bluuebunny/crossref_metadata_2025 huggingface dataset:
OESTRADIOL CONTENT OF OVARIAN VENOUS BLOOD AND OVARIAN TISSUE IN HYPOPHYSECTOMIZED RATS DURING LATE PREGNANCY
Authors: WAYNFORTH H. B. , ROBERTSON D. M.
Published: December 2008

Oestradiol-17β in ovarian venous blood and ovarian tissue was assayed by a competitive protein-binding method. Oestradiol was found in similar amounts in the ovarian vein blood of pregnant rats hypophysectomized on Day 12 and killed on Days 16 and 21 and in pregnant rats sham-hypophysectomized on Day 12 and killed on Day 16. The pituitary therefore plays no part in oestrogen production after mid-pregnancy until some time between Day 16 and Day 21, when it gives rise to an increased ovarian venous blood oestradiol content just before parturition, in intact sham-hypophysectomized rats. It is suggested that this increase is associated with the advent of the post-partum ovulation. The corpus luteum and the extraluteal component of the ovary in hypophysectomized rats autopsied on Days 16 and 21 and in sham-hypophysectomized rats autopsied on Day 16, contain similar amounts of oestradiol within each group. The extraluteal component contains about five times more oestradiol than corpora lutea in sham-hypophysectomized intact rats autopsied on Day 21. The ovaries of these animals also show an increased amount of oestradiol over that of the ovaries in the other three groups. It is suggested that secretion of oestradiol after mid-pregnancy in rats involves concurrently both the corpus luteum and the extraluteal component of the ovary.
COMPARISON OF THE EFFECTS OF VARIOUS AGENTS ON THYROIDAL ADENYL CYCLASE ACTIVITY WITH THEIR EFFECTS ON THYROID HORMONE RELEASE
Authors: KENDALL-TAYLOR PAT
Published: December 2008

Intact mouse thyroid glands were used to measure the formation of cyclic [3H]AMP from [3H]adenine, and the release of thyroidal iodine. These two parameters of thyroid activity responded to similar concentrations of human thyroid-stimulating hormone (TSH). Both were stimulated by prostaglandin E1, although the response was always very much less than to TSH. Both were inhibited by NaF, which appeared to have a toxic effect on the gland. The response to TSH was in each case reduced by lithium, suggesting that the antithyroid effect of Li+ is associated with a direct action on adenyl cyclase; however, Li+ also reduced thyroidal hormone secretion induced by dibutyryl cyclic AMP and may therefore have a second site of action.

In general, the effects of these agents on cyclic [3H]AMP formation correlated well with their effects on thyroidal iodine release. The results support the hypothesis that the activation of adenyl cyclase is closely associated with, and precedes, thyroid hormone secretion.
PRODUCTION OF PROSTAGLANDINS BY THE GUINEA-PIG UTERUS
Authors: POYSER N. L.
Published: December 2008

The production of prostaglandins by the uterus and the resting levels of prostaglandins in the uterus on selected days of the oestrous cycle were determined in guinea-pigs.

Prostaglandin F2α was detectable in the guinea-pig uterus in small amounts on days 13, 14 and 15 of the cycle. Prostaglandin E2 was present in even smaller amounts on days 14 and 15. The homogenized guinea-pig uterus had the ability to biosynthesize prostaglandins, from endogenous precursors, during incubation on every day of the cycle studied. Four to six times more prostaglandin F2α than E2 was produced on any one day with the amounts of prostaglandins formed increasing towards the end of the oestrous cycle. Indomethacin inhibited the biosynthesis of prostaglandins by the guinea-pig uterus. The implications of these findings are discussed.
VARIABILITY OF TOTAL PLASMA OESTRIOL IN LATE HUMAN PREGNANCY
Authors: MASSON G. M. , WILSON G. R.
Published: December 2008

There was no diurnal variation in plasma oestriol and diet, exercise and rest did not affect plasma oestriol levels in pregnant women. The 30-min, 3-h and day-to-day coefficients of variation compared favourably with that of 48-h urinary excretion.
HUMAN CHORIONIC SOMATO-MAMMOTROPHIN IN SERUM AND URINE IN VARIOUS STAGES OF PREGNANCY: ITS CORRELATION WITH ENZYMES AND OESTROGENS
Authors: BISWAS S. , HINDOCHA P. , DEWHURST C. J.
Published: December 2008

Human chorionic somato-mammotrophin (HCS) and the activities of heat-stable alkaline phosphatase (HSAP) and cysteine aminopeptidase (CAP) in the serum of normal pregnant women were studied. The hormone and enzymes were detectable at the early stage of pregnancy and all showed an increase with the progress of gestation. A highly significant correlation was found between HCS and activities of HSAP and CAP during all stages of gestation.

Human chorionic somato-mammotrophin and oestrogens were measured in the urine of pregnant women. The correlation coefficient between these factors was smaller than that found between serum enzymes and HCS but was still significant.
PLASMA TESTOSTERONE AND ACCESSORY SEX GLANDS IN NORMAL AND CRYPTORCHID RATS
Authors: LLOYD B. J.
Published: December 2008

Plasma testosterone concentration and the weights of the seminal vesicles and ventral prostate gland were measured in normal and cryptorchid Fischer rats at 3, 4·5, 7·5 and 13·5 months of age, and in normal parabionts and cryptorchid parabionts of 13·5 months of age. Testosterone was measured individually by a protein-binding method. In normal rats, all parameters rose to a maximum at 7·5 months of age, then levelled off or declined at 13·5 months of age. In cryptorchid rats, a similar pattern at a lower level was found for accessory sex gland weight, but plasma testosterone levels showed a progressive decline from an above normal level at 3 months to a subnormal level at 13·5 months of age. Cryptorchid parabionts were less responsive to gonadotrophin stimulation from union with a castrated partner than normal parabionts. The present study showed that plasma testosterone levels in normal and cryptorchid rats are age-related. It also showed that the pattern of plasma testosterone levels observed in cryptorchid rats is different from that seen in normal rats. Accessory sex gland weight is also age-related but is not a reliable index of plasma testosterone levels.
EFFECTS OF PREGNANCY IN THE RAT ON THE SIZE AND INSULIN SECRETORY RESPONSE OF THE ISLETS OF LANGERHANS
Authors: GREEN I. C. , TAYLOR K. W.
Published: December 2008

The secretory response of rat islets of Langerhans was examined during pregnancy and compared with insulin release in normal rat islets. The threshold for a secretory response to glucose was lowered for islets from pregnant rats by comparison with non-pregnant controls. In addition, such islets showed a greatly increased sensitivity to glucose concentrations over the range 3·5–20 mmol/1. Significantly lower fasting blood glucose levels were found in pregnant rats in vivo, compared with controls.

Insulin secretagogues other than glucose were tested for their effects on islets during pregnancy. Despite the high baseline of insulin secretion in response to glucose in pregnancy, there was an additional increased secretory response to arginine and theophylline. In contrast to their response to glucose, pregnant rat islets did not display an increased sensitivity to leucine. Glucagon, while it increased the insulin response of normal islets, had no significant effect on increasing the insulin response from pregnant rat islets suggesting that adenyl cyclase activity is already highly stimulated in pregnancy.

In addition, the insulin, DNA and protein content of islets during pregnancy were increased significantly above normal values.

The results suggested that rat islets are not only larger in pregnancy, but that they possess a more sensitive mechanism for detecting and responding to glucose and other secretagogues.
ACUTE EFFECTS OF TESTOSTERONE PROPIONATE ON FOLATE COENZYME SYNTHESIS IN THE RAT
Authors: BOVINA C. , TOLOMELLI B. , ROVINETTI C. , MARCHETTI M.
Published: December 2008

The early effects of castration and testosterone administration on folic acid metabolism in liver and accessory sex organs were studied in adult male rats. After 3 days, castration did not produce significant variations in the folate coenzyme content of the liver, whereas in the prostate and seminal vesicles it only led to a fall of formylate forms. Testosterone administration did not cause significant changes in normal rats, but in castrated ones it generally raised formylate form levels and lowered the 5-methyltetrahydrofolate content. The capacity to convert folic acid into its activated forms in vivo decreased in castrated animals; after folic acid injection, they eliminated in urine more vitamin and fewer active forms than control rats. Furthermore, the liver content of the reduced forms was less in castrated animals than in intact ones. Testosterone administration partially adjusted this biochemical alteration. Studying in vitro the enzymic activities involved in folate coenzyme metabolism, it was found that the 10-formyltetrahydrofolate synthetase alteration was the more evident and constant one in castrated rats. This enzymic activity was much decreased in the organs studied. The other enzymes showed only a very slight increase in their activity. Testosterone administration to castrated rats not only prevented the fall but stimulated 10-formyltetrahydrofolate synthetase. The present data are discussed in relation to a direct or indirect effect of testosterone on enzymes involved in folate metabolism.
ADRENOCORTICAL FUNCTION IN FOETAL, NEONATAL AND YOUNG PIGS
Authors: DVOŘÁK M.
Published: December 2008

Absolute and relative adrenal weight, blood plasma concentrations of 17-hydroxycorticosteroids and their production in vitro on incubation of adrenal slices with corticotrophin (ACTH), were measured in foetal pigs, piglets and older pigs. These criteria all indicated that adrenocortical activity was highest on the day of birth. It developed intensely in about the last 10 days of intra-uterine life. After birth it decreased progressively with age, approaching the adult level after weaning in the second month of life. The adrenal cortex of pigs of all developmental stages investigated in this study was capable of responding markedly to stimulation with ACTH. No significant differences in adrenocortical activity were found between sexes up to 90 days of age.
PERIPHERAL PLASMA PROGESTERONE DURING PREGNANCY AND THE OESTROUS CYCLE IN THE TAMMAR WALLABY, MACROPUS EUGENII
Authors: LEMON MEREDITH
Published: December 2008

Progesterone or progestin concentrations were measured in the peripheral plasma of the tammar wallaby (Macropus eugenii) during pregnancy and the oestrous cycle, using a competitive protein-binding method. In common with most other members of the marsupial family Macropodidae, the tammar has a gestation period slightly shorter than one oestrous cycle, and the occurrence of pregnancy does not affect the time of onset of the following oestrus. This study was an attempt to obtain direct evidence for the common assumption that most macropodid marsupials secrete the same amounts of ovarian hormones during pregnancy as they do during the oestrous cycle. The effect on progesterone levels of ovariectomy and removal of the corpus luteum was also studied to discover whether an extra-ovarian source of progesterone exists during pregnancy. Circulating levels of both total plasma progestins and progesterone are very low compared with other mammalian species—less than 1 ng/ml at all stages of the reproductive cycle. An increase in plasma progesterone concentration, apparently of ovarian origin, occurs before birth and/or oestrus, and this may possibly be associated with parturition. The plasma progestin concentration during pregnancy, and that of progesterone during the last 10 days of pregnancy, were significantly greater than during the oestrous cycle.
OESTRADIOL LEVELS IN THE PERIPHERAL BLOOD OF COWS DURING THE OESTROUS CYCLE
Authors: SHEMESH M. , AYALON N. , LINDNER H. R.
Published: December 2008

Changes in the peripheral plasma level of oestradiol during the bovine oestrous cycle were determined by a competitive protein-binding assay, following chromatographic purification of the steroid. Oestradiol concentration increased during the 3 days preceding oestrus and attained its peak value [17 ± 1·9 (s.e.m.) ng/100 ml] 4 h before oestrous behaviour could be detected. The level declined steeply during the day of oestrus to reach a nadir (0·8 ± 0·11) before the time of ovulation. A minor rise was observed on day 4 and a more sustained increase on days 10–13, with a peak on day 11 (8·1 ± 3·6). Comparison with published data on luteinizing hormone (LH) levels suggests that the pre-oestrous surge of oestradiol precedes the pre-ovulatory surge of LH in the cow.
THE OCCURRENCE OF TESTOSTERONE AND 5α-DIHYDROTESTOSTERONE IN THE SUBMAXILLARY SALIVARY GLAND OF THE BOAR
Authors: BOOTH W. D.
Published: December 2008

Testosterone and 5α-dihydrotestosterone were extracted from the submaxillary salivary glands of boars at different ages, but were not detected in these glands of the female pig. After purification by thin-layer and paper chromatography the steroids were identified by gas—liquid chromatography and combined gas—liquid chromatography—mass spectrometry. In the submaxillary gland of the mature boar, a high concentration of androgen (> l μg/100 g) was found, and the concentration of 5α-dihydrotestosterone was two to four times higher than testosterone. Immediate steroid precursors of testosterone which are found in boar testis were not isolated. The isolation of the two potent androgens, and the known occurrence of 16-unsaturated C19 steroids in the boar submaxillary gland, shows that there is a biochemical sexual dimorphism in this gland of the pig, which is primarily under the influence of testicular hormones.
PROTEIN SYNTHESIS IN DIFFERENT HYPOTHALAMIC AREAS DURING THE SEXUAL CYCLE IN RATS: INFLUENCE OF CASTRATION
Authors: MOGUILEVSKY J. A. , CHRISTOT JANINE
Published: December 2008

In-vitro incorporation of l-[3H]phenylalanine into proteins of the anterior, middle and posterior hypothalamus was measured in female rats given androgen soon after birth and in castrated rats. The results were compared with control animals during the sexual cycle.

Protein synthesis in the anterior hypothalamic area was higher during pro-oestrus than during oestrus and dioestrus, and lower in dioestrous than in oestrous rats. Castrated rats showed a similar rate of incorporation in this area as in the oestrous group. Protein synthetic activity in the anterior hypothalamus of androgenized rats was as low as in normal rats during dioestrus.

The highest radioactivity in the proteins of the posterior hypothalamus was found in oestrous rats. The androgenized group showed a rate of incorporation significantly higher than in dioestrus and pro-oestrus, but lower than during oestrus. Castration significantly increased the rate of incorporation of labelled amino acid into protein of the posterior hypothalamic area, as compared with the specific activity found in dioestrous and pro-oestrous groups.
EFFECT OF PORCINE, SALMON AND HUMAN CALCITONIN ON URINARY EXCRETION OF SOME ELECTROLYTES IN SHEEP
Authors: BARLET J. P.
Published: December 2008

Purified porcine and salmon calcitonin and synthetic salmon and human calcitonin were infused at the rate of 20 MRC mu./kg/h over a 96 h period in intact male lambs. Every calcitonin preparation significantly increased the urinary excretion of inorganic phosphorus, sodium, potassium and calcium, while the urinary excretion of magnesium was always significantly inhibited. Similar significant effects were observed with purified porcine calcitonin in thyroparathyroidectomized lambs supplemented with thyroxine. Oxidation of calcitonin with performic acid completely abolished its effects on plasma calcium and on the kidney. It is concluded that, when used at physiological doses, in sheep calcitonin has an important effect on urinary excretion of inorganic phosphorus, sodium and magnesium.
DIRECT MEASUREMENT OF SODIUM UPTAKE BY TOAD BLADDER MUCOSAL CELLS
Authors: FERGUSON D. R. , SMITH M. W.
Published: December 2008

A technique is described by which the unidirectional influx of sodium into toad bladder mucosal cells can be measured over short periods.

The uptake of sodium, which is linear over a 60 s contact period, changes in a non-linear way when the external sodium concentration is varied from 5 to 115mm.

Vasotocin applied to the serosal surface increases significantly the influx of sodium; amiloride applied to the mucosal surface inhibits influx. This is true whether high or low concentrations of sodium are used to bathe the mucosal surface.

The kinetics for the unidirectional influx of sodium provide direct evidence that the passage of sodium into this tissue is by some means other than simple diffusion.
DEVELOPMENT OF A RADIOIMMUNOASSAY FOR CANINE LUTEINIZING HORMONE
Authors: BOYNS A. R. , JONES GWYNETH E. , BELL E. T. , CHRISTIE D. W. , PARKES M. F.
Published: December 2008

A double antibody radioimmunoassay for canine luteinizing hormone (LH) was devised. The assay can measure immunoreactive LH in the peripheral plasma of the normal male and female dog. An increase in hormone concentration was found on the 2nd day of oestrus in the female. Ovariectomy raised plasma concentrations of the hormone to levels greater than those observed during oestrus. The administration of LH-releasing factor induced a rapid increase in the plasma concentrations of LH.
TEMPORAL EFFECTS OF PARATHYROID HORMONE ON SERUM AND URINARY CALCIUM IN THE HAMSTER
Authors: BIDDULPH D. M. , GALLIMORE L. B.
Published: December 2008

The temporal aspects of calcium addition to blood and renal conservation of calcium were compared in fasted, parathyroidectomized (PTX) hamsters after a single, intravenous injection of parathyroid hormone (PTH). Injection of 110 units of hormone rapidly stabilized urinary excretion of calcium at normal (sham-PTX) levels during a following 3-h period in contrast to the progressive and rapidly occurring hypercalciuria in animals without hormone replacement. Serum calcium concentrations increased rapidly after hormone replacement, rising 3 mg/100 ml within the first 2 h. No further increase was detected after 2 h with a significant decrease in concentration apparent between 3 and 4 h after injection of hormone. Nephrectomy, performed at intervals during the first 2-h period, resulted in significantly increased serum calcium concentrations by 4 h relative to animals with kidneys during the first 2-h period. The magnitude of this increase was directly related to the length of time kidneys were absent during the first 2 h after injection of hormone. These findings indicate that, in the hamster, the effects of PTH on the addition of calcium to blood and conservation of calcium by the kidney occur simultaneously and are both of very short duration (2 to 3 h). These short-lived effects of PTH in this species seem to be due, at least in part, to the participation of a renal influence.
INFLUENCE OF HEMITHYROIDECTOMY ON ENDOGENOUSLY LABELLED THYROXINE AND TRI-IODOTHYRONINE IN RATS
Authors: EMRICH D. , von zur MÜHLEN A. , LINDNER J. , ZIMMERMANN H. D. , BECKMANN R.
Published: December 2008

In order to investigate the influence of thyroid-stimulating hormone (TSH) on the ratio of newly synthesized thyroxine( T4):tri-iodothyronine (T3), hemithyroidectomy was performed on rats maintained on an iodinerich diet. One and two weeks after the operation the concentration of TSH increased in the plasma. As a result, the weight of the residual lobes and their thyroidal uptake of 131I/mg increased and significant histological signs of increased function in the remaining lobes were observed. The most prominent effect was a significant alteration of the ratio of newly synthesized T4:T3 in favour of T3, both in the thyroid and plasma. Four weeks after the operation, when the residual lobes weighed 57% more than those in the controls, the alterations decreased or returned to normal. The total hormone concentration in the plasma (measured as protein-bound 127I) and the oxygen consumption of the animals remained unchanged during the entire study. These findings support the hypothesis that alteration of the production and secretion ratio of T4:T3 induced by TSH might act as another regulatory factor, if a hormone deficiency originates in the peripheral cells. The results show also that changes of the T4:T3 ratio induced by TSH occur in animals on an iodine-rich diet.
PATHWAYS FOR ANDROGEN SYNTHESIS IN VITRO BY THE TESTES OF JAPANESE QUAIL (COTURNIX COTURNIX JAPONICA)
Authors: NAKAMURA TAKAO , TANABE YUICHI
Published: December 2008

The microsomal fraction of testicular tissue from Japanese quail (Coturnix coturnix japonica) was incubated with 4-14C-labelled pregnenolone, progesterone, 17α-hydroxyprogesterone, androstenedione, dehydroepiandrosterone and testosterone and [7-3H]17α-hydroxypregnenolone in a medium containing either NAD or NADPH. The metabolic products were identified by their mobilities on thin-layer chromatograms, derivative formation after oxidation and acetylation of the metabolites, and recrystallization to constant specific activity.

Three pathways for testosterone formation by the testes are suggested by the results: the first via progesterone, 17α-hydroxyprogesterone and androstenedione; the second via 17α-hydroxypregnenolone, dehydroepiandrosterone and androstenedione; and the third via 17α-hydroxypregnenolone, dehydroepiandrosterone and androst-5-ene-3β,17β-diol.
DISTRIBUTION OF SOLUBLE PROTEINS IN THE MAMMALIAN NEUROHYPOPHYSIS AND THEIR CROSS-SPECIES REACTIVITY WITH ANTI-NEUROPHYSIN
Authors: ELLIS H. K. , WATKINS W. B. , EVANS J. J.
Published: December 2008

Pituitary glands were collected from a selection of 22 domestic and exotic mammalian species. The soluble proteins extracted from the neurohypophyses were characterized by horizontal starch-gel electrophoresis at pH 8·1. Those species which were closely related phylogenetically, e.g. fallow deer and muntjac deer, pig and hippopotamus, dog and coatimundi, and members of the primates, had similar and in some cases identical protein profiles. The ability of proteins extracted from the starch-gel to cross-react immunologically with an antiserum raised against porcine neurophysin-II was determined by microimmunodiffusion. Using this technique for the identification of neurophysins in conjunction with osmotic stimulation experiments, it was found that the number of major neurophysins present in the mammalian neurohypophyses studied varied from one in the guinea-pig and hedgehog to four in man. The concept of multiple neurophysins is discussed.
THE TENTATIVE IDENTIFICATION OF THREE NEUROPHYSINS FROM THE RAT POSTERIOR PITUITARY GLAND
Authors: WATKINS W. B.
Published: December 2008

Acetone-dried rat posterior pituitary glands were extracted with 0·1mhydrochloric acid and the soluble proteins fractionated by Sephadex gel exclusion and ion exchange chromatography. Three proteins had chromatographic and biochemical properties expected of neurophysins and also cross-reacted immunologically (as demonstrated by microimmuno-diffusion and -electrophoresis in agarose) with an anti-serum raised against porcine neurophysin-II. The three proteins were named neurophysin-I, -II and -III in order of their electrophoretic mobility on starch-gel and accounted for approximately 8, 70 and 22% respectively of the total neurophysin present in the gland. The assignment of the major rat posterior pituitary lobe protein as a neurophysin (neurophysin-II) is confirmed by its ability to bind oxytocin and [8-arginine]-vasopressin. A minimum molecular weight of 10056 was calculated for neurophysin-II from its amino acid analysis and based upon the presence of one molecule of methionine and one molecule of tyrosine per molecule of protein. The stoicheiometry of the neurophysins relative to the neurohypophysial hormones is discussed.
INITIAL OBSERVATIONS ON PINEALECTOMIZED FERRETS KEPT FOR LONG PERIODS IN EITHER DAYLIGHT OR ARTIFICIAL ILLUMINATION
Authors: HERBERT J.
Published: December 2008

Removal of the pineal gland from ferrets kept entirely in daylight prevented the appearance of the normal annual oestrous rhythm. Animals were operated upon in the autumn; that is, at the start of their anoestrum. Oestrus in pinealectomized ferrets began at the usual time the following spring, as in control-operated and normal animals. However, during the second year after operation, pinealectomized ferrets came into oestrus 20–30 weeks after controls. Mean intervals between onsets of successive oestrous periods were: pinealectomized, 73·8 weeks (4 animals); control-operated, 52·9 weeks (7 animals); and normal animals, 52·5 weeks (10 animals). The duration of the oestrous period was not altered by removing the pineal.

Three other pinealectomized ferrets kept in artificial photoperiods (14 h light: 10 h darkness) showed an oestrous rhythm indistinguishable from those pinealectomized and kept in daylight, whereas four controls that had also been put into artificial light showed greatly prolonged oestrous periods lasting more than a year.

These experiments indicate that the pineal is concerned with timing the annual breeding season of ferrets in natural daylight as well as in artificial illumination. The anterior pituitary gland of pinealectomized ferrets seems unresponsive to either natural or artificial light under the conditions used in these studies. The duration of oestrus may be self-limited, but can be prolonged if the pineal gland is stimulated by the artificial 'long day'.
GONADAL HORMONES AND THE CONTROL OF OVULATION IN THE GUINEA-PIG
Authors: DONOVAN B. T. , LOCKHART A. N.
Published: December 2008

The release of ovulating hormone after acute treatment with gonadal steroids, or corpus luteum removal on different days of the oestrous cycle, was studied in the guinea-pig. Injection of 25, 50 or 100 μg oestradiol or 2·5 mg progesterone on day 13 of the cycle had no effect upon gonadotrophin secretion as judged by follicular histology, but markedly altered the sizes of the corpora lutea of the previous ovulation. Treatment with oestradiol on day 14 did not elicit gonadotrophin secretion. However, administration of the same hormones to animals given 10 μg oestradiol benzoate 24 h earlier caused ovulation or follicular luteinization. Progesterone (2·5 mg) appeared least effective in stimulating gonadotrophin release; 25 μg oestradiol were more effective when given at 12.00 h than at 24.00 h but treatment with both hormones caused ovulation when given at either time of day. Luteal volumes were not affected. Removal of corpora lutea during the second half of the cycle advanced the time of expected ovulation to day 15 or earlier when the procedure was carried out on days 8 or 9, but not on days 10–13. It is concluded that 4–5 days must elapse between the fall in plasma progesterone level associated with corpus luteum regression and the release of ovulating hormone.
LIPOLYSIS AND ADENOSINE 3′,5′-CYCLIC MONOPHOSPHATE IN ADIPOSE TISSUE OF THE NEW ZEALAND OBESE MOUSE
Authors: LOVELL-SMITH C. J. , SNEYD J. G. T.
Published: December 2008

Isolated fat cells from young New Zealand obese mice (NZO/Bl) showed an impaired rate of glycerol release in response to isoprenaline. Old animals showed an increased rate of glycerol release.

The impaired lipolysis in young animals may be caused by failure of the adenosine 3′,5′-cyclic monophosphate level to rise normally when isolated fat cells are treated with isoprenaline. It is proposed that the impaired lipolysis in young NZO/Bl mice is important in the development of obesity.
RAPIDLY-LABELLED RNA IN THE MOUSE MAMMARY GLAND BEFORE AND DURING LACTATION
Authors: BANERJEE D. N. , BANERJEE M. R.
Published: December 2008

Linear sucrose density gradient analysis showed that the synthesis of rapidly-labelled high molecular weight RNA was virtually absent in the mammary glands of virgin mice. The rapidly-labelled RNA was first evident in the mammary gland in pregnancy and was also present during lactation. The bulk of this newly-made nuclear RNA sedimented as 45S and 32S fractions after a 15-min [3H]uridine pulse period in vivo. No labelled 18S RNA was detectable in the nuclear fraction after the 15-min pulse but it was present in the cytoplasm, suggesting that the 18S RNA migrates to the cytoplasm almost immediately after its formation. Thirty minutes after injection of [3H]uridine, the initial radioactivity of the 45S region migrated to the 32S fraction and a labelled 28S peak was also present in the cytoplasmic RNA at 60 min, suggesting that the processed 28S ribosomal RNA in the mammary gland began to migrate to the cytoplasm between 30 and 60 min after the nuclear synthesis of the precursor molecule.
MEASUREMENT OF PLASMA RENIN-SUBSTRATE IN MAN
Authors: TREE MALCOLM
Published: December 2008

Values of plasma renin-substrate concentration in man vary widely according to the method of measurement used. Potential sources of variation have been tested and, as far as possible, excluded in the method described here.

Blood was diluted rapidly in an angiotensinase-inhibitor solution containing EDTA and phenanthroline; plasma was separated by centrifugation and the renin-substrate in the specimen was hydrolysed by renin to angiotensin I which was identified as such by chromatography and radioimmunoassay. Angiotensin I was used as a standard to determine the amount of angiotensin formed on incubation. Use of angiotensin II for a standard, as in other methods, led to falsely low values of plasma renin-substrate concentration. Recovery of added substrate was 94%.

Changes of plasma renin-substrate concentration in some physiological and pathological states are reported briefly.
UPTAKE AND INTERCONVERSION OF TRITIATED OESTRONE AND OESTRADIOL-17β IN THE INTACT RABBIT IN VIVO
Authors: CROCKER J. M. , THOMAS G. H.
Published: December 2008

[6,7-3H]Oestrone was infused into virgin and 24-h post-partum lactating rabbits for a period of 1 h. At the end of the infusion period the concentration of free [6,7-3H]oestrone and [6,7-3H]oestradiol-17β was determined in plasma and in selected tissues (uterus, vagina, muscle, cerebral cortex, hypothalamus and anterior pituitary). Similar studies were carried out on virgin rabbits infused with [6,7-3H]oestradiol-17β. The tissues showed characteristic differences in the concentration of labelled oestradiol-17β and in the ratio labelled oestradiol-17β:oestrone, irrespective of whether the animal was infused with tritiated oestrone or oestradiol-17β. The uterus and vagina contained predominantly oestradiol-17β, while the oestradiol-17β:oestrone ratios of the pituitary and other tissues approximated to that of the plasma.
THE BIOASSAY OF GROWTH HORMONE IN SNELL'S DWARF MICE: EFFECTS OF THYROXINE AND PROLACTIN ON THE DOSE—RESPONSE CURVE
Authors: WALLIS M. , DEW JENNIFER A.
Published: December 2008

Pituitary growth hormone has a dose-dependent growth promoting effect in pituitary dwarf mice (Snell's strain), and this effect can be used as the basis of a bioassay for the hormone. Prolactin and thyroxine also promote growth in these animals, and the effects of these hormones in combination with growth hormone were studied, in order to see whether their presence might enhance the precision or sensitivity of the growth hormone assay.

When prolactin and/or thyroxine were administered with growth hormone, the growth response observed was no greater than the sum of the effects of the hormones given separately; in some cases it was less. Neither prolactin nor thyroxine increase the sensitivity or precision of the growth hormone bioassay. The implications of these results for theories about the mechanisms of growth promotion by these hormones are considered.
ASSAY OF CORTISOL, CORTICOSTERONE, 11-DEOXYCORTISOL AND CORTISONE IN OVINE PERIPHERAL AND ADRENAL VENOUS PLASMA
Authors: CLEMENTS A. S. , NEWSOME H. H.
Published: December 2008

An assay was devised, using Sephadex LH-20 chromatography and competitive protein binding, to measure cortisol, corticosterone, 11-deoxycortisol and cortisone in a single extract of 4 ml peripheral plasma or 50–300 μl adrenal venous plasma in sheep. The method is especially suited for measuring the low concentrations of these steroids in ovine plasma. Mean values (μg/100 ml) in dexamethasone-suppressed plasma were cortisol, 0·042; corticosterone, 0·004; 11-deoxycortisol, 0·004; and cortisone, 0·021. Mean values (μg/100 ml) in basal plasma were cortisol, 1·11; corticosterone, 0·044; 11-deoxycortisol, 0·020; and cortisone, 0·24. Peripheral concentrations of all four steroids increased in response to corticotrophin, but none increased after angiotensin. Metyrapone administration produced a marked rise in deoxycortisol. The method provided direct evidence that cortisone and deoxycortisol were secreted by the adrenal gland in sheep.
PURIFICATION AND PROPERTIES OF CHORIONIC GONADOTROPHIN FROM TROPHOBLASTIC TISSUE, URINE AND PLASMA OF A PATIENT WITH A HYDATIDIFORM MOLE
Authors: PALA A. , MEIRINHO M. , BENAGIANO G.
Published: December 2008

Purified human chorionic gonadotrophin (HCG) fractions were obtained from urine, peripheral plasma and chorionic tissue of a woman with hydatidiform mole by a combination of DEAE-cellulose and DEAE-Sephadex ion exchange chromatography and gel filtration on Sephadex G-100. Homogeneity of the purified fractions obtained was demonstrated by analytical polyacrylamide gel electrophoresis and immunoelectrophoresis. The preparation from plasma had a higher ratio of biological to immunological activity than the urine or tissue preparation. The biological potency of the plasma HCG was 23000 i.u./mg, whereas the urinary and the trophoblastic tissue preparations showed a potency of 20000 and 6500 i.u./mg, respectively.

Further characterization of the three fractions was achieved by analytical isoelectric focusing and determination of the molecular weight. The peak of radioimmunological activity after isoelectric focusing was found to be, in all three cases, at pH 4·90 and the molecular weight obtained after incubation with sodium dodecyl sulphate and urea was around 63000 When the molecular weight was determined after incubation in a medium containing 4 m-urea, sodium dodecyl sulphate and 2-mercaptoethanol two separate fractions were obtained from each of the three preparations. The heavier fraction showed a molecular weight of approximately 35000 and the lighter fraction had a molecular weight of approximately 27000.
SEASONAL VARIATION IN THYROID HORMONOGENESIS IN THE INDIAN GARDEN LIZARD, CALOTES VERSICOLOR
Authors: THAPLIYAL J. P. , CHANDOLA ASHA
Published: December 2008

The metabolism of radioactive iodine in the adult male garden lizard, Calotes versicolor, was studied during the course of a year by examination of the following indices of thyroid function: thyroidal 131I uptake, quantitative estimation of labelled iodoamino acids in the thyroid gland and in plasma, and plasma protein-bound iodine. Labelled monoiodotyrosine, di-iodotyrosine and thyroxine were identified and seasonal variations in their proportions demonstrated. Thyroxine was not detected in winter but made its appearance in the spring and summer months. Tri-iodothyronine was not detected at any time of the year in the thyroid of Calotes.

The effects of administration of thyrotrophin (TSH), lowered temperature and dehydration were also studied. TSH augmented 131I incorporation into the thyroid gland significantly but was not effective in stimulating hormonogenesis in winter. While water withdrawal had no effect on thyroidal radioactive iodine uptake, temperature lowered artificially (15 °C) in summer reduced it by half, and altered greatly the proportions of iodoamino acids in the thyroid. The results are discussed in the light of the fragmentary information concerning thyroid function in reptiles.
THE IMMUNOCHEMICAL SPECIFICITY OF ANTISERA TO BOVINE PARATHYROID HORMONE: AN APPROACH TO REGION-SPECIFIC RADIOIMMUNOASSAY
Authors: MURRAY T. M. , KEUTMANN H. T.
Published: December 2008

Six different antisera to bovine parathyroid hormone were characterized immunochemically by comparing their reactivity towards amino-terminal (1–29) and carboxyl-terminal (53–84) fragments of the hormone molecule. Three of the antisera were primarily amino-terminally directed. One antiserum contained antibody populations to at least three discrete sites; two other antisera each contained two antibodies directed against each end region of the hormone. By saturating one of these antisera with one or the other of the end fragments of the hormone, specific immunoassays for the amino-terminal and carboxyl-terminal regions of the molecule were developed. Such techniques may be applied to improving the specificity of the radioimmunoassay for parathyroid hormone by eliminating interference from carboxyl-terminal hormonal fragments which circulate in human plasma.
THE STEROIDOGENIC RESPONSE OF ADULT RAT ADRENOCORTICAL CELLS IN MONOLAYER CULTURE
Authors: O'HARE M. J. , NEVILLE A. MUNRO
Published: December 2008

Quantitative aspects of corticosteroidogenesis were examined in monolayer cultures of cells from the zona fasciculata and zona reticularis of the adult rat adrenal cortex, maintained for up to 4 months. Corticosterone secretion continued at a steady rate in cultures maintained with corticotrophin (ACTH), the output of maximally stimulated cultures being approximately 12 μg/106 adrenocortical cells/day. In the absence of ACTH, a small amount of 20α-hydroxypregn-4-en-3-one, but no detectable corticosterone, was secreted, resulting in a fluorogenic steroid output 1/125 th of that of maximally stimulated cultures. Restimulation with ACTH of cultures maintained for up to 2 months in its absence resulted in maximum levels of corticosterone secretion after 4–5 days of continuous ACTH treatment. The levels of corticosterone secretion attained on restimulation were similar to those observed in cultures maintained with ACTH from the out set. Withdrawal of ACTH resulted in a fall in steroid output which took 10 days to reach final unstimulated levels. Trophic stimulation of corticosteroidogenesis with a similar time-course was obtained with both cyclic AMP and dibutyryl cyclic AMP, the latter being the more effective.
LUTEINIZING HORMONE AND PROGESTERONE IN PERIPHERAL BLOOD DURING THE OVULATORY CYCLE OF THE HEN GALLUS DOMESTICUS
Authors: FURR B. J. A. , BONNEY ROSEMARY C. , ENGLAND ROWENA J. , CUNNINGHAM F. J.
Published: December 2008

Radioimmunoassays were used to estimate luteinizing hormone (LH) and progesterone in samples of blood taken from individual hens at frequent intervals throughout their respective ovulatory cycles. A consistent pattern in the plasma levels of both hormones was observed. Significantly more LH and progesterone was present in plasma 4–7 h before ovulation than at other times during the cycle. An increase in the level of progesterone either preceded that of LH or the two hormones increased simultaneously. At no time did an increase in the level of LH occur before the rise in progesterone. In those birds which did not ovulate during the experimental period the levels of both hormones remained low. The significance of these findings in relation to the neuroendocrine control of ovulation in the hen is discussed.
THE EFFECT OF PROGESTERONE AND OESTRADIOL ON IMMATURE MOUSE UTERI MAINTAINED AS ORGAN CULTURES
Authors: GRANT P. S.
Published: December 2008

Uterine horns from immature mice were cultured for 2 days in Trowell's T8 medium containing 20% foetal calf serum and either ethanol (0·125%), oestradiol-17β (5 μg/ml), progesterone (5 μg/ml) or progesterone plus oestradiol (5 μg + 5 μg/ml). The uteri were fixed in Bouin's fluid and the degree of closure of the lumen was assessed by an independent observer after examination of histological sections.

Uteri treated with oestradiol alone usually did not differ from those treated with ethanol: progesterone treatment either alone or in combination with oestradiol led to luminal closure.
THE EFFECT OF CERTAIN STILBOESTROL ANALOGUES ON PLASMA PROLACTIN AND TESTOSTERONE IN THE RAT
Authors: DANUTRA VARAPAN , HARPER M. E. , BOYNS A. R. , COLE E. N. , BROWNSEY B. G. , GRIFFITHS K.
Published: December 2008

Oestradiol-17β, diethylstilboestrol (DES), dl-dihydrodibutylstilboestrol (dl-DHBS) and meso-dihydrodibutylstilboestrol (meso-DHBS) were injected intramuscularly into male Sprague-Dawley rats in a daily dose of 100 μg for a period of 10 days. Oestradiol-17β and DES decreased the weight of the prostate and seminal vesicles to the same extent, whereas meso-DHBS was less effective. dl-DHBS was almost inactive. Only oestradiol-17β and DES caused a decrease in the weight of the testes. The adrenal glands increased in weight after administration of either oestradiol-17β, DES or meso-DHBS.

Four hormones in the plasma were measured: testosterone, androstenedi-one, prolactin and interstitial cell-stimulating hormone (ICSH). DES decreased the plasma concentration of both ICSH and testosterone. Oestradiol-17β and meso-DHBS administration resulted in a lowering of the plasma testosterone concentration with no effect on ICSH. Oestradiol-17β, DES and meso-DHBS markedly increased plasma prolactin concentrations. dl-DHBS appeared to have little biological effect causing only very small changes in all the parameters investigated.
CONCENTRATION OF PROGESTERONE IN SYSTEMIC PLASMA OF GOATS: EFFECTS OF VARIOUS ROUTES OF ADMINISTRATION
Authors: DHINDSA D. S. , RESKO J. A. , METCALFE J.
Published: December 2008

The effect of various routes of administration on the plasma concentrations of progesterone was studied in Pygmy goats. Oral administration, even in extremely high doses, gave low plasma concentrations which returned to normal within 24 h. Progesterone given by subcutaneous or intra-abdominal implantation in silicone rubber (Silastic) envelopes caused a marked rise in the plasma concentration of progesterone, values reaching 10–30 ng/ml at 10–20 days but then declining. A fall in plasma concentration despite continued administration was also observed with daily intramuscular injections of large doses of progesterone. This observation suggests that some physiological mechanism prevents sustained high plasma levels of this hormone.
THE LACTOGENIC EFFECTS OF PROLACTIN AND GROWTH HORMONE ON MAMMARY GLAND EXPLANTS FROM VIRGIN AND PREGNANT SPRAGUE-DAWLEY RATS
Authors: HALLOWES R. C. , WANG D. Y. , LEWIS D. J.
Published: December 2008

Explants of mammary glands from mature virgin and pregnant Sprague—Dawley rats were maintained in organ culture for up to 96 h. The effects of insulin, corticosterone, ovine prolactin and bovine growth hormone on the synthesis of DNA, RNA and casein in the explants were studied.

DNA synthesis in explants from virgin rats was maintained by insulin but was not increased by the addition of the other hormones tested. DNA synthesis in explants from pregnant rats was increased by insulin, and the addition of corticosterone and either prolactin or growth hormone to the culture medium increased this synthesis. The rate of RNA synthesis in explants from virgin rats was similar in medium 199 with or without additional hormones. RNA synthesis in explants from pregnant rats was increased by the addition of insulin or insulin plus corticosterone to the medium. In explants from both virgin and pregnant rats the maximal rate of hormone-stimulated DNA or RNA synthesis occurred during the first 24 h of culture.

Casein synthesis, as measured by the uptake of 32P-labelled orthophosphate by explants from virgin and pregnant rats, was increased by insulin plus corticosterone plus either prolactin or growth hormone. The rate of casein synthesis was maximal between 48 and 72 h and was reduced by actinomycin D. In the pregnant rats no significant differences were demonstrated between the effects of the hormones on DNA, RNA or casein synthesis in explants from the 5th, 10th, 16th or 19th day of pregnancy.
BINDING OF 5α-ANDROSTANE-3α,17β-DIOL TO HUMAN PLASMA PROTEINS
Authors: CLARK A. F. , BIRD C. E.
Published: December 2008

The binding of 5α-androstane-3α,17β-diol to human plasma proteins was studied by equilibrium dialysis. The mean value of 96·6% for men was significantly less than that of 97·5% for women. These values are higher than those found for 5α-dihydrotestosterone (95·0 and 97·3%, respectively) and for testosterone (92·4 and 95·3%, respectively). When the distribution of labelled steroid in the different protein fractions was studied by paper electrophoresis, male plasma showed a larger fraction of 5α-androstane-3α,17β-diol radioactivity in the albumin fraction and less in the β-globulin area than did female plasma. Similar finding were made when 5α-dihydrotestosterone was studied. No inter-α-globulin peak of radioactivity was found for 5α-androstane-3α,17β-diol and 5α-dihydrotestosterone as occurs for testosterone. Albumin binds more 5α-androstane-3α,17β-diol than 5α-dihydrotestosterone or testosterone when studied by equilibrium dialysis and this is due to a higher apparent association constant between albumin and the dihydroxysteroid.
PROGESTERONE SECRETION BY THE SHEEP CORPUS LUTEUM AFTER REPEATED INFUSIONS OF LUTEINIZING HORMONE AND HUMAN CHORIONIC GONADOTROPHIN
Authors: BAIRD D. T. , COLLETT R. A.
Published: December 2008

The response of the ovine corpus luteum to repeated infusions of luteinizing hormone (LH) or of human chorionic gonadotrophin (HCG) was tested in four ewes with the left ovary autotransplanted to the neck. Constant infusion for 1 h of either LH (100 or 1000 μg/h) or HCG (200 i.u./h) via the ovarian artery stimulated a temporary increase in secretion of progesterone which fell to control levels by 60 min. Ovarian blood flow increased progressively (P < 0·05) throughout the infusion of gonadotrophin in three of the five experiments. A second infusion of either gonadotrophin after a further control hour failed to stimulate progesterone secretion. These results suggest that ovine luteal tissue rapidly becomes refractory to the steroidogenic effect of LH in vivo.
OBSERVATIONS ON THE RELEASE AND CLEARANCE OF NEUROPHYSIN AND THE NEUROHYPOPHYSIAL HORMONES IN THE RAT
Authors: FORSLING MARY L. , MARTIN MARION J. , STURDY J. C. , BURTON ANGELA M.
Published: December 2008

Circulating levels of neurophysin, oxytocin and vasopressin were determined in rats under various physiological conditions using bovine neurophysin as the reference standard. Under resting conditions the mean plasma concentration of immunoreactive neurophysin was 6·2 ± 2·4 ng/ml while oxytocin and vasopressin were undetectable.

Neurophysin and vasopressin were released in response to haemorrhage in Wistar and heterozygous Brattleboro rats; in the homozygous strain haemorrhage resulted in a release of oxytocin and neurophysin. Infusion of 0·1 M-calcium chloride into Wistar rats caused a rise in plasma neurophysin, oxytocin and vasopressin. The half-times for the disappearance from the plasma of arginine-vasopressin and neurophysin in the circulation were 1·6 ± 0·8 (S.D.) and 3·4 ± 0·9 min respectively.