bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF INTRAVENOUS AND INTRACAROTID INJECTIONS OF HYPERTONIC FLUIDS ON THE RELEASE OF MELANOCYTE-STIMULATING HORMONE FROM THE RAT POSTERIOR PITUITARY LOBE INCUBATED IN SITU
Authors: CYRKOWICZ A. , TRACZYK W. Z.
Published: December 2008

The posterior pituitary lobe of male rats under urethane anaesthesia was incubated in situ. The pituitary gland was exposed by the transpharyngeal approach. The posterior lobe remained in neural and partial vascular connexion with the hypothalamus, whereas the anterior lobe was entirely removed. Incubation fluid was collected and its melanophore-stimulating activity was assayed in hypophysectomized frogs. No effect was observed after the i.v. injection of 1 ml 120 μm-NaCl with 60 μm-CaCl2 or isotonic NaCl solution.

Hypertonic solutions of 5% NaCl and 25% glucose injected intravenously to the limit of 0·5% of the body weight, transiently enhanced the release of MSH from the posterior pituitary lobe by 66% (significant) and 15% (not significant) respectively. Intracarotid injection of 0·3 ml 5% NaCl solution resulted in the highest increase (95%) of MSH release.
LOCALIZATION OF PROLACTIN IN RAT KIDNEY TISSUE USING A DOUBLE-ANTIBODY TECHNIQUE
Authors: DONATSCH P. , RICHARDSON B.
Published: December 2008

A fluorescein-labelled double-antibody technique was used for the microscopical localization of ovine prolactin in kidney tissue of rats previously injected intravenously with 50 i.u. of the hormone at varying intervals before death.

Thirty seconds after the injection, the hormone could already be visualized in the lumina of the proximal tubules. After 2 min, discrete particulate fluorescence appeared on the brush border of the epithelium of the proximal tubules. Three minutes later prolactin was clearly localized in the apical portion of the cytoplasm of these cells as well as on the brush border. Ten minutes after the injection, the hormone appeared exclusively within the cell, highest concentrations being observed in the perinuclear region. After 20 min, however, the hormone appeared evenly distributed throughout the cytoplasm. The distribution of prolactin was in all cases confined to the proximal tubular region of the nephron.

The findings support the suggestion that the site of action of prolactin in the kidney is the epithelium of the proximal tubule. As prolactin was first visualized in the lumen of this portion of the nephron, it appears that the hormone gains access to these cells via the glomerular filtrate.
INFLUENCE OF SERUM FREE FATTY ACID LEVELS ON GROWTH HORMONE SECRETION IN LACTATING COWS
Authors: REYNAERT R. , DE PAEPE M. , MARCUS S. , PEETERS G.
Published: December 2008

The influence of intravenous injections or infusions of insulin (0·2 i.u./kg), propranolol (150 mg), 3,5-dimethylpyrazole (3 mg/kg), 3,5-dimethylisoxazole (0·08 mg/kg), glucose (0·5 g/kg), nicotinic acid (120 mg/kg), arginine (0·5 g/kg) or butyrate (0·5 mmol/kg) on plasma glucose levels, and on serum concentrations of growth hormone and free fatty acids of lactating cows was investigated. In all of these experiments we noted an increase in the level of growth hormone. This increase was not a direct consequence of alterations in the glucose concentration, since the growth hormone peak occurred both during a decrease (insulin, 3,5-dimethylisoxazole, nicotinic acid and butyrate tests), and during an increase of the glucose level (glucose, arginine and propranolol tests), whereas the glucose concentration remained unchanged during the 3,5-dimethylpyrazole experiments. However, in each instance a precipitous fall of the free fatty acid level was noted.

The glucose, growth hormone, and free fatty acid levels of lactating cows were not affected by either i.v. injection or infusion of saline.
METABOLIC CLEARANCE RATE, PRODUCTION RATE, AND MAMMARY UPTAKE AND METABOLISM OF PROGESTERONE IN COWS
Authors: HEAP R. B. , HENVILLE A. , LINZELL J. L.
Published: December 2008

Tracer kinetic techniques have been used to measure the production rate, metabolic clearance rate and mammary uptake of progesterone in six experiments on two Jersey cows. The cows were surgically prepared so that the carotid artery, jugular vein and mammary vein concentrations of progesterone, and udder blood flow, could be determined in conscious animals without anaesthesia or stress.

The mean production rate of progesterone was 173 ± 23·3 (s.e.m.) μg/min, with values ranging from 80 to 276 μg/min in pregnancy. The metabolic clearance rate was 22·5 ± 2·0 1/min, or 0·21 ± 0·025 1/min/kg metabolic body weight. The mammary uptake of progesterone was low, 3·1 ± 1·1 μg/min, and udder uptake accounted for about 3% of progesterone production rate.

During [3H]progesterone infusion, radioactivity was transferred from blood to milk, probably by diffusion down a concentration gradient. Progesterone accounted for more than 88% of the ether-soluble radioactivity recovered from milk.
EFFECT OF PROGESTERONE ON COLLAGEN BREAKDOWN AND TISSUE COLLAGENOLYTIC ACTIVITY IN THE INVOLUTING RAT UTERUS
Authors: HALME JOUKO , WOESSNER J. F.
Published: December 2008

Progestational agents were studied for their effects on collagenolytic activity and loss of collagen and wet weight from the involuting post-partum rat uterus. Administration of very large doses of progesterone (80–150 mg/day) significantly retarded uterine involution and loss of collagen. This was accompanied by a significant reduction in uterine collagenolytic activity. By 72 h post partum, uteri of rats treated with 150 mg progesterone/day had wet weights 30% above, collagen 85% above, and collagenolytic activity 45% below, those of the control uteri.

Similar effects were produced by 17α-acetoxy-6α-methylprogesterone at the same dosage levels. However, the progestational agent 6α-chloro-17α-acetoxypregna-4,6-diene-3,20dione acetate had no effect in this system.
EFFECT OF INTRAVENTRICULAR ADMINISTRATION OF NORADRENALINE ON WATER DIURESIS IN GOATS
Authors: MESSOM G. VANDEPUTTE-VAN , PEETERS G.
Published: December 2008

During water diuresis in conscious goats, noradrenaline (NA), its antagonists phentolamine, phenoxybenzamine and propranolol and also atropine were administered into the 3rd ventricle. The subsequent effects on water diuresis and on the excretion rates of Na+, K+ and Cl− were investigated.

Infusion of NA into the 3rd ventricle induced a strong and significant antidiuretic response and a decrease in the Na+: K+ excretion ratio; these effects were dose-dependent. High doses of NA produced a significant increase in urinary K+ excretion. Similar results were observed after i.v. administration of arginine-vasopressin.

Pretreatment with phentolamine injected into the 3rd ventricle produced a dose-dependent inhibition of the NA-induced antidiuretic effects. Phenoxybenzamine also blocked the response to NA but a dose-response relationship was not apparent. Atropine and propranolol did not block the response to NA.
RELATIONSHIP BETWEEN THE ENDOCRINE ENVIRONMENT WITHIN THE GRAAFIAN FOLLICLE AND THE SUBSEQUENT RATE OF PROGESTERONE SECRETION BY HUMAN GRANULOSA CELLS IN VITRO
Authors: McNATTY K. P. , SAWERS R. S.
Published: December 2008

The steroidogenic potential of granulosa cells harvested from human Graafian follicles containing varying concentrations of pituitary and steroid hormones was examined. The mitotic activity and production of progesterone by granulosa cells in vitro was found to be correlated with their hormonal environment at the time of harvesting. Only cells from follicles containing some FSH and high concentrations of oestradiol underwent spontaneous mitosis in vitro. However, mitosis could be induced by adding FSH and high concentrations of oestradiol to the culture, provided that the concentration of LH was low. Cells harvested from follicles containing LH, FSH and high concentrations of oestradiol secreted significantly more progesterone than cells from follicles which did not contain all three hormones.

It is suggested that after the initiation of follicular development by FSH, a long period of exposure (8–10 days) to both FSH and oestradiol is necessary before the maximum biosynthetic capacity of granulosa cells is achieved; this synthetic potential is then only realized under the influence of LH and prolactin. Premature exposure to LH inhibits both the mitotic activity and the steroidogenic potential of these cells.
CHANGES IN PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AFTER INJECTION OF PROGESTERONE AT VARIOUS TIMES DURING THE OVULATORY CYCLE OF THE DOMESTIC HEN (GALLUS DOMESTICUS)
Authors: WILSON SUSAN C. , SHARP P. J.
Published: December 2008

Changes in plasma LH concentrations after i.m. injections of 0·5 mg progesterone/kg at various stages of the ovulatory cycle were measured by radioimmunoassay. Four types of response were observed. (1) When the steroid was injected between 4 h after and 12 h before an ovulation, LH levels started to rise after 15–45 min and reached peak values within 90–120 min. The mean maximal incremental change in the level of LH was 1·58 ± 0·10 (s.e.m.) ng/ml (n = 37). (2) In contrast, when progesterone was injected 12–8 h before ovulation, i.e. immediately before a spontaneous pre-ovulatory LH surge, the resulting mean maximal incremental change in LH level, 0·79 ± 0·12 ng/ml (n = 9), was significantly smaller (P < 0·001). (3) If progesterone was injected 8–4 h before ovulation, i.e. when pre-ovulatory LH levels were rising, they immediately started to rise more rapidly and reached peak values within 45 min. The maximal incremental change in the level of LH under these circumstances, 2·34 ± 0·20 ng/ml (n = 12), was significantly greater (P < 0·001 in both cases) than the changes observed in the responses 1 and 2 described above. (4) Levels of LH generally showed no incremental change in response to injections of progesterone given 4–0 h before ovulation, i.e. when pre-ovulatory LH levels were falling.

It was concluded that the type of change in plasma LH levels induced by progesterone depended upon the stage of the ovulatory cycle at which the steroid was injected.
DEHYDROEPIANDROSTERONE-INDUCED THYROTROPHIN RELEASE DURING HEAT STRESS IN RATS
Authors: TAL E. , SULMAN F. G.
Published: December 2008

Six groups each of 12 male albino rats were reared from day 21 of life at temperatures of 23, 34 or 37 °C. While the rats survived for unlimited periods at 23 and 34 °C, the animals reared at 37 °C succumbed within 5 days to heat stress. The latter group, when injected s.c. or i.p. with 50 mg dehydroepiandrosterone (DHA)/kg/day were no longer affected by the heat. During this treatment thyroid epithelial cell height doubled, colloid decreased by 20%, connective tissue did not change, the basic metabolic rate decreased by 10% and rectal temperatures of the treated rats increased with the ambient temperatures. Body weight increased only slightly, pituitary TSH decreased by 25%, serum TSH increased by over 50%, thyroxine and 125I uptake increased by 200%. The survival of the DHA-treated rats was apparently secured by blocking the hypothalamic thermoreceptors.
OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN
Authors: BENTLEY P. J.
Published: December 2008

The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small.

Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased.

This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced.

The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present.

The physiological implications of these observations and the possible mechanisms involved are discussed.
EFFECTS OF PROSTAGLANDIN F2α AND E2 ON THE PRODUCTION OF PROGESTERONE BY HUMAN GRANULOSA CELLS IN TISSUE CULTURE
Authors: McNATTY K. P. , HENDERSON K. M. , SAWERS R. S.
Published: December 2008

Human granulosa cells with differing steroidogenic potentials were cultured in vitro. The effects of prostaglandin F2α (PGF2α) and PGE2 on the progesterone output and viability of these cells were investigated.

Prostaglandin F2α either alone or in combination with LH and FSH inhibited the production of progesterone over a wide range of concentrations (1–8000 ng/ml). However, the inhibitory effect of PGF2α was 200 times less effective when the cells were exposed to LH and FSH for 6 days before the addition of the prostaglandin. By contrast PGE2, at concentrations from 1 to 500 ng/ml, markedly stimulated the production of progesterone by granulosa cells, and this was not prevented by the addition of PGF2α. The degree of inhibition by PGF2α or stimulation by PGE2 was related to the biosynthetic capacity of the cells.

These studies suggest that PGF2α may act directly on the adenylate cyclase system of human granulosa cells by blocking its activation by LH, and they demonstrate that functional regression of the luteal cell can be induced independently of the blood vascular system.
STUDIES ON PLASMA CORTICOSTEROIDS IN THE RHESUS MONKEY (MACACA MULATTA)
Authors: SETCHELL K. D. R. , SHACKLETON C. H. L. , HIMSWORTH R. L.
Published: December 2008

The physiological regulation of the plasma corticosteroid concentration, measured by competitive protein-binding, was studied in female rhesus monkeys (M. mulatta) sedated with phencyclidine hydrochloride. Morning basal levels of plasma corticosteroids were found to be in the range 8·0–25·2 μg/100 ml, which is lower than that previously reported in this species. A circadian rhythm in plasma cortisol concentration was demonstrated. Prolonged sedation with phencyclidine was associated with a gradual increase in the plasma cortisol concentration. Synthetic α1–24 adrenocorticotrophic hormone given intravenously caused a rapid rise in plasma cortisol, the minimum effective dose was between 1 and 10 ng/kg body weight and the response was maximal after 1000 ng/kg. The administration of lysinevasopressin and the induction of hypoglycaemia by insulin were both followed by an increase in the plasma corticosteroid concentration. Metyrapone caused a decline in plasma 11-hydroxycorticosteroids and a concomitant increase in total corticosteroids measured by competitive protein-binding. It is concluded that the hypothalamic-pituitary-adrenal system in the rhesus monkey functions in a manner which is qualitatively and quantitatively similar to that of man.
EFFECT OF ACUTE INHIBITION OF ADRENOCORTICOTROPHIN SECRETION ON PLASMA CORTICOSTEROIDS IN THE RHESUS MONKEY (MACACA MULATTA)
Authors: SETCHELL K. D. R. , REES LESLEY H , HIMSWORTH R. L.
Published: December 2008

The half-life of plasma cortisol in the rhesus monkey (M. mulatta), determined by two methods, was about 130 min and longer than that in man; it was unaffected by administration of dexamethasone. Dexamethasone (5 mg, i.v.) immediately inhibited the secretion of ACTH from the monkey pituitary. The plasma half-life of NH2-terminal immunoreactive ACTH was found to be about 55 min which was much longer than the biological half-life. The adrenal synthesis of cortisol was inhibited by metyrapone which caused a prompt increase in the plasma concentration of ACTH and 11-deoxycortisol. The hypothalamicpituitary-adrenal system of the rhesus monkey sedated with phencyclidine hydrochloride responded rapidly to alteration in the level of steroids in the circulation.
PREOVULATORY CHANGES IN THE OVARIES DURING THE FIRST SPONTANEOUS PRO-OESTRUS IN THE RAT
Authors: OSMAN P.
Published: December 2008

Events in the ovaries during the first spontaneous pro-oestrus were compared with those in the adult rat. The occurrence of first spontaneous pro-oestrus was determined from vaginal smears after surgical opening of the vagina. Pubertal rats showed a remarkable increase in ovarian weight from 10.00 to 15.00 h on the day of pro-oestrus, which was absent in the adults. They also showed an earlier and more pronounced interstitial oedema. Dispersion of cumulus cells, resumption of meiosis and ovulation also occurred slightly earlier in pubertal rats. A distinct difference was found in the growth rate of follicles of ovulatory size, i.e. follicles of ≥ 500 × 105 μm3. At the first pro-oestrus these follicles showed a slower and less pronounced increase in size from 10.00 to 17.00 h compared with the adult follicles at this time, although this disparity was made up by a marked increase in growth from 17.00 to 24.00 h. The development of a new crop of follicles progressed similarly in the pubertal and adult animals. Follicular atresia seemed to progress more rapidly from 10.00 to 15.00 h in the pubertal animals compared with adults but from 15.00 h onwards no further differences were observed. The possible causal factors underlying the observed differences between the pubertal and adult animal are discussed.
AN UNUSUAL PATTERN OF TESTOSTERONE METABOLISM IN TISSUE ASSOCIATED WITH A KERATIN-FILLED CUTANEOUS CYST
Authors: HAY J. B. , HODGINS M. B.
Published: December 2008

Testosterone metabolism was studied in tissues associated with a keratin-filled cutaneous cyst. Instead of the 5α-reduced metabolites usually associated with skin steroid metabolism, considerable amounts of 5β-reduced steroids were found. These included 5β-androstane-3,17-dione, 17β-hydroxy-5β-androstan-3-one, and 5β-androstane-3β,17β-diol. This change in metabolic pattern is discussed.
GONADOTROPHIN AND STEROID LEVELS AROUND THE TIME OF FIRST OVULATION IN THE RAT
Authors: MEIJS-ROELOFS H. M. A. , UILENBROEK J. TH. J. , DE GREEF W. J. , DE JONG F. H. , KRAMER P.
Published: December 2008

Luteinizing hormone, FSH, prolactin, oestradiol and progesterone concentrations were measured by radioimmunoassay in the blood of female rats from 7 days before the first ovulation (the day of first ovulation is designated day 0) until the day after the second ovulation. Serum LH concentrations varied between 29 and 59 ng NIAMDD-rat-LH RP-1/ml from days −7 to −2. On the day preceding first ovulation (day − 1) a steep increase in serum LH was found between 13.00 h and 15.00 h reaching a maximal value of 2100 ng/ml at 17.00 h. Thereafter LH levels decreased to undetectable values (< 15 ng/ml). Serum FSH concentrations from days −7 to −2 varied between 108–154 ng NIAMDD-rat-FSH RP-1/ml; increased concentrations were found on the afternoon of day − 1 and on the morning thereafter (first oestrus) with a maximal value of 1150 ng/ml at 19.00 h on day − 1. On the day preceding the second ovulation (day +4) LH and FSH peaks were again found.

Prolactin concentrations on the days preceding first ovulation were generally low. A small rise was found nearing first ovulation (12·7 ng/ml, day −6; 23·9 ng/ml, day −2). On day − 1 a peak (118 ng/ml) was found at 15.00 h, similar to that found on day +4 in adult pro-oestrous rats.

Plasma progesterone concentrations also reached a peak value (50 ng/ml) on day − 1, at 17.00 h, preceded by concentrations between 3–5 ng/ml from days −6 to −2. Progesterone concentrations after the first ovulation showed a pattern characteristic of the adult cycle.

Plasma oestradiol levels were undetectable (< 10 pg/ml) from days −6 to −2; a clearly increased oestradiol concentration was found on day −1, reaching a value of 98 pg/ml. One and two days before the second ovulation, oestradiol levels rose again.

The differences and similarities between pubertal and adult pro-oestrous hormone peaks are discussed.
ENZYME ACTIVITY IN KIDNEY, ADRENAL AND GONADAL TISSUE OF RATS TREATED NEONATALLY WITH ANDROGEN OR OESTROGEN
Authors: GHRAF R. , HOFF H.-G. , LAX E. R. , SCHRIEFERS H.
Published: December 2008

A single injection of 300 μg oestradiol benzoate (OEB) or 1·25 mg testosterone propionate (TP) on day 1 of life led to significant changes in the activity of enzymes involved in steroid hormone metabolism in kidney, adrenal and gonadal tissues of adult rats. In the kidney, the enzyme activities of male rats reacted to OEB, but not TP, by the development of normal female levels. With one exception the enzyme activities of the kidney of female rats did not respond to either steroid. In the adrenal of both sexes 5α-reductase reacted to OEB, but not TP treatment, by a fourfold increase in activity. In the ovary all the enzymes investigated responded both to OEB and TP treatment by a fall in activity; 20α-hydroxysteroid dehydrogenase activity fell to undetectable levels. In the testis, OEB and TP treatment led to contrasting effects. With the exception of 5α-reductase all the enzymes tested in this organ responded to OEB by a rise in activity. Where TP had any effect, it produced a slight decrease in activity.
EFFECT OF l-DOPA ON MILK EJECTION AND PROLACTIN RELEASE IN LACTATING RATS
Authors: PRILUSKY J. , DEIS R. P.
Published: December 2008

The effect of l-DOPA on milk ejection and on prolactin release during 30 min of suckling was studied in lactating rats. Various doses of l-DOPA (1·25, 2·5, 5 and 10 mg/100 g body wt) were injected i.p. 30 min before the suckling period. Control rats were injected with 0·9% NaCl solution only. An inhibition of milk ejection proportional to the dose of drug administered was obtained. The dose of 10 mg completely blocked milk ejection but 1·25 mg had no effect. A normal milk-ejection response was obtained with a small dose of oxytocin injected immediately before nursing into mothers treated with 10 mg l-DOPA, indicating that the blocking effect was not due to a lack of mammary gland response. In control mothers, serum prolactin levels increased from 67·2 ± 25·9 (s.e.m.) to 950·3 ± 118·7 ng/ml after a 30 min suckling period. l-DOPA (5 and 10 mg) prevented the release of prolactin induced by suckling, but 1·25 and 2·5 mg l-DOPA had no effect. The results indicate that oxytocin and prolactin release induced by suckling in lactating rats is inhibited by an increase of catecholamines at the hypothalamic-hypophysial axis.
INTERRELATIONSHIPS OF PITUITARY AND PLASMA CORTICOTROPHIN AND PLASMA CORTICOSTERONE DURING ADRENOCORTICAL REGENERATION IN THE RAT
Authors: BUCKINGHAM JULIA C. , HODGES J. R.
Published: December 2008

Pituitary and plasma ACTH and plasma corticosterone were measured at various times after adrenal enucleation or adrenalectomy. The changes in ACTH could be inversely correlated with those in plasma corticosterone. They could also be prevented by maintenance therapy with the steroid. The results indicate that the corticosteroids control both the release and the synthesis of ACTH but that their effect is predominantly on the release of the hormone.
CORTICOSTEROID BINDING BY PLASMA PROTEINS AND THE EFFECTS OF OESTROGENS IN THE MARSUPIAL BRUSH-TAILED OPOSSUM, TRICHOSURUS VULPECULA (KERR)
Authors: THAN KHIN AYE , McDONALD I. R.
Published: December 2008

Using the techniques of equilibrium dialysis at 36 °C and gel filtration at 4 °C, a highaffinity, transcortin-like, corticosteroid binding system has been demonstrated in the blood plasma of the marsupial Trichosurus vulpecula.

The affinity constant for non-albumin binding was 4·018 ± 1·032 × 107 (s.d.) 1/mol for males and 4·046± 0·981 × 107 for females. The concentration of non-albumin binding sites was 1·82 ± 0·76 × 10−7 mol/l in males and 1·86 ± 0·57 × 10−7 mol/l for females. Oestrogen administration, sufficient to cause marked hypertrophy of the genital tract in the females, had no effect on the affinity constant or the concentration of the non-albumin binding sites in either males or females.

The general condition of the animals deteriorated during oestrogen administration and there were significant falls in the concentrations of albumin and cortisol in the blood plasma. In one animal which died during oestrogen treatment, the adrenal glands were significantly hypertrophied.
A POSSIBLE ROLE FOR OXYTOCIN IN SPERM TRANSPORT IN THE MALE RABBIT
Authors: SHARMA O. P. , HAYS R. L.
Published: December 2008

Administration of methallibure (50 mg/kg body weight, daily) to male rabbits resulted in a 45% reduction in sperm number in ejaculates obtained during the treatment period. Recovery occurred within 48 h after the last dose of methallibure. This decrease in sperm number did not occur when oxytocin (0·2 i.u./kg body weight) was administered simultaneously with methallibure. This suggests that methallibure prevents the release of oxytocin during ejaculation.
FURTHER EVIDENCE FOR HISTAMINE FACILITATING OESTROGEN ACTION IN THE UTERUS
Authors: CASTRO-VÁZQUEZ A. , GÓMEZ ELENA , DE CARLI D. N. , ROSNER J. M.
Published: December 2008

The effect of doses of oestradiol ranging from 0·0125 to 1·6 μg on the uterine weight of the spayed rat was studied 24 h after a single s.c. injection of the hormone. The lowest dose inducing a significant increase in uterine weight was 0·32 μg. When histamine dihydrochloride (50 mg) was simultaneously injected with the hormone, the effect of small doses of oestradiol (0·0125–0·2 μg) was significantly increased.

When oestradiol and histamine were administered for 3 successive days, the uterine weight of animals receiving 0·0125 μg oestradiol, if compared with untreated controls, was increased only in the histamine-treated group. When 0·05 μg oestradiol was administered, histamine did not modify the increase already produced by the hormone.

Spermidine and burimamide, two substances structurally related to histamine, increased [3H]oestradiol uptake by the spayed rat uterus. The latter (an antihistamine drug acting on H2-receptors) as well as pyrathiazine (a histamine releaser having antihistamine properties) decreased the effect of histamine on oestradiol uptake whereas diphenhydramine (an antihistamine drug blocking H1-receptors) did not modify it. Pyrathiazine was itself able to diminish oestradiol uptake.
MEASUREMENT OF CORTISOL, CORTISONE, 11-DEOXYCORTISOL AND CORTICOSTERONE IN FOETAL SHEEP PLASMA DURING THE PERINATAL PERIOD
Authors: THOMAS S. J. , WILSON D. W. , PIERREPOINT C. G. , CAMERON E. H. D. , GRIFFITHS K.
Published: December 2008

A method is described for the resolution and individual quantitation of cortisol, cortisone, 11-deoxycortisol and corticosterone in foetal sheep plasma. The steroids were extracted by solvent partition and separated by LH-20 Sephadex column chromatography. Radioimmunoassay was used for the measurement of 11-deoxycortisol and cortisone and competitive protein-binding for corticosterone and cortisol.

The relative levels of these steroids in the plasma of chronically catheterized sheep foetuses from 12 days before birth to term and then in the newborn lamb until 2 days of age are recorded.

Cortisol gradually increased from a basal concentration of between 0·5 and 3·0 μg/100 ml plasma between days 12 and 5 pre partum, and then rose rapidly to 10 μg/100 ml plasma during the last 5 days of pregnancy to reach a maximum during or just after birth. Two days post partum the levels had fallen to approximately 3 μg/100 ml plasma.

The mean value for 11-deoxycortisol between days 8 and 3 pre partum was 0·4 μg/100 ml plasma and increased in the final days before delivery to 1·0 μg/100 ml. Corticosterone initially showed slightly higher levels (∼ 1·5 μg/100 ml) in the earlier period of investigation but then fell during the immediate pre-partum period to 0·8 μg/100 ml. Cortisone was not detected at any stage of the investigations.

The relationship between levels of cortisol and 11-deoxycortisol in foetal plasma and myometrial contractility is shown. An increase in uterine activity was seen to occur at the time that cortisol levels were at their maximum. The 11-deoxycortisol values throughout this particular study remained low.

The results are discussed in relation to recorded levels in the adult and to previous studies in vitro with regard to changing steroid biosynthetic enzyme activity.
DISTRIBUTION OF NEUROSECRETORY GRANULES AMONG THE ANATOMICAL COMPARTMENTS OF THE NEUROSECRETORY PROCESSES OF THE PITUITARY GLAND: A QUANTITATIVE ULTRASTRUCTURAL APPROACH TO HORMONE STORAGE IN THE NEURAL LOBE
Authors: MORRIS J. F.
Published: December 2008

The distribution of neurosecretory granules in various anatomical compartments of neurosecretory axons of the neural lobe of the rat pituitary has been studied. Apart from the most anterior tip of the gland, where granules are largely restricted to undilated axons and a few 'swellings', the proportional compartmental storage of granules is essentially homogeneous for the rest of the gland: 13% of granules are found in undilated axons, 31% in axonal 'endings' (which contain microvesicles and abut the basement membrane) and 55% in axonal 'swellings' (which are devoid of significant numbers of microvesicles). These values indicate that the 'endings' contain a much greater proportion of the total number of granules stored in the neural lobe than would be predicted if the readily releasable pool of hormone were composed of all the granules in the 'endings'. Some further constraint on granule release either physiological or anatomical (e.g. the position of the granule in relation to the plasmalemma of the 'ending') must be operative.
EFFECT OF INTRA-UTERINE BEADS ALONE, OR COMBINED WITH OESTROGEN TREATMENT, ON UTERO-OVARIAN VENOUS PLASMA PROSTAGLANDIN F2α AND PROGESTERONE LEVELS IN THE GUINEA-PIG
Authors: BLATCHLEY F. R. , DONOVAN B. T. , POYSER N. L.
Published: December 2008

The presence of beads in the guinea-pig uterus caused premature regression of the corpora lutea, and a corresponding decrease in utero-ovarian venous plasma levels of progesterone, by days 9–10 of the oestrous cycle. If the beads were placed in one horn only, premature luteal regression occurred only in the adjacent ovary. Induced luteal regression was preceded by an increased release of prostaglandin F2α (PGF2α) from the uterine horns which contained the beads.

Oestradiol benzoate treatment of guinea-pigs carrying beads in one uterine horn overcame the unilateral effect and resulted in premature luteal regression in both ovaries. This was also associated with the early release of PGF2α from both uterine horns, though a difference in the timing of the release was apparent between the bead-containing (experimental) and control horns.
EFFECTS OF NEW MULTI-SITE HORMONE BLOCKERS ON THE FERTILITY OF MALE RATS
Authors: GOLDMAN A. S. , SHAPIRO B. H. , ROOT A. W.
Published: December 2008

The effects on the fertility of adult male rats of six new synthetic steroids: I, 3-cyano-5α-androst-l-en-17-one; II, the 17β-acetate form of I; III, 17β-hydroxy-5β-cyano-androstan-3-one; IV, 6-methylpregnenolone; V, 17β-hydroxy-17α-ethynyl-5β-cyano-19-norandrostan-3-one; and VI, 19-norspiroxenone (oestr-4-en-3-one-spiro-17α-2′-[tetrahydrofuran]) have been tested. After 6 weeks of treatment with daily doses of 5 mg (I, II, III), 15 mg (IV) or 10 mg (V, VI) only steroid VI blocked the completion of spermatogenesis and reduced the number of foetuses sired in at least five females/male. Steroid VI also diminished seminal vesicular, prostatic, testicular and epididymal weights. It inhibited the testicular enzymes, 3β-hydroxysteroid dehydrogenase-Δ4–5-3-oxosteroid isomerase system, 17α-hydroxylase, and C17–20 lyase markedly, but did not affect the adrenal dehydrogenase–isomerase system. It depressed, strikingly, testicular and serum levels of testosterone and 5α-dihydrotestosterone and reduced pituitary and serum levels of FSH and LH. Although marked depression of target organ weights also occurred with steroids II, IV and V, and reduction of androgen levels and LH in the circulation with III, IV and V, only VI was a potent blocker of male fertility with the exception of a slight block of the siring of viable foetuses by steroids IV and V. The major difference in site of action of steroid VI from the others was the depression of pituitary and serum levels of FSH along with a marked diminution of testicular content of both testosterone and 5α-dihydrotestosterone. 19-Norspiroxenone in the rat is a potent anti-oestrogen without inherent oestrogenicity and is anti-uterotrophic. Thus, VI may affect male fertility by virtue of its potent anti-oestrogenic action in the hypothalamus or testis.
RNA AND PROTEIN METABOLISM IN THE OVIDUCT AND ENDOMETRIUM OF THE EWE AT PRO-OESTRUS: REGULATION BY OESTRADIOL AND PROGESTERONE
Authors: MILLER B. G.
Published: December 2008

The effects on RNA and protein metabolism in the oviduct and endometrium at pro-oestrus of oestradiol and progesterone secreted during the oestrous cycle were examined, using the ovariectomized, hormone-treated ewe as a model system. Thirty ewes received hormone injections during a period of 13 days, according to schedules designed to simulate endogenous ovarian secretion of oestradiol and progesterone during the oestrous cycle. Hormone effects on RNA:DNA ratios and on rates of synthesis of protein and methylated RNA in vitro, as well as effects on oviducal and uterine weight, were examined.

The results obtained suggest that endogenous ovarian hormones have the following effects in the intact ewe. The secretion of oestradiol at pro-oestrus rapidly increases rates of synthesis of protein and methylated RNA, and mean cell content of RNA in both the endometrium and oviduct. Oestradiol secreted during the previous luteal phase of the oestrous cycle markedly increases mean cell content of RNA and amounts of protein and methylated RNA synthesis occurring in both tissues at pro-oestrus. In the endometrium, progesterone secreted during the luteal phase increases the RNA: DNA ratio, and probably also the amounts of protein and methylated RNA synthesized at pro-cestrus, but there are no significant interactions between the effects of oestradiol and progesterone. Progesterone had no effect on either the amounts or rates of synthesis of protein or methylated RNA in the oviduct. The results are discussed in relation to the hormonal regulation of physiological functions of the oviduct and endometrium during the first few days after the onset of oestrus.
OBSERVATIONS ON THE LOCALIZATION OF RECENTLY SYNTHESIZED CATECHOLAMINES IN CHROMAFFIN CELLS AFTER THE INJECTION OF l-[2,5,6-3H]DOPA
Authors: COUPLAND R. E. , KOBAYASHI S. , KENT CHRISTINE
Published: December 2008

The fate of l-[2,5,6-3H]DOPA, and the intracellular localization of its metabolic products dopamine, noradrenaline and adrenaline, have been determined by the simultaneous use of assay techniques following separation of amines by chromatography and light and electron microscopic autoradiography.

During the first 24 h after i.v. or i.p. injection of [3H]DOPA, synthesis of the above catecholamines occurred. Throughout this time the labelled amines were associated with chromaffin granules or immediately adjacent cytosol and not with either the Golgi complex or rough endoplasmic reticulum. Labelling of chromaffin granules occurred simultaneously throughout the cell and there was no evidence of regions containing recently labelled granules and others containing previously charged (older) granules. Adrenaline-storing cells took up [3H]DOPA and its products more rapidly and lost recently synthesized adrenaline more rapidly than noradrenaline-storing cells took up and stored their equivalent amines. This was in keeping with a more rapid turnover of catecholamines in adrenaline-storing elements.
COMPARISON OF THE REDOX BIOASSAY WITH OTHER ASSAYS FOR LUTEINIZING HORMONE
Authors: KRAMER ROSANNE M. , HOLDAWAY I. M. , CRIGHTON D. B. , McNEILLY A. S. , REES LESLEY H. , CHARD T.
Published: December 2008

The cytochemical (redox) bioassay for LH has been compared with established LH assays. Measurements made by redox bioassays were considerably lower than those made by radioimmunoassay in human female plasma samples obtained at mid-cycle. There was no apparent relationship between measurements on incubation media from cultures of sheep pituitary glands made by redox bioassay and the ovarian ascorbic acid depletion (OAAD) assay. After polyacrylamide gel electrophoresis of a crude extract of a human pituitary gland, redox LH measurements were lower than those of the OAAD assay and radioimmunoassay in the cathodal segments of the gel. By contrast, there was reasonable agreement between LH measurements made by radioimmunoassay and redox assay in cathodal fractions from gel electrophoresis of a purified pituitary LH preparation. Follicle-stimulating hormone, and the α- and β-subunits of LH depressed the response of intact LH in the redox assay; this might explain the relatively low levels of LH measured by redox assay in some of the experiments described. Which type of assay best reflects the biological activity of LH in man remains to be determined.
BLOOD CORTICOSTEROIDS IN AUSTRALIAN MARSUPIAL AND PLACENTAL MAMMALS AND ONE MONOTREME
Authors: ODDIE C. J. , BLAINE E. H. , BRADSHAW S. D. , COGHLAN J. P. , DENTON D. A. , NELSON J. F. , SCOGGINS B. A.
Published: December 2008

Peripheral blood corticosteroid levels were determined in nine species of Australian marsupial (Eastern grey kangaroo, black-tailed, Bennett's and pademelon wallabies, quokka, wombat, koala and Western native and tiger cats), one species of monotreme (echidna) and one placental Australian mammal (dingo). Animals were obtained or bled with minimal disturbance and came from areas considered to have adequate sodium content of the vegetation. Aldosterone, corticosterone, cortisol, 11-deoxycorticosterone and 11-deoxycortisol were measured and levels found to be similar to five introduced eutherian species (sheep, cow, dog, fox and man) with the exception of the koala and the wombat. Cortisol was the predominant corticosteroid, except in the koala, which produced corticosterone in relatively the greatest quantity, and the wombat which produced more 11-deoxycortisol. Steroid levels were generally low in the wombat. ACTH administered to the koala changed its pattern of corticosteroid secretion from predominantly corticosterone to cortisol. In the dingo, administration of ACTH caused rises in corticosteroid levels similar to those seen in most other eutherian mammals.
DISTRIBUTION OF PROSTAGLANDINS E2 AND F2α WITHIN THE FOETOPLACENTAL UNIT THROUGHOUT HUMAN PREGNANCY
Authors: WILLMAN EVE A. , COLLINS W. P.
Published: December 2008

The concentrations of prostaglandin E2 and F2α have been measured by radioimmunoassay in portions of cord, placenta, amnion, chorion, decidua and myometrium. The samples were obtained at defined periods of pregnancy, and the results have been compared with those obtained from the analyses of endometrial and myometrial tissue removed from women during the secretory phase of a menstrual cycle.

The results showed that during pregnancy the mean concentration of prostaglandin E2 was higher (27–518%) than the corresponding value for prostaglandin F2α in all tissues. At term the concentration of prostaglandin E2 (ng/100 mg wet weight of tissue, mean ± S.D.) was higher in the umbilical cord 5·54 ± 0·88), decidua (4·02 ± 1·78) and myometrium (4·19 ± 1·06), than in the amnion (2·25 ± 1·27), chorion (1·64 ± 0·63) or placenta (1·04 ± 0·25). During labour there was a significant rise (P < 0·0005, Student's `t' test) in the concentration in decidua (10·76 ± 4·45), and to a lesser extent (P < 0·05) in the myometrium (5·84 ± 2·65) and amnion (4·77 ± 2·51). The overall concentration in decidua during the first trimester (3·09± 1·02) was significantly lower (P < 0·005) than in endometrial tissue (16·82 ± 10·13). The concentration was lower in myometrial tissue from non-pregnant subjects (2·90 ± 2·21), than in the corresponding tissue removed at term (4·19 ± 1·06) or during labour (5·84 ± 2·65).

The results for prostaglandin F2α showed a similar pattern, but the values were significantly lower in the umbilical cord, and the percentage changes in concentration in the decidua and myometrium were of a higher magnitude.
BILATERAL ADRENALECTOMY OF LAMBS IN UTERO: EFFECTS ON MATERNAL HORMONE LEVELS AT INDUCED PARTURITION
Authors: FLINT A. P. F. , ANDERSON ANNE B. M. , GOODSON JANE D. , STEELE PENELOPE A. , TURNBULL A. C.
Published: December 2008

Progesterone, 17α,20α-dihydroxypregn-4-en-3-one, androstenedione, total unconjugated oestrogen and oestrone sulphate have been measured by radioimmunoassays in maternal utero-ovarian venous, maternal peripheral venous and/or foetal posterior vena caval plasma from six sheep bearing bilaterally adrenalectomized lambs, in which premature parturition was induced by administration of glucocorticoid. Three of the ewes were ovariectomized, and in one of these three animals the foetal testes were also excised, at the time of foetal adrenalectomy. Adrenalectomy was judged to be complete on the basis of plasma cortisol levels in the neonatal lambs, and by examination of the site of ablation at necropsy. In all cases foetal administration of glucocorticoid led to the onset of labour, and lambing, and in all animals the hormonal changes preceding parturition were indistinguishable (either qualitatively or quantitatively) from the changes observed in animals carrying intact lambs. Since therapy with glucocorticoid alone successfully compensates for ablation of the foetal adrenal cortex, it is suggested that glucocorticoid is the only adrenal product required to cause parturition, and that foetal adrenal secretion of androgens may be unnecessary.
EFFECTS OF EXOGENOUS DEHYDROEPIANDROSTERONE SULPHATE ON VARIOUS ENZYMES AND ON STEROID METABOLISM IN THE GUINEA-PIG
Authors: BERGHEIM ECKART , OERTEL G. W.
Published: December 2008

Treatment of male guinea-pigs daily with an oral dose of 2 mg dehydroepiandrosterone (DHA) sulphate/100 g body weight for 2 weeks significantly reduced the glucose-6-phosphate dehydrogenase (G-6-PDH) activity of erythrocytes, liver, kidney and testis. Lactate dehydrogenase activity in plasma also decreased, but l-aspartate: 2-oxoglutarate aminotransferase (GOT) and l-alanine: 2-oxoglutarate aminotransferase (GPT) activity in plasma remained unaffected. In liver and kidney, however, a significant rise in GOT and GPT was observed.

A 2- to 3·7-fold increase of C19-steroids was observed in plasma, liver and kidney. In extracts of liver and kidney more than 60% of steroids were isolated from the sulphatide fraction. Only minor changes were detected in the metabolic pattern of C19-steroids, 17-hydroxysteroids prevailing in the free and sulphatide fractions, while 17-oxosteroids predominated in the sulphate and glucuronide fractions.

A slight rise of cyclic AMP concentrations in liver and kidney tissue was attributed to the inhibition of phosphodiesterase by the DHA/G-6-PDH system.
REGULATION BY TESTOSTERONE AND SERUM PROTEIN OF DNA SYNTHESIS IN THE DEVELOPING EPIDIDYMIS OF THE RAT
Authors: MAJUMDER G. C. , TURKINGTON R. W.
Published: December 2008

Rates of DNA synthesis were measured as an index of cellular proliferation during the pubertal development of the rat epididymis. A highly reproducible pattern of DNA synthesis was defined by (1) a prepubertal, testosterone-insensitive peak of DNA synthesis at 25 days; (2) a dramatic decrease in DNA synthesis with the onset of puberty; (3) a major burst of testosterone-dependent synthesis peaking at 40 days in the head of the epididymis and at 40–60 days in the tail; (4) a fall to low levels as the adult organ weight was attained. An organ culture system was defined and utilized to analyse further the hormonal dependence of DNA synthesis in the epididymis. Testosterone and dihydrotestosterone failed to activate DNA synthesis at any stage of development in vitro. DNA synthesis was stimulated 100–300% by insulin at supra-physiological concentrations and by protein serum factor(s) at physiological concentrations. The serum activity was stable to heat treatment at 60 °C, destroyed by heating at 70 °C, and was present in the sera of hypophysectomized animals. These results indicate a primarily 'permissive' role for the action of testosterone on DNA synthesis in the epididymis: testosterone acts to permit the expression of a developmental 'programme' of cell proliferation which is activated by specific protein(s) in serum.
EFFECT OF ALDOSTERONE ON LITHIUM PERMEABILITY OF RAT COLON MUCOSA
Authors: DOLMAN DIANA , EDMONDS C. J. , SALAS-COLL C.
Published: December 2008

The effect of aldosterone on the ionic composition of colonic epithelial cells and on lithium absorption rate was studied by experiments on rats in vivo. Aldosterone considerably increased the rate of sodium absorption without measurably altering the sodium and potassium content of the epithelium. Aldosterone did not alter the electrical resistance of the tissue. With lithium in the lumen, the net sodium fluxes in the colon were similar in normal and aldosterone-stimulated rats but the rate of diffusion of lithium across the epithelium was greater in the aldosterone-stimulated group. The amount of lithium accumulating in the epithelial layer was also considerably increased by aldosterone stimulation. Aldosterone appears to increase the permeability of the mucosal (luminal) barrier allowing increased entry of lithium into the colonic epithelial cells.
EFFECT OF CYPROTERONE ACETATE ON ANDROGEN-DEPENDENT SYNTHESIS OF α2u GLOBULIN IN RATS
Authors: ROY A. K.
Published: December 2008

Cyproterone acetate (CA, 2·5 mg/100 g body wt) inhibited androgenic induction of α2u globulin in spayed rats. In mature male rats, which normally produce α2u globulin, ten daily injections of CA did not inhibit synthesis of this protein. Long-term treatment of mature male rats (two injections every week for 12 weeks) showed only slight inhibition of α2u synthesis after 10 weeks of CA treatment. CA also failed to compete with 5α-dihydrotestosterone for the cytosol androgen-binding protein of male rat liver. The inhibitory effect of CA on the primary induction of α2u globulin in the spayed rat and its lack of effect on continued synthesis of this protein in maximally induced mature male rats are consistent with the hypothesis of a two-step mechanism for androgenic regulation of α2u synthesis, an initial CA-sensitive step followed later by a CA-insensitive step.
SUSTAINED EFFECTS OF SYNTHETIC OVARIAN STEROIDS ON RAT MYOMETRIAL CONTRACTILITY
Authors: PARKINGTON HELENA C. , LIPTON A.
Published: December 2008

Ovariectomized rats were given a single dose of synthetic oestrogen or progestogen, or both combined.

On selected days after treatment one rat from each treatment group was killed and myometrial contractility in response to spasmogens was measured isometrically in isolated tissue baths. Contractility persisted at a low level after ovariectomy without steroid replacement (controls) for the 60 days of the experiment.

The powerful potentiating action of oestrogen reached a maximum in about 10 days and sustained a high level thereafter.

Progestogen treatment did not influence contractility to a significant degree when compared with saline, except that the contractions were sometimes of higher frequency and more irregular in size.

There was a less powerful potentiating action on contractility with combined oestrogen and progestogen treatment than with oestrogen alone. It reached a maximum in 4 days and declined more rapidly than with the oestrogen-treated preparation but was still vigorous for up to 30 days.