bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE ACTIVITY OF THE THYROID GLAND OF POECILIA DURING THE GESTATION CYCLE
Authors: BROMAGE N. R. , SAGE M. 
Published: December 2008

SUMMARY
The activity of the thyroid glands of Poecilia reticulata was studied by interferometry of the colloid and by histological methods. Interferometric measurements of dry weight per unit area of colloid in sections provided a more sensitive criterion of thyroid activity than histological observation. Active glands from thiourea-treated animals showed a reduction of dry weight per unit area while inactive glands from thyroxine-treated animals showed an increase as compared with control animals. Thyroid glands cultured in a thyrotrophin-containing medium showed a decrease in dry weight per unit area as compared with control glands.
Females during the gestation cycle showed a peak in thyroid activity during the first third of the 24-day cycle. Minimal activity occurred during the second third and intermediate activity during the last third of the cycle at which time the level of activity was much more variable than during the earlier two-thirds of the cycle. Females in which fertilization of the ova had not occurred had inactive although variable thyroid glands, which did not show the cycle of activity seen in the fertilized females. The cycle of thyroid activity is related to the reproductive cycle. It involves a peak in activity at the start of the cycle. The relationships between the thyroid and reproductive systems are discussed.
THE EFFECTS OF GONADAL HORMONES ON THE LEVELS OF PITUITARY LUTEINIZING HORMONE IN THE DOMESTIC FOWL
Authors: HEALD P. J. , ROOKLEDGE K. A. , FURNIVAL B. E. , WATTS G. D. 
Published: December 2008

SUMMARY
Groups of laying mature domestic fowl were injected i.m. with varying doses of either oestradiol benzoate, testosterone propionate or progesterone and were killed at random intervals throughout the day without reference to any specific point in the ovulatory cycle. Luteinizing hormone (LH) was assayed in the anterior pituitaries of each group. It was shown that oestradiol in doses calculated to be equal to or above the physiological level, increased pituitary LH without necessarily affecting the laying cycle. Testosterone had no significant effect on pituitary LH, while progesterone significantly increased pituitary LH at doses which had no apparent effect upon ovulation. Doses effective in the laying hen had little or no effect on the pituitary content of LH in immature birds. The results in the laying hen are in harmony with the concept previously proposed, by which changes in the levels of circulating plasma oestrogens may regulate the ovulatory pattern of the fowl by inhibiting release of pituitary LH.
THE UPTAKE OF SIMULTANEOUSLY ADMINISTERED [3H]OESTRADIOL AND [14C]PROGESTERONE BY DIMETHYL BENZANTHRACENE-INDUCED RAT MAMMARY TUMOURS
Authors: MOBBS BETTY G. 
Published: December 2008

SUMMARY
The uptake of simultaneously injected [3H]oestradiol and [14C]progesterone by dimethylbenzanthracene-induced mammary tumours in the rat was compared with that obtained when oestradiol was injected alone. Progesterone was not taken up and/or retained by hormone-responsive adenomata and fibroadenomata to the same extent as oestradiol, and it is suggested that the mechanism of action of progesterone is different from that of oestradiol and does not involve retention by the target tissue. Progesterone did not affect the uptake of oestradiol by hormone-responsive adenomata and fibroadenomata but there was a tendency for progesterone to increase the uptake of oestradiol and/or its free steroid metabolites by hormone-unresponsive adenomata. This could be due either to the timing of the experiments or to progesterone altering the equilibrium between oestradiol levels in blood and hormone-unresponsive tumours.
ENHANCEMENT OF GONADOTROPHIN ACTIVITY BY A RAT CEREBRAL TISSUE FRACTION
Authors: HOPKINS T. F. 
Published: December 2008

SUMMARY
The gonadotrophin-enhancing effect of RCF-2 (prepared from aqueous extracts of rat cerebral tissue) was evaluated in several species of laboratory animals. RCF-2 alone did not induce any discernible gonadal response. Superovulation in immature rats treated with pregnant mare serum (PMS) or a combination of PMS and human chorionic gonadotrophin (HCG) was significantly increased by RCF-2. Ovulation in intact PMS-treated rats was increased to 84–127% above the response of controls. Hypophysectomized or intact rats treated with PMS + HCG shed 34–53% more ova when they were treated with 0·2 mg. RCF-2.
An almost maximal uterine weight response was found in immature mice treated with RCF-2 in combination with subminimally effective doses of HCG. RCF-2 neither induced ovulation in post-partum rabbits nor in PMS-treated rats in which the release of luteinizing hormone was blocked. The results of these studies suggest that fraction RCF-2 does not act centrally to evoke a release of gonadotrophins but probably has a direct ovarian effect.
A POSSIBLE MECHANISM OF THE OVULATION-INHIBITING EFFECT OF CHLORMADINONE ACETATE IN THE RAT
Authors: DÖCKE F. , DÖRNER G. , VOIGT K.-H. 
Published: December 2008

SUMMARY
To study the mechanism of the ovulation-inhibiting effect of chlormadinone acetate, different quantities of this progestogen were implanted into one or both ovaries of dioestrous female rats. Introduction of the subcutaneously effective dose into one ovary suppressed ovulation in both, but implantation of half of this quantity did not influence spontaneous ovulation. On the other hand, 1/100 of the subcutaneously effective dose, implanted into the medio-basal hypothalamus or the anterior pituitary of adult dioestrous female rats, and of prepubertal females simultaneously injected with oestradiol benzoate, inhibited spontaneous and oestrogen-induced ovulations respectively. In juvenile rats the main site of action was the median eminence—anterior pituitary region. Chlormadinone was then implanted into the anterior hypothalamus or the anterior pituitary of adult dioestrous rats, and the median eminence was electrically stimulated during the 'critical period' in pro-oestrus. Since implants in the adenohypophysis prevented ovulation whereas implants in the anterior hypothalamus did not, a hypophysial site of action is suggested. On the basis of these results and of former findings on the action of oestrogens in ovulation, a hypothesis involving a competitive antagonism between oestrogen and progestogen at the hypophysial level is advanced to explain the acute ovulatory effects of these steroids.
HORMONAL REGULATION OF CELL DIVISION IN EPITHELIAL AND CONNECTIVE TISSUES OF THE MOUSE UTERUS
Authors: MARTIN L. , FINN C. A. 
Published: December 2008

SUMMARY
Progesterone treatment significantly altered the response of the mouse uterus to oestradiol-17β. Oestradiol given alone produced many mitoses in the luminal and glandular epithelia but not in the connective tissue stroma. After treatment with progesterone this pattern was reversed and oestradiol produced many mitoses in the stroma but few in the epithelia. Production of stromal cell division was influenced by the dose of progesterone and by the period of treatment; a single day of treatment greatly reduced the numbers of epithelial mitoses produced by oestradiol but did not greatly increase stromal mitosis. At least 3 days' treatment was necessary for a maximal stromal response.
Doses of oestradiol sufficient to inhibit implantation and deciduomata production did not reverse the stromal response but did overcome, in part, the progestational suppression of epithelial mitosis, producing large numbers of mitoses in the luminal but not in the glandular epithelium.
AROMATIZATION IN VITRO OF NEUTRAL STEROIDS BY BOVINE OVARIES
Authors: PATWARDHAN VASANT V. , ROMANOFF E. B. 
Published: December 2008

SUMMARY
The capacity of bovine ovaries to aromatize neutral C19 steroids in vitro was studied by perfusion and incubation techniques.
[4-14C]Androstenedione and [4-14C]dehydroepiandrosterone were infused, in separate experiments, into ovaries perfused in vitro and the formed oestrogens were isolated from the venous perfusates. The extent of aromatization of the infused substrate was found to be very small in all the perfusion experiments and was not enhanced by simultaneous infusion of gonadotrophins.
In incubation studies, minces of whole follicular ovary, whole luteal ovary, corpus luteum and stromal tissue were incubated with [4-14C]androstenedione. The incubates were processed for isolation of oestrone (OE1) and oestradiol-17β (OE2). Both the follicular and the luteal ovaries aromatized the substrate to OE2, although the extent of aromatization varied in different experiments. Formation of OE1 was indicated but not proved. The corpus luteum tissue did not aromatize the C19 substrate and the stromal tissue also showed a comparative lack of activity in this respect as compared with the whole luteal ovary.
The significance of these findings is discussed.
MAINTENANCE OF PREGNANCY AFTER IMPLANTATION IN HYPOPHYSECTOMIZED OR OVARIECTOMIZED MICE TREATED WITH PHENELZINE DERIVATIVES
Authors: JAITLY K. D. , ROBSON J. M. , SULLIVAN F. M. , WILSON CATHERINE 
Published: December 2008

SUMMARY
Some derivatives of phenelzine have been shown to interrupt pregnancy in mice, when given after implantation, i.e. on days 7–10. Pregnancy can be maintained in mice treated with these compounds and in mice hypophysectomized on day 7 by administration of suspensions of whole mouse pituitaries, of human chorionic gonadotrophin or of progesterone given with a basic concentration of oestrogen. Prolactin was ineffective in maintaining pregnancy. The action of the phenelzine derivatives could also be reversed by 0·5–1 μg. luteinizing hormone and by 0·05 μg. oestradiol. The compounds antagonized the action of progesterone in maintaining pregnancy in ovariectomized mice and this indicates that they act on the uterus. There may be, in addition, a more central action, e.g. on the ovary or on the pituitary but this would be masked by the peripheral (i.e. uterine) effect.
THE EFFECTS OF OESTRADIOL-3,17β ON TUBAL TRANSPORT IN THE LABORATORY MOUSE
Authors: HUMPHREY K. W. 
Published: December 2008

SUMMARY
Pregnant mice received varying doses of oestradiol on days 1–3 of pregnancy, or on day 1 or day 2 only. The effects of oestradiol on tubal transport depend largely on the time of treatment rather than the dose of oestradiol. Treatment with 1·6 μg. on day 1 when the ova were still in the ampulla caused retention of all ova in the oviduct until day 4—many of these tube-locked ova were retained in the ampulla, apparently because of prolonged closure of the ampulla-isthmus junction. Treatment with 0·4 μg. on day 2 when all ova were in the isthmus caused premature entry of ova into the uteri and reduced the recovery of ova by over 50%. Ligation of various parts of the tract and ovum transfer studies showed that this loss of ova is due to accelerated transport from the isthmus to the uterus and vagina. These effects on tubal transport were not reversed by concurrent administration of progesterone. Tubal retention was associated with delayed development of the blastocoele but these ova implanted normally after ovum transfers.
ACIDIC URINARY METABOLITES OF PROGESTERONE: STUDIES ON THE PREGNANT RABBIT
Authors: ALLEN J. G. , THOMAS G. H. 
Published: December 2008

SUMMARY
Indirect evidence is presented which suggests that the same acidic metabolites are obtained from the hydrolysed urine of the pregnant rabbit as from the non-pregnant animal injected with labelled progesterone. The acidic urinary metabolites were characterized by conversion with borohydridebismuthate to neutral aldehydes, which were then chromatographed on SE-30 and QF-1. In four rabbits the urinary excretion of the aldehydogenic metabolites and of pregnanediol, before and after mating, was parallel; the highest values were obtained in the 24 hr. after the coital stimulus.
THE INFLUENCE OF GONADAL HORMONES ON THE UPTAKE OF [14C]ACETATE BY LIVER LIPID FRACTIONS IN THE IMMATURE MALE CHICK
Authors: BALNAVE D. 
Published: December 2008

SUMMARY
Six-week-old cockerels with an equalized food intake and receiving by injection oestrogen, androgen or progesterone were used in an investigation on the influence of the gonadal hormones on the rate of uptake of [14C]acetate into liver lipid fractions.
The results obtained indicate that oestrogen was the only one of these hormones that affected the overall lipid composition of the liver significantly. However, although in all these treatments most of the label was incorporated into the triglyceride fraction, both testosterone and progesterone showed incorporation-time patterns which differed substantially from those obtained in control and oestrogen-treated birds. There was a very rapid incorporation of label into the liver lipids of the testosterone and progesterone-treated birds and the amount incorporated was greater than the maximum incorporation obtained at a later time in the control or oestrogen-treated birds. It is possible that a different biosynthetic pathway is utilized in the formation of triglycerides in testosterone and progesterone-treated birds than in oestrogen-treated birds.
The results indicate also that although testosterone and progesterone do not influence the overall lipid composition of the liver, they exert a significant influence on metabolic processes involving the synthesis and degradation of liver lipids.
STIMULATION OF SYNTHESIS OF GLYCOPROTEIN ENZYMES IN THE RAT UTERUS BY OESTRADIOL
Authors: DUGAN F. A. , RADHAKRISHNAMURTHY B. , RUDMAN R. A. , BERENSON G. S. 
Published: December 2008

SUMMARY
Glycoproteins from immature and immature, oestrogen-stimulated and adult rat uteri were isolated and analysed by chemical and gel electrophoretic methods. Esterase, acid phosphatase, alkaline phosphatase and peroxidase activities were found. Changes in electrophoretic mobilities of certain enzyme bands in polyacrylamide gel were also observed after hydrolysis of the preparations with neuraminidase. These latter observations and chemical analyses provide additional evidence of the carbohydrate nature of the enzymes. The influence of 17β-oestradiol on immature rat uteri caused a significant increase in total protein and sialic acid per uterus compared with controls. Oestrogen treatment also resulted in an increase in the total activity of esterase and acid and alkaline phosphatases per uterus, but there was no increase in specific activities. Observations of electrophoretic patterns of glycoprotein preparations from untreated and oestrogen-stimulated, immature uteri did not show the evolution to a more adult pattern by oestrogen stimulation. These studies show that stimulation with oestrogen increases the synthesis of glycoprotein in the immature rat uterus. Factors which are involved in the more intricate control of glycoprotein biosynthesis need to be elucidated.
MORPHOLOGICAL AND BEHAVIOURAL EFFECTS OF AN 'ANTIANDROGEN' IN MALE RATS
Authors: BEACH F. A. , WESTBROOK W. H. 
Published: December 2008

SUMMARY
Male rats injected with 10 mg. cyproterone acetate daily for 28 days were given weekly mating tests with receptive females. At the conclusion of testing the animals were killed and the testes and seminal vesicles were weighed. These organs and the glans penis were then prepared for microscopic analysis. The experimental treatment had no detectable effect upon copulatory behaviour nor upon the testis or the cornified papillae in the integument of the glans penis. The seminal vesicles of treated males appeared to be non-secretory and were lighter than those of control rats but heavier than the vesicles of untreated castrates. It is concluded that although cyproterone acetate partially blocked the action of endogenous androgen on the seminal vesicles it had neither a blocking effect on the penile papillae nor on the central nervous mechanisms which mediate mating responses.
THE ROLE OF OESTROGEN IN THE INDUCTION OF OVULATION IN THE GONADOTROPHIN-TREATED IMMATURE RAT
Authors: GRAYBURN J. A. , BROWN-GRANT K. 
Published: December 2008

SUMMARY
The effects of different doses of pregnant mare serum gonadotrophin (PMS) were examined in 29-day-old immature rats; a dose great enough to produce follicles capable of ovulating in response to the additional injection of human chorionic gonadotrophin (HCG) 56 hr. later in the majority of animals also caused significant oestrogen secretion as judged by uterine weight. Maximal uterine growth resulted from doses of PMS that led to a significant incidence of 'spontaneous' ovulation. In contrast, administration of ovine follicle-stimulating hormone (FSH) resulted in the ripening of large numbers of follicles with much less evidence of oestrogen secretion; 'spontaneous' ovulation did not occur in FSH-treated animals but ovulation could be induced by additional treatment with oestrogen and progesterone in combination but not by either steroid alone. Previous exposure to oestrogen appears to be necessary for the facilitatory action of progesterone on luteinizing hormone release to be demonstrable and the FSH-primed immature rat is a convenient preparation to study this interaction.
A STUDY OF BLASTOCYSTS DURING DELAY AND SUBSEQUENT IMPLANTATION IN LACTATING MICE
Authors: McLAREN ANNE 
Published: December 2008

SUMMARY
Blastocysts were studied on the 5th and 8th day of pregnancy in lactating mice, in the fresh state, flushed from the uterus, in squash preparations and in serial sections. At the earlier period some mitosis was observed. Tritiated thymidine incorporation studies gave some evidence of DNA synthesis on the 5th and 6th days of pregnancy. By the 8th day the blastocysts were longer, contained more cells, and mitosis had ceased. They were located at the anti-mesometrial end of the uterine lumen, closely apposed to the uterine epithelium, and with their long axes parallel to the long axis of the uterine horn. Implantation could be induced, either by the removal of the litter, or by the injection of an appropriate dose of oestrogen on the 5th or 7th (but not the 4th) day of pregnancy. Both treatments were followed by the appearance of W-bodies in the neighbourhood of the blastocysts, the disappearance of the shed zonae, and the appearance of Pontamine Blue reactivity, oedema of the uterine stroma and formation of the primary decidual zone, in that order.
INFLUENCE OF THE ANTERIOR PITUITARY ON THE ALDOSTERONE SECRETORY RESPONSE TO DIETARY SODIUM RESTRICTION IN THE RAT
Authors: LEE T. C. , van der WAL B. , de WIED D. 
Published: December 2008

SUMMARY
Studies of the rate of aldosterone production in vitro of adrenals of rats hypophysectomized before dietary sodium restriction showed that hypophysectomy not only prevented the increases in aldosterone production observed in intact, Na-deprived rats, but also depressed the level of aldosterone production to below that of intact rats maintained on a normal diet. Rats hypophysectomized for a similar period of time but maintained on the normal diet showed a similar decrease.
Experiments on adeno- and neuro-hypophysectomized rats indicated that the pituitary factor required for the normal mineralocorticoid response to dietary sodium restriction resides in the anterior pituitary.
Treatment of hypophysectomized rats during dietary sodium restriction with doses of a long-acting corticotrophin (ACTH) prevented adrenal atrophy and maintained a normal glucocorticoid response to intravenous injections of ACTH, but failed to increase aldosterone production rates in vitro to levels above that of intact rats on a normal diet; it also failed to restore the enhanced adrenocortical sensitivity to the stimulating effect of aldosterone production of intravenously injected ACTH which is characteristic of acutely hypophysectomized, Na-deficient rats. Treatment with anterior pituitary powder (8–12 mg./day) for similar periods, however, restored the aldosterone production of adrenals in vitro of hypophysectomized, Na-deprived rats to levels nearly indistinguishable from those of acutely hypophysectomized, Na-deprived controls. The same doses of anterior pituitary powder were shown not to have any demonstrable effect on the aldosterone production of adrenals in vitro of intact rats on a normal diet.
These results are interpreted as indicating the existence of a pituitary factor other than ACTH which stimulates aldosterone secretion. This factor does not appear to act directly on the adrenal cortex or to stimulate the secretion of specific glomerulotropic substances, but probably exerts its effect by maintaining the normal functional capacity of some as yet undefined tissues which secrete glomerulotropic substances in response to dietary sodium restriction.
STEROID BIOSYNTHESIS IN VITRO BY THE COMPONENT TISSUES OF THE OVARY OF DOGFISH (SCYLIORHINUS CANICULUS L.)
Authors: SIMPSON T. H. , WRIGHT R. S. , HUNT S. V. 
Published: December 2008

SUMMARY
Ovaries of dogfish were separated into their component tissues and incubated separately with [4-14C]dehydroepiandrosterone and androstenedione. Production of Δ4-3-oxosteroids from the former was localized in the follicular membrane, in the post-ovulatory corpora lutea and in the egg yolk. Reduction of androstenedione to testosterone was higher in corpora lutea than in corpora atretica and higher in follicular membranes and yolks taken from ripe follicles than in those taken from atretic eggs. Production of oestradiol-17β from androstenedione was limited to the follicular membranes of ripe follicles and to the ovarian stroma; oestrone production was demonstrated, additionally, in corpora atretica and their membranes. There was no indication of oestriol formation.
THE INFLUENCE OF PLASMA MAGNESIUM CONCENTRATION ON PARATHYROID HORMONE SECRETION
Authors: BUCKLE R. M. , CARE A. D. , COOPER C. W. , GITELMAN H. J. 
Published: December 2008

SUMMARY
The influence of plasma magnesium concentration on parathyroid gland function has been evaluated by perfusion at a constant rate of an isolated parathyroid gland in five goats and one sheep with whole blood of varying magnesium content. The concentration of magnesium in fresh whole blood was adjusted either by dialysis or by the addition of magnesium chloride before the perfusion. In each experiment, the concentration of calcium was maintained constant or was slightly altered to oppose the possible influence of magnesium on the rate of release of parathyroid hormone. Parathyroid hormone concentration in parathyroid venous plasma was estimated by a specific radioimmunoassay.
In each experimental animal we observed that the concentration of parathyroid hormone in the effluent plasma diminished when the concentration of magnesium was raised or increased when the concentration of magnesium was lowered. These observations demonstrate a specific influence of magnesium on the rate of release of parathyroid hormone.
ULTRAMICROCHEMICAL STUDIES ON THE SITE OF FORMATION OF DEHYDROEPIANDROSTERONE SULPHATE IN THE ADRENAL CORTEX OF THE GUINEA-PIG
Authors: JONES T. , GRIFFITHS K. 
Published: December 2008

SUMMARY
Although dehydroepiandrosterone sulphate has been recognized as one of the major secretory products of the human adrenal gland neither its biosynthetic pathway nor its site of formation within the cortex have been extensively studied. Ultramicrochemical techniques, which relate enzymic activity to well-defined groups of cells, have been used in the work now described to study the sulphation of dehydroepiandrosterone in the zones of the guinea-pig adrenal cortex. It has been shown that dehydroepiandrosterone sulphokinase activity resides only in the compact cell of the zona reticularis.