of apparently spontaneous and irregular variations in HGH values throughout each of the four tests.

These findings support the view that α-receptors stimulate and β-receptors depress HGH secretion, and show that adrenergically stimulated HGH secretion in man is not inhibited by hyperglycaemia.
THE ADENOHYPOPHYSIS OF FEMALE RATS AFTER HYPOTHALAMIC OESTRADIOL IMPLANTS: AN ELECTRON MICROSCOPIC STUDY
Authors: ZAMBRANO D. , DEIS R. P.
Published: December 2008

The ultrastructural effect of oestradiol implants into the hypothalamus on the adenohypophysis of adult female rats was studied. The main results are the demonstration that mammotrophs or prolactin cells, and to a lesser extent somatotrophs, increased their secretory activity after bilateral implants into the median eminence and arcuate nuclei; in the periventricular area the reaction was weaker and in the anterior hypothalamus the response was negative. In animals with implants in the basal tuberal region, mammotrophs showed an asynchronous secretory activity. Mitosis has been found to occur in fully differentiated mammotrophs, a finding which can be correlated with the increased number of such cells after basal tuberal implants. The gonadotrophs appeared to be atrophied.
EFFECT OF CORTICOTROPHIN AND CORTICOSTEROIDS ON OESTRUS, OVULATION AND OESTROGEN EXCRETION IN THE SOW
Authors: LIPTRAP R. M.
Published: December 2008

Corticotrophin (ACTH), hydrocortisone or prednisolone trimethylacetate were administered daily to sows from 24 hr. before oestrus or from day 14 of the cycle until the end of oestrus. Treatment beginning on day 14 delayed the peak in urinary oestrogen excretion normally seen, postponed the onset of oestrus by 1–3 days and shortened the duration of oestrus. Treatment begun before oestrus did not appear to alter the pattern of oestrogen excretion but shortened the duration of oestrus. Administration of ACTH, but not that of corticosteroids, also interfered with ovulation.
THE RATES OF PLASMA CORTISOL ENTRY AND CLEARANCE IN SHEEP BEFORE AND DURING THEIR EXPOSURE TO A COLD, WET ENVIRONMENT
Authors: PANARETTO B. A. , VICKERY MARION R.
Published: December 2008

Plasma cortisol concentrations and entry rates increased greatly when nine shorn sheep were exposed to cold, wet conditions for periods up to 70 hr. The average entry rate in four of the cold-stressed animals before their rectal temperatures began to fall was 25 μg./min., approximately three to four times greater than in the same sheep before exposure (7·7 μg./min.). The metabolic clearance rates at this time remained unchanged. Plasma cortisol concentration began to increase about 2–3 hr. before the sheeps' rectal temperatures began to fall. The increase continued until concentrations of 100–200 μg./1. were reached after the sheeps' rectal temperature had fallen. Cortisol entry increased at this time to what may probably be maximal or near maximal rates in the sheep (about 150–200 μg./min.). Lowered clearance did not appear to contribute substantially to increased plasma cortisol concentrations at rectal temperatures above 34°. Since clearance rates did not begin to fall rapidly until rectal temperature fell below about 34°, cortisol entry during the terminal phase of hypothermia, approximately 76 μg./min., was very much less than the observed maximum and the high plasma cortisol concentrations measured during this period were residual and sustained by lowered clearance rates.

The adrenal cortices and livers of the sheep after severe hypothermia were heavily infiltrated with fat.

The effects of shearing alone, studied in a separate experiment, had a transitory effect since plasma cortisol concentrations and entry rates had returned to near their pre-shearing levels by about 27 hr.
CARBON DIOXIDE PRODUCTION BY MOUSE BLASTOCYSTS DURING LACTATIONAL DELAY OF IMPLANTATION OR AFTER OVARIECTOMY
Authors: MENKE TERESA M. , McLAREN ANNE
Published: December 2008

The rate of CO2 production by 8-cell embryos (2½ days post coitum) and blastocysts (3½ days post coitum) was measured in mice of the Q strain. The values for blastocysts resembled those obtained by Brinster (1967) in the Swiss strain, both in mean and variance; the values for 8-cell eggs differed in both respects from those obtained by Brinster.

Blastocysts in delay of implantation during lactation or after ovariectomy gave off less CO2 per hr. than either 3½-day blastocysts from normal pregnancies or blastocysts from post-partum matings when the litters were removed at birth. This indicates that blastocysts enter a state of metabolic dormancy during delay of implantation.

When ovariectomized pregnant mice were maintained on 0·5 mg. progesterone per day, their blastocysts produced even less CO2/hr. than those from ovariectomized animals not given exogenous hormone. The implications of this finding are considered with respect to the role of progesterone in delay of implantation.
THE EFFECTS OF OESTROGEN AND PROGESTERONE ON THE SODIUM AND POTASSIUM CONCENTRATIONS OF RAT UTERINE FLUID
Authors: CLEMETSON C. A. B. , MALLIKARJUNESWARA V. R. , MOSHFEGHI M. M. , CARR J. J. , WILDS J. H.
Published: December 2008

Studies of the electrolyte concentrations of uterine fluid samples from spayed rats, after injection of ovarian hormones, showed a much higher potassium concentration after treatment with oestrogen (42·3 m-equiv./1.) than with progesterone (20·8 m-equiv./1.). There was an even more pronounced change in the sodium: potassium ratio, which fell from 7·3 to 1 with progesterone to 2·5 to 1 with oestrogen. These findings are supported by recalculation of the results of Heap & Lamming (1962).

It is suggested that these changes in the Na+ and K+ concentrations of uterine fluid produce changes in the membrane potential of the endometrium which could account for delayed implantation of the negatively charged blastocyst under progesterone dominance and implantation under oestrogen dominance.
PATTERNS OF STEROID BIOSYNTHESIS BY HUMAN ADRENALS INCUBATED IN VITRO WITH [7α-3H]PREGNENOLONE: CHANGES WITH (a) GESTATIONAL AGE, (b) INCUBATION PERIOD AND (c) WEIGHT OF INCUBATED TISSUE
Authors: MILNER A. JOSEPHINE , MILLS I. H.
Published: December 2008

Human adrenal tissue was sliced and incubated with 25 μc [7α-3H]-pregnenolone. The percentage conversion of radioactive precursor to dehydroepiandrosterone (DHA), DHA sulphate, androstenedione, 11β-hydroxyandrostenedione, cortisol and 11-deoxycortisol was estimated by the reverse isotope dilution technique. Incubations of both adult and foetal adrenal slices gave reproducible results. The duration of the incubation period was an important factor affecting the pattern of radioactive steroids synthesized, the adult adrenal pattern being dissimilar to that of the foetal adrenal. A direct proportional relationship between the weight of the incubated tissue and the biosynthesis of cortisol from exogenous [7α-3H]-pregnenolone was not established.

The production of DHA sulphate relative to free DHA increased markedly from 12 to 27 weeks gestation. When incubated for 2 hr. the combined production of DHA and DHA sulphate relative to cortisol and androstenedione decreased with gestational age. There was evidence for considerable 3β-hydroxysteroid dehydrogenase activity in foetal adrenals at 12 to 27 weeks gestation.
THE EFFECT OF NEUROHYPOPHYSIAL HORMONES ON THE AMPHIBIAN OVIDUCT IN VITRO, WITH SOME REMARKS ON THE HISTOLOGY OF THIS ORGAN
Authors: HELLER H. , FERRERI ELENA , LEATHERS D. H. G.
Published: December 2008

The effect of neurohypophysial hormones has been tested in vitro on oviducts of four species of urodele and three species of anuran Amphibia. Contractile responses were obtained with all the hormones used but 8-arginine oxytocin (vasotocin) was usually most potent. The sensitivity of the oviducts varied widely from species to species; there were also pronounced seasonal differences within a species. Histological investigations yielded some information on the abundance and arrangement of muscle fibres in amphibian oviducts. A simple and sensitive (magnification up to × 1000) recording system for isotonic contractions is described.
THYROID FUNCTION AND STEROID HORMONE EXCRETION
Authors: MILLER H. , DURANT J. A. , COWAN JOYCE M. , KNOTT J. M. S. , GARNETT E. S.
Published: December 2008

The excretion of steroid hormone metabolites was studied in normal, thyrotoxic and myxoedematous subjects. Corticosteroid excretion was increased in thyrotoxicosis and reduced in myxoedema.

In myxoedema there was also a fall of total androgen excretion due principally to a reduction of the androsterone component.

There was no change in total androgen excretion in thyrotoxic subjects, but there was a fall of aetiocholanolone excretion.
THE RESPONSE OF THE SEBACEOUS GLANDS OF HYPOPHYSECTOMIZED—CASTRATED MALE RATS TO ADRENOCORTICOTROPHIC HORMONE AND TO TESTOSTERONE
Authors: EBLING F. J. , EBLING ERIKA , SKINNER J. , WHITE AUDREY
Published: December 2008

Administration of 1 i.u./24h of adrenocorticotrophic hormone (Cortrophin ZN, ACTH) to hypophysectomized—castrated rats significantly increased sebum production to the level of that in castrated rats with intact pituitaries. The incidence of mitoses in the sebaceous glands was also significantly increased. Neither the preputial glands nor the seminal vesicles showed any response.

No significant increase in sebum production in hypophysectomized—castrated rats could be detected 24 days after giving implants releasing 0·2 or 0·6 mg testosterone/24 h, although sebaceous mitoses were significantly increased in both instances. Concomitant administration of both ACTH and testosterone raised sebum production to the same extent as ACTH alone, and raised the incidence of sebaceous mitoses to a level equal to that produced by ACTH plus testosterone.

It is concluded that the sebaceous glands respond—either directly or indirectly as the result of stimulation of the adrenal cortex—to ACTH and that this response is less dependent on the presence of the pituitary than is the action of testosterone. ACTH does not itself facilitate the response of the sebaceous glands to testosterone.
RNA SYNTHESIS IN THE RAT ANTERIOR HYPOTHALAMUS AND PITUITARY: RELATION TO NEONATAL ANDROGEN AND THE OESTROUS CYCLE
Authors: SALAMAN D. F.
Published: December 2008

RNA from the anterior hypothalamus and anterior pituitary of rats has been labelled by incubation in vitro with [3H]uridine and characterized by density gradient centrifugation. A study of normal females during the oestrous cycle showed cyclic changes in [3H]uridine incorporation into rapidly labelled RNA (rl-RNA) both in the anterior pituitary and hypothalamus. In both tissues the specific activity of RNA was low at dioestrus and high at oestrus and metoestrus. In androgenized females, incorporation into hypothalamic rl-RNA was less than the oestrus—metoestrus level and similar to that at dioestrus, while incorporation into anterior pituitary rl-RNA was similar to the oestrus—metoestrus level and greater than at dioestrus. [3H]Uridine incorporation into ribosomal RNA (r-RNA) of anterior hypothalamus and pituitary was also demonstrated by incubation for 4 h. Under these conditions there was no effect of androgenization on hypothalamic r-RNA, but the specific activity of pituitary r-RNA was greater than normal.
EXCRETION OF ANTIDIURETIC ACTIVITY IN THE URINE OF CATS AND RATS AFTER ADMINISTRATION OF THE SYNTHETIC HORMONOGEN, Nα-GLYCYL-GLYCYL-GLYCYL-[8-LYSINE]-VASOPRESSIN (TRIGLYCYLVASOPRESSIN)
Authors: KYNČL J. , RUDINGER J.
Published: December 2008

The rate of excretion of antidiuretic activity in the urine of anaesthetized, water-loaded cats and of rats with familial diabetes insipidus after injection of single doses of lysine vasopressin (LVP) and of the long-acting analogue Nα-glycyl-glycyl-glycyl-[8-lysine]-vasopressin (triglycylvasopressin) has been studied by assays in water-loaded rats.

The excreted antidiuretic material in all experiments resembled LVP and differed from triglycylvasopressin in the time course of the recorded response, the slope of the log dose—response relationship, and the index of persistence. The total antidiuretic activity excreted was a fraction of that of the injected LVP but equalled or exceeded the assayable activity of the dose of triglycylvasopressin injected.

It is concluded that the excreted antidiuretic activity is due to LVP and that the excreted hormone originates from the triglycylvasopressin by enzymic activation in vivo.
TISSUE DISTRIBUTION OF CALCITONIN IN THE RAT: COMPARISON WITH PARATHYROID HORMONE
Authors: de LUISE M. , MARTIN T. J. , MELICK R. A.
Published: December 2008

When [125I]calcitonin was injected intravenously into rats the major site of accumulation of radioactivity was the liver, whereas [125I]parathyroid hormone was localized chiefly in the kidney.

The distribution of [125I]bovine serum albumin and of Na [125I] was studied for comparison. Although most of the radioactivity of [125I]calcitonin was found in the soluble fractions of liver and kidney, significant binding to liver microsomes occurred. This fraction also bound an appreciable amount of the radioactivity of [125I]parathyroid hormone. The uptake of [125I]calcitonin by liver could be inhibited by the simultaneous injection of unlabelled calcitonin, but not by that of parathyroid hormone, insulin or adrenocorticotrophic hormone.

These results indicate a role for the liver and kidney in the early clearance of calcitonin and parathyroid hormone respectively. It is likely that the liver is the major site of the metabolism of calcitonin in vivo.
THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR OXYTOCIN: THE EXTRACTION OF OXYTOCIN FROM PLASMA, AND ITS MEASUREMENT DURING PARTURITION IN HUMAN AND GOAT BLOOD
Authors: CHARD T. , BOYD N. R. H. , FORSLING M. L. , McNEILLY A. S. , LANDON J.
Published: December 2008

A method is described for the extraction and concentration of oxytocin from plasma which is simpler and more rapid than other available procedures. It has proved satisfactory for both radioimmunoassay and bioassay of circulating oxytocin. The recovery of added oxytocin was 60 ± 5·5% and showed no significant variation between plasma from pregnant and non-pregnant women, or plasma from other species. The sensitivity of the assay is related to the volume of plasma extracted. With a 10 ml plasma sample and the radioimmunoassay method described previously, the maximum sensitivity under optimal conditions is 0·75 μu. (1·5pg)/ml. In the second stage of human labour, oxytocin is not detectable in maternal plasma at this level of sensitivity. Of 36 cord venous plasma samples studied, 15 showed positive results in the range 1·5–20 μu. (3–40 pg)/ml; of 16 simultaneous cord arterial and venous plasmas, 12 showed positive results; the arterial samples showed a range of 8–145 μu. (7–290 pg)/ml with an average of 45 μu./ml; the venous samples showed a range of 0–100 μu. (0–200 pg)/ml with an average of 24 μu./ml. Plasma oxytocin levels during the second stage of labour in the goat averaged 120 μu. (240 pg)/ml by radioimmunoassay and 100 μu. (200 pg)/ml by bioassay. The half-life of infused oxytocin in the non-pregnant human subject as determined by radioimmunoassay was 5 min.
MAINTENANCE OF PREGNANCY RELATIVE TO THE PRESENCE OF FEW EMBRYOS IN THE RABBIT
Authors: ADAMS C. E.
Published: December 2008

Either one or two 60-h morulae were transferred to one uterine horn of Polish, Dutch or Strain A rabbits in which the mean number of ovulations was 4·3, 6·4 and 10·8. The pregnancy rate, as determined by palpation on day 10, varied from 45–65% (mean 53%) in recipients of one egg to 69–71% with two eggs. Only 20% of the does carrying one foetus maintained pregnancy to term compared with 87% of those with two implants. If pregnancy failed this usually occurred between days 15 and 20. In a further experiment, in which additional eggs were transferred to the contralateral horn, it was shown that all single conceptuses were inherently capable of surviving to term.

It is concluded that irrespective of breed and ovulation rate, two conceptuses are normally required to prevent regression of corpora lutea on about day 17. Treatment with follicle-stimulating hormone in mid-pregnancy or removal of the barren uterine horn on day 13 failed to maintain pregnancies involving only one conceptus.
THE EFFECT OF AUTONOMIC BLOCKING AGENTS ON VASOPRESSIN RELEASE IN VIVO INDUCED BY OSMORECEPTOR STIMULATION
Authors: BRIDGES T. E. , THORN N. A.
Published: December 2008

Intracarotid injection of 0·25 ml of a hyperosmotic (1 m) sodium chloride solution into hydrated rats was an effective stimulus for vasopressin release. The effects of autonomic blocking drugs on this stimulus and on the release of vasopressin by intracarotid injections of acetylcholine were studied.

Anti-adrenergic compounds (reserpine and phenoxybenzamine), ganglion-blocking agents (pempidine and pentolinium) and atropine were shown to be effective in preventing the vasopressin release caused by hyperosmotic stimulation.

Acetylcholine-induced release of vasopressin was inhibited by pempidine but not reserpine.

Based on these findings the nervous pathway(s) involved in the release of vasopressin induced by hyperosmolarity of the plasma is discussed.
EFFECTS OF ANDROGENS AND PROLACTIN ON THE RATE OF PRODUCTION AND COMPOSITION OF SEBUM IN HYPOPHYS-ECTOMIZED FEMALE RATS
Authors: NIKKARI T. , VALAVAARA M.
Published: December 2008

The effect of five androgens on the activity of the sebaceous glands of female rats hypophysectomized at 3–4 weeks of age was studied by determining the rate of production and palmitate: stearate ratio of the skin surface lipids. Both of these values reflected the stimulation of the sebaceous glands by androgens, but the palmitate: stearate ratio appeared to be a more sensitive index of low androgenic activity than the production rate. The response of the sebaceous glands to the androgens tested increased in the order (the relative potencies were calculated from the palmitate: stearate ratios): androstenedione, 17; dehydroepiandrosterone, 33; androstanolone, 48; androstanediol, 91; and testosterone propionate, 100. Prolactin did not enhance the stimulation of the sebaceous glands induced by testosterone propionate.
GENETIC VARIATION IN ADRENAL STRUCTURE: QUANTITATIVE MEASUREMENTS ON THE CORTEX AND MEDULLA IN HYBRID MICE
Authors: SHIRE J. G. M.
Published: December 2008

The volumes of the adrenal cortex and medulla were measured for young adult male mice from the A/Cam and CBA/FaCam strains and from five hybrid generations produced by crossing these inbred strains. The hybrid stocks were the reciprocal F1's, the F2 and the backcrosses to both parental strains. Two independent sets of measurements were made. The second set confirmed and extended the results of the first. Both the adrenal cortex and the adrenal medulla were significantly larger in the CBA mice than they were in the A mice. It seems likely that the observed difference between the strains in cortical volume was determined by genetic variation either at a single locus or, at most, at two loci. The difference in medullary volume was determined by variation at at least two gene loci. In all cases the alleles found in the CBA mice showed dominance. The problems of deciding whether four separate loci were involved or whether all the differences were due to pleiotropic effects of fewer genes is discussed. In the first experiment measurements of the volume and number of cells in the zona fasciculata were made in addition to those of medullary and cortical volume. These measurements confirmed the existence of genetic variation in these characters which had been suggested by earlier findings of significant strain differences in them. The results of the second experiment also showed that the significant strain difference between A and CBA mice in testis weight was brought about by genes other than those causing the adrenal differences.

The relation between the differences in adrenal structure described in this paper and those known to exist between these two strains in other aspects of the adrenal glands and in their target organs are discussed, as is the relation between findings on inbred strains and those to be expected in natural populations.
THE EFFECT OF EXOGENOUS PROGESTAGEN ON THE LEVELS OF FREE OESTROGEN IN THE OVARIAN VEIN PLASMA OF THE EWE
Authors: SMITH J. F. , ROBINSON T. J.
Published: December 2008

The levels of free oestrogen (oestrone and oestradiol-17β) in plasma in the ovarian vein were determined in three groups, each of 27 ewes, at nine intervals at about the time of oestrus. One group had a normal oestrus while the other two had been treated for 16 days with intravaginal sponges containing either 10 or 30 mg of a synthetic progestagen (Cronolone, Searle).

In untreated ewes, the mean level (corrected) of oestradiol-17β in plasma from the active ovary rose from 25·3 ng/100 ml at −48 h to a peak of 91·6 ng/100 ml at 0 h (onset of oestrus) and then fell. There was evidence of biphasic production. The mean level of oestrone was relatively high (13·0 ng/100 ml) at −48 h; it fell to 2·0 ng/100 ml between −36 and −24 h and then rose again to 9·4 ng/100 ml at + 12 h. There was no significant change, with time, in the plasma levels of either oestrogen from the non-active ovary. The total amounts of oestradiol-17β and of oestrone produced from both ovaries at an oestrous period were estimated to average 9·7 and 2·4 μg.

In treated ewes, a similar pattern of production of oestradiol-17β was shown by the ewes treated with 30 mg Cronolone. That of ewes treated with 10 mg differed (P < 0·01). Peak level was reached at an earlier stage, relative to the onset of oestrus, and it declined more rapidly, the total amount of oestrogen produced (oestrone + oestradiol-17β) was less (10 mg Cronolone, 8·6 μg; 30 mg Cronolone, 12·1 μg; normal oestrus, 12·1 μg), and there was no biphasic production.
EFFECT OF ADRENOCORTICOTROPHIC HORMONE AND ANDROST-5-EN-17-ON-3β-YL SULPHATE ADMINISTRATION TO THE MOTHER ON URINARY OESTROGEN EXCRETION IN LATE HUMAN PREGNANCY
Authors: JEFFERY J. , SWAPP G. H. , WILSON G. R. , FOTHERBY K.
Published: December 2008

Infusion into the mother of adrenocorticotrophin during late normal pregnancy was accompanied by rises or falls in the urinary excretion of oestrone, oestradiol and oestriol. A similar variable pattern was found when the subjects infused were receiving regular pharmacological doses of glucocorticosteroid (i.e. when maternal adrenal function was reduced) or were carrying anencephalic foetuses (i.e. when foetal adrenal function was reduced). Similar infusion of a substantial quantity of androst-5-en-17-on-3β-yl sulphate (DHAS) was accompanied by rises in oestrogen excretion by normal subjects. The rises were large compared with basal levels, but small (a few per cent) compared with the amount of DHAS infused. The changes in a pregnancy with anencephaly were within the range of the normal subjects. It is concluded that maternal DHAS plays little part in placental oestrogen synthesis, and that some control of oestrogen synthesis from DHAS occurs by the placenta itself.
THE EFFECT OF BETAMETHASONE ON GLUCOSE UTILIZATION AND OXIDATION BY SHEEP
Authors: REILLY P. E. B. , FORD E. J. H.
Published: December 2008

Continuous infusions of tracer amounts of [U-14C]glucose were used to measure the effect of a single intramuscular injection of 0·5 mg betamethasone/kg on the rates of glucose entry in six sheep eating 900 g/day chopped hay containing 49 g protein. In four of the sheep the rates of oxidation of glucose to CO2 were also measured. Hyperglycaemia occurred with a maximum plasma glucose concentration occurring 24 h after administration of the steroid. The mean glucose entry rates, expressed as mg/min/kg ± s.e.m., rose from 1·27 ± 0·11 (6) to 1·75 ± 0·16 (6). The difference between these means is significant (P < 0·001). The mean proportion of CO2 derived from glucose after administration of betamethasone (11·64 ± 1·4% (4)) was not significantly different (P > 0·5) from that derived before its administration (12·47 ± 0·34% (4)). The amounts of glucose available for synthetic purposes increased because the total production rates increased. The mean extra amount available was 11·3 ± 2·1 (4) mg C/min. These results are discussed in the light of other findings relating to the actions of the glucocorticosteroids on glucose metabolism.