bluuebunny/crossref_metadata_2025 huggingface dataset:
PARATHYROID HORMONE IN FOETAL AND ADULT SHEEP: THE EFFECT OF HYPOCALCAEMIA
Authors: SMITH F. G. , ALEXANDER D. PAULINE , BUCKLE R. M. , BRITTON H. G. , NIXON D. A.
Published: December 2008

Measurable levels of immunoassayable parathyroid hormone (PTH) were present in the plasma of two out of five sheep foetuses of 80–142 days gestational age, and in three of the mothers at Caesarian section. There was no correlation between foetal and maternal concentrations although the range of values was similar.

In response to foetal hypocalcaemia induced by EDTA infusion the plasma PTH concentration rose in all of the foetuses and there was a highly significant inverse correlation between the foetal plasma calcium and PTH levels. During the period of foetal hypocalcaemia the maternal plasma PTH levels did not change significantly. EDTA was also infused into three adult ewes. There was a similar rise in the concentration of PTH in the plasma of these ewes and it was concluded that the level of responsiveness of the foetal parathyroid gland to plasma calcium concentration was similar to that of the adult.

The parathyroid glands would appear to be active from an early stage in foetal life and responsive to changes in serum calcium level.
THE DISTRIBUTION OF [3H]PROGESTERONE AND [3H]MEGESTROL ACETATE IN THE UTERUS OF THE OVARIECTOMIZED RAT
Authors: JOHN P. N. , ROGERS A. W.
Published: December 2008

The distribution of radioactivity was studied autoradiographically in the uterus of the ovariectomized rat from 1 to 7 h after the s.c. injection of [3H]progesterone. Luminal and glandular epithelia were less radioactive than stroma or muscle. Grain densities over nuclei were the same as those over cytoplasm in the epithelial tissues and the muscle. Pretreatment with non-radioactive progesterone did not alter the pattern of distribution of radioactivity though in one experiment grain densities were significantly decreased in the pretreated animal; this decrease involved nucleus and cytoplasm in epithelial cells and in the muscle.

The interpretation of grain densities after the administration of [3H]progesterone is complicated by the presence of labelled metabolites. Further experiments were therefore carried out with [3H]megestrol acetate, a progestin which is not significantly metabolized in the uterus or plasma during the first 3 h after injection s.c. At 30 min, 1 and 2 h after [3H]megestrol acetate administration, the stroma and muscle were twice as radioactive as the epithelial tissues of the uterus. Nuclear and cytoplasmic grain densities were the same, both in the luminal epithelium and the stroma. Pretreatment with non-radioactive progesterone decreased the observed grain densities by 20–30% in all tissues including the extracellular spaces of the stroma. Though stromal cells were more radioactive than the surrounding extracellular spaces 1 h after [3H]megestrol acetate, the luminal epithelium was significantly less radioactive.

These results are consistent with the hypothesis that binding sites for progesterone are at relatively low concentrations in the uterus of the ovariectomized rat, that they are widely distributed in the uterus, and that after binding to these sites progestins are distributed between nucleus and cytoplasm in approximately equal proportions.
OESTROGEN SYNTHESIS IN RAT OVARIES IN VITRO: EFFECTS OF ENDOGENOUS AND EXOGENOUS GONADOTROPHINS
Authors: ROBINSON BRENDA , OAKEY R. E.
Published: December 2008

The rate of synthesis of [14C]oestrone and [14C]oestradiol-17β from [14C]testosterone in vitro by ovaries from rats at different stages of the oestrous cycle was measured. The rate of [14C]oestrogen synthesis was highest in ovaries taken from rats in pro-oestrus and lowest in ovaries taken from rats early in the dioestrous phase of the cycle. Rates of synthesis in ovaries obtained from rats in the late dioestrous stage were intermediate between the rates of the other groups. The rates of [14C]oestrogen synthesis at these periods of the cycle paralleled the concentrations of oestrogens in ovarian vein plasma reported by other authors.

Gonadotrophin preparations with either luteinizing hormone activity or both follicle-stimulating hormone and luteinizing hormone activities had no effect on [14C]oestrogen synthesis by rat ovaries in vitro at any of these stages of the oestrous cycle.
FEEDING AND CALCITONIN SECRETION IN SHEEP
Authors: PHILLIPPO M. , LAWRENCE C. B. , BRUCE J. B. , DONALDSON D. R.
Published: December 2008

Calcitonin (CT) secretion was measured before, during and after feeding in three sheep with an exteriorized lobe of the thyroid gland. A significant (P < 0·05) increase in the rate of CT secretion occurred during the 15-min period immediately after the presentation of the food: this increase could be blocked by the local infusion of 35 nm-( ± )-propranolol. During the subsequent 165 min, the secretion of CT was not significantly altered from that before feeding. These results suggest that in the sheep there is an initial increase in CT secretion mediated via a β-adrenergic system and it is possibly associated with the excitement of receiving the food. In the remainder of the first 180 min after presentation of a feed, the rate of release was unaffected.
URINARY EXCRETION OF SODIUM AND POTASSIUM IN RELATION TO PLASMA ALDOSTERONE CONCENTRATION
Authors: ADAMSON A. R. , JAMIESON S. W.
Published: December 2008

The effect of a low dose infusion of aldosterone (7·0–8·4 ng/kg/min) on urinary sodium and potassium excretion was assessed in six normal subjects. Plasma aldosterone levels during these infusions (mean 38, range 23–62 ng/100 ml) compared favourably with levels obtained during Na+ deprivation (mean 38, range 30–46 ng/100 ml). In four paired experiments, aldosterone infused in this dose for 2 h produced a significant reduction in Na+ excretion (P < 0·01) and urine volume (P < 0·05) in the 4th hour after the start of the infusion compared with the control infusions. There was no significant change in K+ excretion. Prolonging the aldosterone infusion reduced Na+ excretion. A 10 h infusion of aldosterone (7·7 ng/kg/min) in one subject reduced Na+excretion to 6 μequiv./min. These results are compared to the levels of Na+ excretion obtained in dietary Na+ deprivation.
PLASMA PROLACTIN MEASURED BY RADIOIMMUNOASSAY AND BIOASSAY IN PREGNANT AND LACTATING GOATS AND THE OCCURRENCE OF A PLACENTAL LACTOGEN
Authors: BUTTLE H. L. , FORSYTH ISABEL A. , KNAGGS G. S.
Published: December 2008

Plasma samples from five goats taken during their first pregnancies and subsequent lactation were examined for prolactin concentration by a radioimmunoassay and for total lactogenic activity by a rabbit mammary gland organ culture assay.

Prolactin was released in response to suckling and there was a fair correlation between prolactin concentrations as measured by radioimmunoassay and the levels of total lactogenic activity in the plasma samples from the lactating animals. During pregnancy, however, high levels of lactogenic activity were detected in the second and last thirds of pregnancy when the concentration of immunoreactive prolactin was low or even absent. This discrepancy in the results of the two assays suggests that the blood of pregnant goats contains a second lactogen of placental origin which does not cross-react with prolactin.
THE PENETRATION OF IODINE-LABELLED FOLLICLE-STIMULATING HORMONE AND ALBUMIN INTO THE SEMINIFEROUS TUBULES OF SHEEP AND RATS
Authors: SETCHELL B. P. , WALLACE A. L. C.
Published: December 2008

The entry of 125I-labelled ovine follicle-stimulating hormone (FSH) and human serum albumin into the seminiferous tubules of rams has been studied by measuring radioactivity in blood plasma and rete testis fluid after an intravenous injection of the labelled protein. After the injection of FSH, radioactivity/mg total protein in rete testis fluid exceeded that in blood plasma from the first day onwards, but after the injection of human serum albumin, radioactivity/mg total protein in rete testis fluid only reached that in plasma after 4–5 days and never exceeded it. Protein-bound radioactivity disappeared from the blood more quickly after an injection of FSH than after an injection of albumin.

The volume of distribution for ovine FSH in the testes of rats was greater than that for human serum albumin. The volume of distribution for FSH was greater, in absolute terms, in the testes with the efferent ducts ligated 24 h previously than in the contralateral control testes when the FSH was injected at the time of efferent duct ligation. The volume of distribution for albumin was slightly less in the ligated testes than in the control testes. This suggests that FSH but not albumin had penetrated into the fluid trapped inside the testis. The liver and kidney had much higher concentrations of protein-bound radioactivity per unit weight than did the testis after the injection of FSH, so it does not seem that FSH is selectively taken up by the testis.
EFFECTS OF CARP PITUITARY FRACTIONS ON VITELLOGENESIS, OVARIAN MAINTENANCE, AND OVULATION IN HYPOPHYSECTOMIZED CATFISH, HETEROPNEUSTES FOSSILIS (BLOCH)
Authors: SUNDARARAJ B. I. , ANAND T. C. , SINHA V. R. P.
Published: December 2008

Carp pituitary extracts obtained from the puntius carp, Puntius gonio-notus, the grass carp, Ctenopharyngodon idellus, and the big head carp, Aristichthys nobilis, were subjected to gel filtration on Sephadex G-100. The water-soluble proteins in the pituitary extracts resolved into three distinct components, referred to as fractions I, II and III. They were tested for their gonadotrophic activity in the female catfish, Heteropneustes fossilis, by evaluating ovarian maintenance and ovulation in hypophysectomized gravid specimens during the spawning season (July—August), and the induction of oogenesis and vitellogenesis in the regressed ovaries of hypophysectomized specimens during the preparatory period (February). Daily treatment with the puntius carp pituitary fraction II (100 or 300 μg) reinitiated and restored oogenesis and vitellogenesis. The grass carp pituitary fraction II (300 μg) induced vitellogenesis but its potency was much less than that of the puntius carp pituitary fraction II. The big head carp pituitary fraction II was ineffective. Daily treatment with the puntius carp pituitary fraction II (1 or 5 μg) maintained the yolky oocytes in the gravid ovaries and prevented atresia. Ovulation and spawning were induced in hypophysectomized gravid catfish by a single dose of the puntius carp pituitary fraction II (100 or 150 μg). The first and third fractions from the three species of carps were ineffective. Thus, all the reproductive processes in the hypophysectomized female catfish were initiated and/or maintained solely by the puntius carp pituitary fraction II.
PLASMA LEVELS OF LUTEINIZING HORMONE IN WOMEN AND IN RATS AS MEASURED BY BIOASSAY
Authors: WATSON J.
Published: December 2008

Plasma levels of luteinizing hormone (LH) in normally cyclic women during the menstrual cycle and in rats during the oestrous cycle were measured by bioassay. With the human subjects, it was possible to establish a mid-cycle peak of LH and correlate it with basal body temperature, while with the rats a peak of LH secretion was noted between 15.00 and 19.00 h on the day of pro-oestrus. The levels of LH in both groups of subjects were of the same order as those measured by other assay techniques.
THE EFFECTS OF CITRIC ACID CYCLE INTERMEDIATES, α-GLYCEROPHOSPHATE AND LACTIC ACID ON STEROID SYNTHESIS IN RABBIT OVARIAN HOMOGENATES
Authors: SCOON V. , MAJOR PATRICIA W.
Published: December 2008

Rabbit ovarian homogenates were incubated in Krebs—Ringer bicarbonate buffer with or without glucose in the presence of citric acid cycle intermediates, α-glycerophosphate and lactic acid. The effects of these compounds on steroid synthesis were then observed. The inclusion of glucose alone in the medium was sufficient to increase progesterone biosynthesis. Succinate stimulated total progestational steroid synthesis both in the presence and absence of glucose in the medium, while citrate had an inhibitory effect in both cases. Malate stimulated synthesis only in the absence of glucose, while oxaloacetate and α-glycerophosphate stimulated synthesis only when glucose was present in the medium. Lactic acid had no effect in the absence of glucose, but significantly inhibited synthesis when glucose was present in the medium.
EFFECT OF ELECTRICAL STIMULATION OF THE HYPOTHALAMUS ON GONADOTROPHIN RELEASE AND THE ONSET OF PUBERTY
Authors: MEIJS-ROELOFS H. M. A.
Published: December 2008

Electrical stimulation of the hypothalamus with biphasic pulses was performed in immature female rats. When performed at 27 days of age or later, electrical stimulation in the arcuate nucleus region advanced puberty in all animals, as did stimulation of the anterior hypothalamus at 29 days of age or later. Stimulation in younger rats did not uniformly advance puberty. The responsiveness to electrical stimulation thus seems to develop a few days earlier in the arcuate nucleus region than in the anterior hypothalamus.

In a second experiment the possible involvement of follicle-stimulating hormone (FSH) in the advancement of puberty was investigated: the simplified augmented ovarian weight assay for endogenous FSH was performed in rats stimulated in the arcuate nucleus region as well as in controls. A marked increase in ovarian weight, indicating increased FSH levels, was demonstrated in all animals stimulated on day 27 or later; at earlier ages only a percentage of the stimulated animals responded. This percentage paralleled the percentage of animals that showed advancement of puberty.

It is concluded that electrical stimulation in both the arcuate nucleus region and the anterior hypothalamus advances the onset of puberty. It is suggested that electrical stimulation causes increased plasma FSH levels and, in consequence, precocious puberty.
ACTIVATION OF SOLUBILIZED STEROID-TRANSFORMING ENZYMES OF ADRENAL MICROSOMAL ORIGIN BY SERUM PROTEINS
Authors: HAMILTON MARGOT A. , McCUNE R. W. , ROBERTS SIDNEY
Published: December 2008

The reactions which result in the conversion of pregnenolone to progesterone and of progesterone to deoxycorticosterone in undisrupted microsomal preparations from rat adrenal glands were stimulated by homologous serum. The active materials were shown to be firmly associated with serum proteins. The dialysable fraction of serum was either without effect on these transformations or was inhibitory. The enzyme systems involved were partially solubilized by exposure of the microsomal preparation to prolonged sonic treatment or to 1% Triton N-101. After either treatment, 35–40% of the original specific activity of the steroid 21-hydroxylase system responsible for the conversion of progesterone to deoxycorticosterone was found in the supernatant fraction after high-speed centrifugation. However, this solubilized system did not respond to serum preparations. The same procedures also resulted in a supernatant fluid which showed about 50–60% of the initial specific activity of the multi-enzyme system involved in the conversion of pregnenolone to progesterone. In these instances, the stimulatory effect of serum was retained or accentuated. Acetone powders prepared from the adrenal microsomal fraction were also active in the conversion of pregnenolone to progesterone and responded to serum with enhanced activity. Earlier observations that activation of steroid 21-hydroxylase by homologous rat serum was specific for the β-globulin fraction were confirmed in the present investigations. In contrast, stimulation of the conversion of pregnenolone to progesterone was apparently due principally to the albumin fraction. Albumin preparations from a number of other sources, as well as whole human serum protein, were also effective in this regard. The active protein preparations selectively stimulated 4-ene-3β-hydroxysteroid dehydrogenase activity, but did not activate 5-ene-3-oxosteroid isomerase in the microsomal fraction. This finding suggested that activation of 5-ene-3β-hydroxysteroid dehydrogenase was responsible for stimulation of progesterone synthesis from pregnenolone. The results indicate that the protein-bound factor in rat serum which was capable of stimulating the conversion of progesterone to deoxycorticosterone in microsomal preparations from rat adrenal glands was different from that which activates the conversion of pregnenolone to progesterone. Moreover, these diverse factors appeared to act by different mechanisms.
GROWTH AND REGRESSION OF THE CORPORA LUTEA FORMED IN GUINEA-PIGS IN RESPONSE TO TREATMENT WITH EXOGENOUS GONADOTROPHIN
Authors: DONOVAN B. T. , LOCKHART A. N.
Published: December 2008

The growth and functional activity of luteal bodies formed in the ovaries of guinea-pigs given exogenous gonadotrophin was examined. Folliclestimulating hormone, luteinizing hormone, both hormones together, and both hormones supplemented with prolactin, were given on day 13. Vaginal oestrus occurred 8–12 days later, irrespective of the kind of hormone given. The sizes of luteal bodies induced in intact and hysterectomized guinea-pigs were compared with those of similarly aged naturally formed corpora lutea 8 and 11 days after ovulation. The artificially induced bodies were smaller than normal corpora lutea, but grew to match their size after hysterectomy.
EFFECT OF l-DOPA ADMINISTRATION ON GROWTH HORMONE SECRETION IN NORMAL SUBJECTS AND PARKINSONIAN PATIENTS
Authors: CAVAGNINI F. , PERACCHI M. , SCOTTI G. , RAGGI U. , PONTIROLI A. E. , BANA R.
Published: December 2008

The effect of both oral and intravenous administration of l-DOPA on growth hormone (GH) secretion was studied in a group of normal volunteers: a significant rise of serum GH levels was observed in both cases.

Growth hormone release in response to insulin hypoglycaemia and to arginine infusion was evaluated in a group of Parkinsonian patients before and after 25 days' treatment with l-DOPA plus a DOPA-decarboxylase inhibitor. In addition, GH response to the above stimuli was studied in a group of patients who had been under treatment for more than 6 months with l-DOPA alone. In untreated Parkinsonian patients, GH response to insulin hypoglycaemia was at the lower limit of normal range while arginine-induced GH release was significantly reduced. Treatment with l-DOPA did not increase GH responses. Some possible interpretations of the results are discussed.

The findings support the possibility that dopamine plays a role in the physiological regulation of GH secretion, as in the case of luteinizing hormone, follicle-stimulating hormone and prolactin release.
EFFECTS OF ADMINISTERING ANTISERA TO MOUSE GROWTH HORMONE AND PROLACTIN ON GAIN IN LITTER WEIGHT AND ON MAMMARY NUCLEIC ACID CONTENT OF LACTATING C3H MICE
Authors: SINHA Y. N. , LEWIS U. J. , VANDERLAAN W. P.
Published: December 2008

The effects of administering antiserum to mouse growth hormone (GH) and prolactin on lactation and mammary nucleic acid content of C3H mice were studied. Injections of either antisera to lactating mothers suppressed the gain in body weight of their suckling young, GH antiserum more readily than prolactin antiserum. A combined injection of the two antisera resulted in an immediate retardation of the gain in body weight of the young. Although both antisera reduced DNA and RNA content of the mammary gland, GH antiserum appeared to affect DNA content predominantly whereas prolactin antiserum affected RNA: DNA ratio, suggesting involvement of GH primarily in cell proliferation and of prolactin in protein synthesis. Both antisera abolished the gain in maternal body weight. Mouse GH antiserum decreased maternal adrenal weight whereas both antisera reduced ovarian weight. The results suggest that both GH and prolactin may be involved in normal lactation and in maintenance of body weight in C3H mice.
OESTRONE AND OESTRADIOL IN JUGULAR VEIN PLASMA DURING THE OESTROUS CYCLE OF THE COW
Authors: MASON B. D. , KRISHNAMURTI C. R. , KITTS W. D.
Published: December 2008

The concentrations of oestrone and oestradiol in jugular vein plasma during the bovine oestrous cycle were measured using a fluorescence assay. The highest levels of both oestrogens were found on the 19th and 20th days of a standardized 21-day cycle, with the peak of oestrone occurring slightly before that of oestradiol. Oestrone values ranged from 23·1 to 226·9 ng/100ml and oestradiol varied between 17·6 and 117·5 ng/100 ml. Relatively high values for oestrone concentrations were found on days 6, 7 and 8. These values are comparable to those observed in the ovarian vein blood of the ewe, using both the present method and radioimmunoassay.

The relationship between the oestrogen concentrations reported here and the levels of other hormones during the bovine oestrous cycle is discussed.
ULTRASTRUCTURE OF THE UTERINE EPITHELIUM DURING THE HORMONAL INDUCTION OF SENSITIVITY AND INSENSITIVITY TO A DECIDUAL STIMULUS IN THE MOUSE
Authors: POLLARD ROSEMARY M. , FINN C. A.
Published: December 2008

Uterine sensitivity and insensitivity to a decidual stimulus were induced in ovariectomized mice by daily treatment with progesterone and oestradiol. Uteri from these animals were examined with the electron microscope in an attempt to correlate ultrastructural changes with these states.

Progesterone alone brings the uterus to a state of 'presensitivity' and this is characterized by closure of the uterine lumen with interdigitation of microvilli from opposite luminal surfaces. This state can be held for long periods but when oestrogen is also given the uterus becomes sensitive for a short period and then insensitive. Morphologically the latter state is characterized by very close apposition of the luminal surfaces with the loss of the microvillous structure. This is referred to as the second stage of closure and is usually reached after 4 or 5 days of treatment with low sensitizing doses of oestradiol, but with higher doses, which induce insensitivity to a decidual stimulus, it is reached prematurely.
THE SPLANCHNIC AND HEPATIC UPTAKE OF CORTISOL IN CONSCIOUS AND ANAESTHETIZED SHEEP
Authors: PATERSON J. Y. F. , HARRISON F. A.
Published: December 2008

The uptake of cortisol by the gastro-intestinal tract and by the liver was estimated in sheep by measurement of [3H]cortisol concentrations in portal and hepatic venous plasma during constant infusion of tritium-labelled cortisol, with simultaneous measurement of plasma flows.

The total splanchnic uptake of cortisol was 57 ± 4 (s.e.m.)% of the measured rate of cortisol secretion, 45% by the liver and the remainder by the gastro-intestinal tract. The splanchnic extraction of cortisol could be related to plasma flow, and was less efficient at higher flows. It could also be related to plasma cortisol concentration, and was more efficient at higher concentrations. The splanchnic uptake of cortisol was closely correlated with the flow of unbound cortisol into the region, and was 1·61 times that influx. There is therefore partial dissociation of plasma protein-bound cortisol during the splanchnic uptake.

About 25% of secreted cortisol is converted to cortisone at extrahepatic sites, and is removed from plasma by the liver.
SALURETIC ACTION OF ALDOSTERONE IN THE PRESENCE OF INCREASED SALT INTAKE AND RESTORATION OF NORMAL ACTION BY PROLACTIN OR BY OXYTOCIN
Authors: BURSTYN P. G. , HORROBIN D. F. , MANKU M. S.
Published: December 2008

The effects of aldosterone on sodium, potassium and water excretion during various treatment regimes were studied in six Merino ewes. Urine was collected from 12.00 to 14.00 h and from 14.00 to 16.00 h each day. Intravenous injections of either 1 ml isotonic saline or 500 μg aldosterone were given at 13.30 h and excretion during the second collection period compared with that in the first. When each animal was given a salt (NaCl) supplement of 80 mequiv./day by i.v. injection, aldosterone caused marked sodium retention with no effect on potassium. When salt supplements of 400 mequiv./day were given, aldosterone lost its sodium-retaining action in all animals and caused a marked saluresis with a small increase in potassium excretion in five sheep out of six. Injections of sheep pituitary prolactin or of oxytocin restored the sodium-retaining action of aldosterone in spite of a continued high salt intake. The animals gained very little weight when treated with 400 mequiv. salt alone but did gain significantly when treated with salt plus prolactin. The weight gain was rapidly lost when the prolactin and high salt intake were discontinued.
NUCLEIC ACID AND PROTEIN CONTENT IN THE PARS DISTALIS OF THE PITUITARY AND HYPOTHALAMUS OF THE FROG, RANA ESCULENTA: EFFECTS OF GONADECTOMY AND CAPTIVITY
Authors: RASTOGI R. K. , CHIEFFI G.
Published: December 2008

The protein, RNA and DNA content was measured in the pars distalis, hypothalamus and cerebral cortex of gonadectomized frogs (Rana esculenta) and compared with the levels in captive and in wild controls. Short-term (35 days) gonadectomy increased the weight of the pars distalis and also its RNA and protein content, whilst gonadectomy for a longer period (135 days, females only) depressed these parameters below control levels. In the hypothalamus, short-term gonadectomy increased the protein concentration, and long-term gonadectomy the RNA content. Captivity alone for 135 days caused a diminution in the weight and protein content of the pars distalis, although the various parameters showed an increase which correlated with the annual reproductive cycle. The DNA content (μg/mg tissue) of the pars distalis was similar in all groups suggesting that any weight changes were not due to changes in cell numbers. Neither gonadectomy nor captivity altered the nucleic acid and protein content of the cerebral cortex. The pars distalis weighed more in female frogs and contained more RNA and protein per mg.
LIPOLYTIC ACTIVITY OF HUMAN PITUITARY FRACTIONS ON HUMAN ADIPOSE TISSUE CELLS
Authors: STORRING P. L. , BURNS T. W. , FURNIVAL BRIDGET E. , HALES C. N. , LANGLEY P. , HARTREE ANNE STOCKELL
Published: December 2008

Attempts to isolate, free of thyroid-stimulating hormone (TSH), the peptide(s) responsible for the lipolytic activity of a fraction of acetone-dried human pituitary powder are described. It was not found possible to separate the lipolytic and TSH activities, even by isoelectric focusing which gave fractions consisting predominantly of single protein components. In the four lipolytic fractions isolated by electrofocusing, the two activities paralleled one another. It is therefore concluded that the TSH present is responsible for the lipolytic activity of this human pituitary fraction, though some evidence suggests that luteinizing hormone (LH), which is a minor contaminant, might also be lipolytic.

The minimum effective lipolytic concentration of the most potent fraction isolated was in the range 0·1–1·0 μg/ml. This is far in excess of plasma concentrations of TSH or LH encountered physiologically. Hence the lipolytic action of these molecules is unlikely to be of physiological significance.
SOME ASPECTS OF CHANGING BODY COMPOSITION OF MICE DURING SUCCESSIVE PREGNANCIES AND LACTATIONS
Authors: JOHNSON C. L.
Published: December 2008

Mice that had produced and reared three successive litters gained more weight than virgins. No differences in skeletal size were noted between the two groups but the mated mice accumulated a deficit of calcium and phosphorus. They also showed a rhythmical variation in body composition.
ERYTHROPOIETIN-INDUCED CHANGES IN PLASMA CALCIUM AND BONE MARROW MITOSIS IN THE RAT
Authors: HUNT N. H. , PERRIS A. D.
Published: December 2008

Subcutaneous injections of ovine erythropoietin preparations caused parallel increases in bone marrow mitotic activity and plasma calcium concentrations. These activities appeared to be a specific property of the erythropoietin molecule and were not due to an impurity. The increased mitosis and hypercalcaemia which followed erythropoitein injection in normal rats did not occur in the aparathyroid animal. Although a functional parathyroid gland was essential for the erythropoietin-induced changes, the mode of interaction between erythropoietin and the parathyroid gland remains to be established.
DISCHARGE PATTERNS OF SUPRAOPTIC AND PARAVENTRICULAR NEURONES IN RATS GIVEN A 2% NaCl SOLUTION INSTEAD OF DRINKING WATER
Authors: DYBALL R. E. J. , POUNTNEY PHILIPPA S.
Published: December 2008

The firing rates of antidromically identified neurones in the supraoptic and paraventricular nuclei were monitored in control animals, animals which had received a 2% Nacl solution instead of drinking water for 3 days and animals (recovery group) which after treatment were again allowed to drink tap water for 2 days. Treatment with NaCl depleted the pituitary stores of vasopressin and oxytocin and significantly increased the firing rate of antidromically activated neurones but not that of other hypothalamic neurones. In the recovery group the neurohypophysial stores of vasopressin and oxytocin had increased but were still significantly below control levels and the firing rates of the antidromically identified neurones were similar to those in control animals. Since the firing rates were increased by NaCl treatment and returned to control values when the treatment ceased it may be concluded that the excitation was due to stimulation of the neurosecretory neurones by the NaCl treatment.
THE EFFECT OF VASOPRESSIN (PITRESSIN) ADMINISTRATION ON SODIUM, POTASSIUM AND UREA EXCRETION IN RATS WITH AND WITHOUT DIABETES INSIPIDUS (DI), WITH A NOTE ON THE EXCRETION OF VASOPRESSIN IN THE DI RAT
Authors: LAYCOCK J. F. , WILLIAMS P. G.
Published: December 2008

The effect of the administration of vasopressin as subcutaneous Pitressin Tannate in oil (PTO) was studied in the Brattleboro rat. Rats with hereditary hypothalamic diabetes insipidus (DI), and rats heterozygous for this abnormality, were used. A minimum dose of 1000 mu. of PTO/24 h was necessary to restore the urinary volume and osmolality of DI rats to values comparable with those of heterozygous rats. The urinary excretion of antidiuretic activity in DI rats was shown to be related to the dose of PTO. Sodium and urea excretion, but not potassium excretion, were reduced by up to 50% in the DI rat. No comparable changes were produced in the heterozygous rat. The possible mechanisms of these actions of vasopressin are discussed.
THE BIOSYNTHESIS OF THYROXINE: INCORPORATION OF [U-14C]TYROSINE INTO THYROGLOBULIN BY MOUSE THYROID GLANDS IN VIVO AND IN VITRO
Authors: WAIN W. H.
Published: December 2008

The incorporation in vivo of [U-14C]tyrosine into 19S thyroglobulin by mice was achieved to a level of 2·85 c.p.m./μg. This level of incorporation was insufficient to permit the isolation of 14C-labelled iodinated tyrosines or residues. Isolated mouse thyroid lobes were used as an in-vitro system for the synthesis of 19S thyroglobulin. The lobes continued to incorporate 131I into 19S thyroglobulin for at least 48 h and this incorporation of iodine was specifically inhibited by propylthiouracil. The isolated mouse thyroid lobe in-vitro system was used to incorporate 14C-labelled amino acids into 19S thyroglobulin. [U-14C]Tyrosine was incorporated to a level of 1150 c.p.m./μg. Electrophoretic separations of enzymic hydrolysates of [14C]tyrosine-labelled 19S thyroglobulin showed the presence of [14C]tyrosine, [14C]monoiodotyrosine, [14C]di-iodotyrosine and [14C]thyroxine. The presence of [14C]tyrosine, [14C]monoiodotyrosine and [14C]thyroxine was demonstrated by chromatography of the eluates from the electrophoretic separations.

The results provide evidence for the utilization of tyrosyl residues within the thyroglobulin molecule for iodination and subsequent coupling to form thyroxine.
FORMATION OF PROGESTERONE AND PREGNENOLONE FROM [4-14C]CHOLESTEROL BY THE INTACT MID-TERM HUMAN FOETO—PLACENTAL UNIT PERFUSED IN VITRO
Authors: BAIRD D. T. , COCKBURN F. , GALBRAITH A. , KELLY R. , LIVINGSTONE J. R. B.
Published: December 2008

A system for perfusing in vitro the mid-term human pregnant uterus containing the entire foeto-placental unit is described. After termination by hysterectomy, circulation was established within 15 min by cannulation of the uterine arteries. In two experiments the foetal heart rate remained reasonably steady during the perfusion (107 and 127 min respectively). The rates of secretion of pregnenolone and progesterone into the uterine veins were within the range calculated for the period of gestation. Conversion of [4-14C]cholesterol to pregnenolone and progesterone was observed in both experiments although in neither could it account for the total secretion of progesterone.
THE INTERCONVERSION OF OESTRONE AND OESTRADIOL-17β AND THE CONCENTRATION OF OESTRADIOL-17β RECEPTORS IN CULTURED RABBIT UTERUS
Authors: RUSSELL SUSAN L. , THOMAS G. H.
Published: December 2008

The metabolism and uptake of [2,4,6,7-3H]oestrone and [2,4,6,7-3H]oestradiol-17β were examined in explants of rabbit uterus, vagina and skeletal muscle in organ culture for 1 and 3 days. Irrespective of whether the uterus was cultured in the presence of [3H]oestrone or [3H]oestradiol-17β, the tissue contained predominantly [3H]oestradiol-17β. This was also true for vagina, but muscle showed only a limited ability to interconvert the two oestrogens.

The oestradiol-17β binding capacity of cultured uterus was also determined, and was shown to decline rapidly over the first 24 h of culture.
THE PATTERN OF PROGESTERONE SECRETION BY THE AUTOTRANSPLANTED OVARY OF THE EWE IN RESPONSE TO OVINE LUTEINIZING HORMONE
Authors: COLLETT R. A. , LAND R. B. , BAIRD D. T.
Published: December 2008

The secretion of progesterone from the autotransplanted ovaries of five ewes was measured by a competitive protein-binding technique. Luteinizing hormone (NIH-LH-S14) increased the secretion rate of progesterone from the ovary when infused for 60 min via the ovarian artery at a rate of 1000 μg/h. The pattern of response in nine experiments was characterized by a significant increase in progesterone secretion which occurred 10–20 min after starting the infusion (150%). Between 30 and 60 min the secretion rate fell progressively towards the control values in spite of the continued infusion of LH. There was a further significant fall in the 30 min following cessation of LH. In three out of nine infusions there was a progressive increase in the ovarian blood flow throughout the infusion with maximal levels being found at the end of the 60-min infusion period.
HUMAN LUTEINIZING HORMONE IN MAN: STUDIES OF METABOLISM AND BIOLOGICAL ACTION
Authors: MARSHALL J. C. , ANDERSON D. C. , FRASER T. RUSSELL , HARSOULIS P.
Published: December 2008

Human luteinizing hormone (LH) was given by intravenous infusion to four normal male volunteers. The disappearance of immunoreactive LH from serum followed a single exponential decay, the mean half-life being 136 min. The effect on the testis of the infused LH was variable. Despite high serum LH levels being achieved, only one subject showed a clear increase in circulating 17β-hydroxyandrogen (17-OHA) levels, the other subjects showing little change in the immediate post-infusion period. All subjects had low 17-OHA levels in the period 24–36 h after the infusion. No consistent changes in serum follicle-stimulating hormone levels occurred during or after the infusion.

This suggests that other factors besides LH are necessary to produce maximal testosterone secretion by the testis, and may also be concerned in controlling the diurnal variation of testosterone.
SEQUENTIAL FOETAL—MATERNAL PLASMA CORTISOL LEVELS IN SHEEP
Authors: DROST M. , KUMAGAI L. F. , GUZMAN MARGARET
Published: December 2008

Chronic foetal—maternal cortisol interrelationships were studied in five time-dated pregnant ewes. Serial blood samples were obtained from ewe and foetus simultaneously for several weeks before and including parturition. Plasma cortisol was measured by both fluorometry and isotopic competitive protein binding. The data indicate that maternal cortisol levels are slightly higher than those in the foetus during the latter part of gestation until approximately 1 week before parturition. During the last week of gestation, especially 4–5 days before delivery, a marked increase in foetal cortisol levels was noted. Administration of amino-glutethimide to the foetus 1 week before delivery did not alter cortisol levels in either foetus or ewe. The results suggest that parturition in sheep is a culmination of events initiated by active foetal adrenocortical secretion.
INHIBITION OF OVULATION IN THE RAT BY INTRAHYPOTHALAMIC IMPLANTS OF AN ANTIOESTROGEN
Authors: BILLARD ROLAND , McDONALD P. G.
Published: December 2008

In order to determine the sites at which oestradiol exerts its positive feed back effect, double-walled cannulae containing the antioestrogen ICI 46,474 were implanted into the preoptic area, median eminence or anterior pituitary. Implants were made at different stages of the cycle and left in place for between 4 and 96 h. Implants in the preoptic area for 24, 48 or 96 h did not significantly inhibit ovulation. Implants placed in the median eminence for 24 h before the critical period significantly inhibited ovulation when compared with controls (P < 0·02). Implantation of antioestrogen in the anterior pituitary for a similar 24-h period was ineffective in blocking ovulation. However, when mixed with cocoa butter and implanted in the anterior pituitary the antioestrogen significantly inhibited ovulation (P < 0·02). The results show that by preventing the action of oestradiol on either the pituitary or the median eminence, ovulation may be inhibited. Ovulation was not affected by implants in the preoptic region which suggests that this area is not involved in the positive feedback action of oestradiol.
STIMULATORY EFFECT OF PROLACTIN ON INCORPORATION OF [3H]THYMIDINE INTO THE URINARY BLADDER OF THE FLOUNDER (KAREIUS BICOLORATUS)
Authors: HIRANO TETSUYA , HAYASHI SEIICHI , UTIDA SEIITIRO
Published: December 2008

Administration of prolactin for 3 or 5 days to the seawater-acclimatized flounder, Kareius bicoloratus, resulted in a significant increase in the incorporation of [3H]thymidine into the DNA fraction of the urinary bladder. When isolated bladders were incubated in isotonic Ringer solutions on both mucosal and serosal sides, net movement of water from mucosa to serosa decreased significantly after 3 or 5 daily injections of prolactin, whereas net absorption of sodium ions increased concomitantly; the time-course closely corresponded to that of thymidine incorporation. Tendency toward an increase in [14C]uridine and [3H]leucine incorporation was also observed in the urinary bladder after 5 daily injections of prolactin. However, incorporation of thymidine, uridine and leucine into the intestine was not affected at all by prolactin treatment for 5 days. All three isotopically labelled compounds were incorporated similarly into the urinary bladder and the intestine of control seawater flounders. Cell turnover in the urinary bladder is apparently as rapid as that in the intestine; specific stimulation of cell proliferation by prolactin may be an important factor in the induction of physiological changes in the bladder of the flounder.
A COMPARISON OF PROCEDURES FOR THE ISOLATION OF ADRENOCORTICOTROPHIN FROM HUMAN PITUITARY GLANDS
Authors: THOMAS MARJORIE B. , HARTREE ANNE STOCKELL , KNIGHT R. A. , RATCLIFFE J. G. , FURNIVAL BRIDGET E.
Published: December 2008

Two methods for the purification of corticotrophin from human pituitary glands have been assessed by two radioimmunoassays directed towards the C-terminal and N-terminal parts of the molecule, and by bioassay. One procedure, applied to small amounts of tissue, employs acid acetone extraction, oxycellulose adsorption and chromatography on CM-cellulose (CM-23). It is suitable for the small-scale purification of corticotrophin from pituitary glands but the losses associated with extracting low concentrations of hormone suggest that it would be inadequate for application to extrapituitary tissues and tumours. The starting material for the second procedure was a side fraction derived from the large scale extraction of protein hormones from whole pituitary glands. The purification employs oxycellulose adsorption, gel filtration on Sephadex G-50 and chromatography on CM-cellulose (CM-32). It yields sufficient highly potent corticotrophin for use as radioimmunoassay standard while conserving other scarce human pituitary hormones.
INDUCED OVULATION IN ALBINO RATS EXPOSED TO CONSTANT LIGHT
Authors: BROWN-GRANT K. , DAVIDSON J. M. , GREIG FENELLA
Published: December 2008

Adult female albino rats were exposed to constant illumination of moderate intensity for 55–65 days; at the end of this period more than 95% had no macroscopically visible luteal tissue in their ovaries and more than 90% were sexually receptive. In these animals ovulation was consistently induced by mating. The major component of the mating pattern responsible for the induction of ovulation was penile intromission. Mounting without intromission was much less effective and the occurrence or non-occurrence of ejaculation did not affect the incidence of ovulation. Non-sexual 'stressful' stimuli or the injection of progesterone also induced ovulation in about 50% of animals. However, adrenal progesterone was not required for either the maintenance of sexual receptivity or mating-induced ovulation since adrenalectomized rats exposed to constant light also mated and ovulated.

The time-course of the secretion of luteinizing hormone (LH), determined by radioimmunoassay of plasma LH, also indicated that mating had effects on LH secretion independent of any action of progesterone. LH concentrations were high at 40 min and maximal at 60 min after mating but decreased thereafter while following the injection of progesterone the levels rose gradually and remained high until at least 360 min after the injection. Sodium pentobarbitone administration had little effect on LH secretion induced by mating but blocked ovulation in some animals. Mating-induced ovulation was not invariably associated with increased activity of the thyroid gland but an increase did occur when the mating stimulus was prolonged.
THE PERSISTENCE OF PROGESTERONE SECRETION IN PREGNANT RATS AFTER HYPOPHYSECTOMY AND HYSTERECTOMY: A COMPARISON WITH PSEUDOPREGNANT, DECIDUOMATABEARING PSEUDOPREGNANT, AND LACTATING RATS
Authors: ROTHCHILD I. , BILLIAR R. B. , KLINE I. T. , PEPE G.
Published: December 2008

To test the hypothesis of Raj & Moudgal (1970) that luteinizing hormone (LH) is the essential luteotrophin during pregnancy in the rat, pregnant rats were hypophysectomized and hysterectomized on either day 12 or day 15 of pregnancy, and the changes in peripheral serum progesterone level measured. The serum progesterone level remained at approximately the day-12 value for 3 days after hypophysectomy and hysterectomy on day 12, but fell drastically and remained low after the same operation on day 15, or in pseudopregnant rats operated on on day 12, or after removal of the ovaries from pregnant rats on day 12. Oestrogen treatment increased the serum progesterone level slightly in the pregnant rats after hypophysectomy and hysterectomy, but not after ovariectomy; it had no effect in the pseudopregnant rats, with or without deciduomata, or in lactating rats nursing litters of seven to nine pups.

The corpora lutea stopped growing or slowly regressed soon after hypophysectomy—hysterectomy in all except the pregnant rats operated on on day 12 and treated with oestrogen, and in these growth was very slight. The luteal content of progesterone did not change for 3 days after hypophysectomy—hysterectomy on day 12 of pregnancy, and fell slightly thereafter. The metabolic clearance rate of progesterone was not significantly changed by hypophysectomy—hysterectomy.

It thus appears that true secretion of progesterone continues in pregnant rats for about 3 days after day 12 in the absence of the pituitary and placentas, but at a much lower rate than that found in intact, or in day-12 hypophysectomized pregnant rats (Pepe & Rothchild, 1972a). The placental luteotrophin thus seems to increase the rate of progesterone secretion in the absence of LH. The results do not seem to fit with the hypothesis that LH is essential for progesterone secretion.
ATTACHMENT TO THE LUTEAL PLASMA MEMBRANES: AN EARLY EVENT IN THE ACTION OF LUTEINIZING HORMONE
Authors: RAJANIEMI HANNU , VANHA-PERTTULA TAPANI
Published: December 2008

The distribution of 125I-labelled luteinizing hormone (LH) was studied by autoradiography of the murine pregnant ovary 10 min after intravenous administration. The grains in autoradiograms were localized around the luteal cells. The pregnant ovary showed the highest uptake of 125I-labelled LH 30 min after the injection. No similar accumulation of 125I-labelled follicle-stimulating hormone, 125I-labelled albumin or free 125I was obtained. The ribosomal fraction of the corpus luteum contained a slightly higher level of radioactivity than the other subcellular fractions after injection of 125I-labelled LH. Sucrose density gradient centrifugation of the luteal particle preparation resulted in an enrichment of radioactivity in particles containing Na+,K+-activated ATPase, a marker enzyme of the plasma membrane. These findings support the concept of plasma membrane binding as the initial event in LH action on the target tissue.
PREOVULATORY LEVELS OF LUTEINIZING HORMONE, THE CRITICAL PERIOD AND OVULATION IN RATS
Authors: GREIG FENELLA , WEISZ JUDITH
Published: December 2008

Plasma levels of luteinizing hormone (LH) were measured by radioimmunoassay in serial samples obtained from unanaesthetized, unrestrained rats by means of intracardiac cannulae (i) in relation to the critical period of neural facilitation (CP) during the afternoon of pro-oestrus and (ii) before and after an injection of sodium pentobarbitone given at specific times in relation to the critical period. Samples were also obtained by cardiac puncture before and after hypophysectomy carried out at specific times in relation to the CP. The effect of pentobarbitone or hypophysectomy on ovulation was also determined in the same animals. The CP as defined by pentobarbitone injection and hypophysectomy lasted from 15.00 to 16.00 h in the majority of rats. During this period the LH levels rose gradually above the basal value, and rose sharply thereafter to reach peak values at 17.00–18.00 h. Pentobarbitone given before the CP delayed the surge by 24 h, while its administration at the end of the CP caused an abrupt fall in plasma LH, indicating a reliance on the neurogenic stimulus both to initiate and to maintain the LH surge. LH levels reached immediately after pentobarbitone administration or hypophysectomy were correlated with the subsequent pattern of ovulation. Only a small increase in LH, amounting to about 14% of the peak values attained during the afternoon of prooestrus, was required for ovulation per se. This amount is similar to the small rise in circulating LH observed during the CP. The bulk of LH secreted during the 'pre-ovulatory surge' does not appear to be required for ovulation.
THE CONCENTRATION OF OESTRONE AND OESTRADIOL-17β IN SPERMATIC VENOUS BLOOD IN MAN
Authors: BAIRD D. T. , GALBRAITH A. , FRASER I. S. , NEWSAM J. E.
Published: December 2008

In nine men, spermatic and peripheral venous plasma was collected at operative repair of varicocele or inguinal hernia. The concentrations (ng/100ml plasma ± s.e.m.) of both oestradiol-17β (208 ± 28) and oestrone (36 ± 5) were higher than the corresponding values in peripheral venous blood (oestradiol, 3·2 ± 0·5; oestrone, 7·4 ± 1·5). These results confirm that both oestrogens are secreted directly by the testis.