bluuebunny/crossref_metadata_2025_split huggingface dataset:
STEROIDS IN THE OVARIAN VENOUS BLOOD OF EWES BEFORE AND AFTER GONADOTROPHIC STIMULATION
Authors: SHORT R. V. , McDONALD M. F. , ROWSON L. E. A. 
Published: December 2008

SUMMARY
Ewes on the 9th and 15th days of the oestrous cycle were injected intravenously with follicle stimulating hormone, luteinizing hormone and prolactin of sheep pituitary origin, human chorionic gonadotrophin, pregnant mares' serum and an endometrial extract. The ovarian vein was cannulated, and progesterone measured chemically in the venous effluent. None of the above substances was capable of producing a pronounced or sustained alteration in the rate of progesterone secretion in the hour following injection. It was concluded that the ovine corpus luteum, if it responds at all to gonadotrophic stimulation, must do so in a manner very different from the testis, the response of which to luteinizing hormone is both immediate and sustained.
The mean secretion rate of progesterone was approx. 150 μg./hr., thus being of the same order of magnitude as a previous indirect estimate of 113 μg./hr. There was no difference in the secretion rate between the 9th and 15th days of the cycle, apart from one animal at the 15th day in which the corpus luteum had ceased to secrete progesterone altogether.
The turnover time of progesterone in the corpus luteum was 10 min., suggesting that the hormone is released from the gland as soon as it is formed.
Pooled samples of ovarian vein plasma collected during the mid- and late luteal stages of the cycle contained, apart from progesterone, pregnenolone, 20α-hydroxypregn-4-en-3-one, oestrone and oestradiol-17β.
In three samples of ovarian vein plasma collected from ewes in oestrus it was impossible to detect progesterone or 20α-hydroxypregn-4-en-3-one, even after chorionic gonadotrophin therapy. Oestradiol-17β and oestrone were present in concentrations similar to those found during the luteal phase of the cycle. Since the rate of ovarian vein blood flow is lower at oestrus than during the luteal phase, it follows that the oestrogen secretion rates are also lower at oestrus.
The 24 hr. secretion rate of oestradiol-17β in two oestrous ewes was 3·3–7·4 μg. This is in close agreement with the median effective dose of 7 μg. of oestradiol-17β needed to induce oestrus in the spayed, progesterone-primed ewe.
OBSERVATIONS ON A DITHIOCARBAMOYLHYDRAZINE AS AN INHIBITOR OF PITUITARY GONADOTROPHIC ACTIVITY
Authors: BROWN P. S. 
Published: December 2008

SUMMARY
A dithiocarbamoylhydrazine (ICI 33828) was injected s.c. into intact rats and mice. It usually caused a reduction in weight of the uterus or of the accessory organs in the male, but less commonly of the gonads. As little as 0·5 mg. daily for 4 days caused significant effects in adult female rats, while half this dose on alternate days retarded maturation in male rats.
ICI 33828 was injected with exogenous gonadotrophin in three systems of assay and in some cases it modified the response to the gonadotrophin. This may not be due to a specific effect at the gonadal level but either to suppression of endogenous gonadotrophins in the test animals or to the effect of ICI 33828 on their general condition.
Pituitary glands from male rats treated with ICI 33828 were assayed for follicle stimulating hormone (FSH) and found to contain significantly less than glands from control rats. This suggests that ICI 33828 acts by reducing the formation of pituitary gonadotrophin.
SEX HORMONES IN FISH. PART II. THE OESTROGENS OF SCYLIORHINUS CANICULUS
Authors: SIMPSON T. H. , WRIGHT R. S. , HUNT S. V. 
Published: December 2008

SUMMARY
Whole ovaries of the lesser spotted dogfish (Scyliorhinus caniculus) have been shown to contain oestradiol-17β and oestrone, each in a concentration of ca. 19 μg./kg., corresponding to approximately 0·8 μg./fish. The greater part (approximately 80%) of this material is localized within the eggs, the remainder being found in the ovarian tissue. The concentrations of oestradiol and oestrone in the eggs appear to be constant, independent of the size of egg, thus the amounts of these compounds in the egg increase as the egg matures. Free oestradiol-17β and oestrone have been found in blood plasma in respective concentrations of between 3 and 4 μg./l. and 0·5–1 μg./l.; protein-bound oestrone and oestradiol also appeared to be present, though in quantities too small for adequate characterization. No conjugated oestrogens could be detected. There is a significant difference between the ratios of oestradiol to oestrone in the eggs, ovarian tissue and blood plasma.
STUDIES ON THE TERMINATION OF PREGNANCY WITH NORETHYNODREL
Authors: DAVIS B. K. 
Published: December 2008

SUMMARY
An intraperitoneal injection of 0·3 mg. norethynodrel on day 2 post coitum significantly diminished the rate of nidation among ovariectomized mice supplemented with progesterone and oestradiol. Presence of the ovary partly mitigated this action. The factor of greatest quantitative significance involved in impeding nidation was found to be that responsible for decreasing the recovery of blastocysts from the uterus. Evidence implicating tubal locking was sought, but not obtained. Degenerated blastocysts were recovered from the uterus, but only infrequently. Results of studies involving transplantation of blastocysts to ovariectomized pseudopregnant hosts revealed that the rate of nidation among recovered blastocysts was only slightly affected in one of two experiments by treatment of the donor with norethynodrel. However, a dose of 0·6 mg. norethynodrel given to the host 2 days after induction of pseudopregnancy elicited a response that almost completely inhibited nidation. Norethynodrel was found to counteract the deciduomagenic action of progesterone on the rat uterus.
The steroid caused extensive foetal resorption in intact and ovariectomized mice when given intraperitoneally in a dose of 2 mg./day from days 8–10 p.c.
THE EFFECT OF AMINE OXIDASE INHIBITORS ON PREGNANCY
Authors: POULSON EVELYN , ROBSON J. M. 
Published: December 2008

SUMMARY
The effects of seven amine oxidase inhibitors on pregnancy were investigated in mice. Four of the compounds were derivatives of hydrazine and three were not. All the derivatives of hydrazine and one of the other compounds tested produced toxic effects in early pregnancy but were relatively inactive later.
The effect of one of the compounds investigated (HP 1325) was, to a great extent, reversed by either progesterone or prolactin, suggesting an interference with the hormonal mechanism responsible for the maintenance of pregnancy.
HP 1325 (and 5-hydroxytryptamine) did not interrupt pseudopregnancy, indicating that luteal function is not completely inhibited.
Evidence is adduced that the effects on pregnancy are not related to any particular chemical structure or to the amine-oxidase activity of the compound tested.
STUDIES ON ARTIFICIAL CRYPTORCHIDISM: DEGENERATIVE AND REGENERATIVE CHANGES IN THE GERMINAL EPITHELIUM OF THE RAT TESTIS
Authors: CLEGG E. J. 
Published: December 2008

SUMMARY
1. In the rat bilateral artificial cryptorchidism results in degenerative changes in the seminiferous tubules which are maximal about the 15th day after operation. Up to this stage all germ cells are reduced in number, spermatogonia being least affected and spermatids most. Spermatogonial mitoses and spermatocytial meioses are also inhibited to some extent.
2. Following this initial phase of degeneration there is a partial regeneration, most marked in the case of spermatocytes and total germ cells, which at the 35th day results in the formation of early spermatids.
3. The degree of germ-cell degeneration after 15 days of cryptorchidism is greater than the maximal degeneration after hypophysectomy. It is considered that the increased environmental temperature of the testes may 'block' the action of gonadotrophins on the seminiferous tubules as well as damage the germ cells directly. The occurrence of a certain degree of regeneration may indicate that this 'block' can be overcome to some extent by increased production of pituitary gonadotrophins.
DETECTION AND ASSAY OF PROLACTIN BY THE LOCAL LACTOGENIC RESPONSE IN THE RABBIT
Authors: CHADWICK A. 
Published: December 2008

SUMMARY
The assay of prolactin by the technique of mammary-intraductal injection in pseudopregnant rabbits was investigated both by subjective assessment of the lactogenic response and by estimation of the lactose synthesized locally in the glands.
Factors affecting the response were studied. The threshold levels of prolactin needed to induce lactation in the rabbit were determined. Of the breeds investigated, New Zealand White rabbits were the most sensitive to lactogenic stimuli. However, no breed gave uniform results and the main obstacle to the routine application of the assay method is the inherent variability of the rabbits. Nevertheless, the assay does provide a useful semi-quantitative method for assessing the effects of prolactin.
THE RENAL ACTION OF SMALL DOSES OF CORTISOL AT NIGHT
Authors: IMRIE M. J. , MILLS J. N. , WILLIAMSON K. S. 
Published: December 2008

SUMMARY
Cortisol, 15 mg., injected intravenously in nine human subjects at 23.00 hr. increased K+ in urine excreted between midnight and 02.00 hr. but effects on Na+ excretion were variable. No significant changes in creatinine excretion were observed.
In further experiments on one subject cortisol was infused intravenously at 4 or 6 mg./hr. from 21.00 to 02.00 hr. Little regular difference from controls was seen in excretion of either sodium or potassium.
The results are discussed in the light of the suggestion that secretion of cortisol in the morning raises excretion of sodium and potassium from the low night value.
GRANULOSA CELL TUMOUR OF THE OVARY IN A VIRGIN HEIFER
Authors: SHORT R. V. , SHORTER D. R. , LINZELL J. L. 
Published: December 2008

SUMMARY
A case is described of a granulosa cell tumour of the ovary in a virgin heifer, which was showing signs of nymphomania.
The cyst fluid from the tumour contained progesterone, 20β-hydroxypregn-4-en-3-one, possibly a trace of 17α-hydroxyprogesterone, and oestradiol-17β. The progesterone: oestradiol-17β ratio was only 6:1, and yet the tumour appeared to have caused normal mammary development and lactation.
A STUDY OF THE HORMONAL REQUIREMENTS FOR OVUM IMPLANTATION IN THE RAT, BY MEANS OF DELAYED NIDATION-INDUCING SUBSTANCES (CHLORPROMAZINE, TRIFLUOPERAZINE)
Authors: PSYCHOYOS A. 
Published: December 2008

SUMMARY
A new phenothiazine derivative trifluoperazine ('Stelazine') appears to be more effective than chlorpromazine in causing delayed nidation in the rat.
Treatment, started on day 3 of normal pregnancy and repeated every 24 hr., induced delayed nidation in over 80% of the animals treated. This delay was corrected, and implantation brought about, immediately after the exogenous supply of 0·1 μg. of oestradiol.
In a second series of experiments, a single injection of Stelazine was given to females, subsequently spayed and treated with progesterone, and was found to postpone the stage from which ovariectomy is compatible with ovum implantation.
The results obtained support the hypothesis that nidation is induced, under normal conditions, by a release of oestrogen on day 4 of pregnancy. It is suggested that tranquillizers influence ovum implantation by postponing, through the pituitary cycle, this discharge of oestrogen.
CHANGES IN THE MAMMARY GLANDS OF RATS AND MICE DURING PREGNANCY, LACTATION AND INVOLUTION
Authors: MUNFORD R. E. 
Published: December 2008

SUMMARY
The changes in five measurements and four derived estimates of histological structure of the mammary gland were followed in rats and mice killed at 3-day intervals throughout pregnancy and lactation, or pregnancy, lactation and involution, respectively. A polynomial regression equation was fitted to the data for each variable.
In the rat and to a lesser degree in the mouse, there was a striking fall in the number of alveoli per unit area at the time of parturition and a corresponding rise in alveolar diameter. The number of nuclei in the average alveolar cross-section was relatively constant during the latter part of pregnancy and in lactation, but increased approximately twofold about the time of parturition. There was little change in the estimate of total alveoli after parturition whereas volume of glandular tissue (estimated by the product of proportion of glandular tissue and area of histological section) increased steadily from early pregnancy to a maximum value in the middle or latter part of lactation. The curve fitted to the estimate of total nuclei was almost a perfect parabola in the mouse, with a maximum value at about day 7 of lactation, but was more nearly linear in the rat.
CHANGES IN THE MAMMARY GLANDS OF RATS AND MICE DURING PREGNANCY, LACTATION AND INVOLUTION
Authors: MUNFORD R. E. 
Published: December 2008

SUMMARY
The changes in the level of deoxyribonucleic acid (DNA) and in the activities of alkaline and acid phosphatases were followed in the mammary glands of rats and mice killed at intervals of 3 days during pregnancy and lactation or pregnancy, lactation and involution, respectively. Polynomial regression equations were fitted to the data after they had been transformed to a logarithmic scale. During pregnancy and lactation, the general form of the curves described by the equations were similar for DNA and alkaline phosphatase, however expressed, and for acid phosphatase, other than when expressed as a concentration per mg. of DNA. All equations had a large linear term with a smaller significant negative and/or cubic term. During most of pregnancy and in early lactation the curves showed a steep, almost linear rise. During early pregnancy the slope was somewhat lower, while in the latter part of lactation the rate of increase was small or became negative. In the mouse, when the values for animals killed during involution were included in the analyses, the equations tended to be dominated by the quadratic term, a reflexion of the steep fall in the levels of all constituents after weaning.
If the assumption was accepted that the average DNA content of cells did not change during the lactational cycle, the following conclusions could be drawn. In the rat, the marked similarity of the equation for total content of DNA and for concentration of DNA (per unit weight of tissue corrected for 'milk' content) indicated that the increase, and subsequent decrease, in cell numbers was mirrored almost exactly by inverse changes in average cell mass. The equations describing changes in total content of DNA (expressed in logarithms) implied that, for both species, the mitotic rate in the mammary gland was constant, or nearly constant, for most of pregnancy and the first part of lactation. In the rat and in the mouse, the increase in total alkaline phosphatase activity during pregnancy and throughout most of lactation was in part due to an increase in the enzyme activity per cell. On the other hand, the changes in total activity of acid phosphatase seemed to be due entirely to changes in the number of cells.
CALCIUM EXCRETION IN THERMAL SWEAT IN THYROTOXICOSIS
Authors: HARDEN R. McG. 
Published: December 2008

SUMMARY
The calcium excretion and concentration in thermal sweat was found to be significantly higher in thyrotoxic patients than in controls or treated thyrotoxic patients.
In the thyrotoxic patients there was a correlation between the excretion of calcium in the sweat and the urinary excretion of calcium.
Significant amounts of calcium may be lost in the sweat in thyrotoxicosis and losses by this route must be taken into account in calcium balance studies.
THE DISTRIBUTION AND TURNOVER OF CORTISOL IN SHEEP
Authors: PATERSON J. Y. F. 
Published: December 2008

SUMMARY
When labelled cortisol was injected intravenously into sheep it disappeared rapidly from blood. A few minutes after injection the specific activity of plasma cortisol decreased in a simple exponential manner, and it was therefore assumed that cortisol was contained in one pool. Cortisol pool sizes and turnover rates were calculated from plasma cortisol specific activity and its rate of change. The estimates of turnover rates so calculated are higher than the rates of cortisol secretion reported by other workers. Because the turnover of cortisol in sheep is rapid it is possible that the assumption that cortisol is contained in one pool might give erroneously high values for the cortisol turnover rate.
THE EFFECT OF THYROID HORMONES ON WATER PERMEABILITY OF THE ISOLATED BLADDER OF THE TOAD BUFO BUFO
Authors: GREEN K. , MATTY A. J. 
Published: December 2008

SUMMARY
Thyroxine at 10−6m concentration enhances water movement from the mucosal to the serosal surface of the isolated toad bladder in the absence of an osmotic gradient. It is suggested that this is caused by the effect of thyroxine on sodium transport which creates a driving force for the increased water movement. Thyroxine caused this effect when applied on either side of the membrane, but was more effective when applied to the serosal surface.
Incubation of different bladders successively in the same triiodothyronine solution indicated that triiodothyronine may be rapidly utilized.
A mixture of thyroxine and triiodothyronine caused a diphasic effect on water loss down an osmotic gradient.
The analogues tetraiodothyroproprionic acid and tetraiodothyroformic acid had no effect on water movement down an osmotic gradient across the isolated toad bladder nor did they affect oxygen uptake or sodium transport.
The results support the concept that thyroxine and triiodothyronine act on permeability processes in and across cell membranes.
COMPLETE RESTORATION OF LACTATION IN THE GOAT AFTER HYPOPHYSECTOMY
Authors: COWIE A. T. , KNAGGS G. S. , TINDAL J. S. 
Published: December 2008

SUMMARY
Studies have been carried out on the restoration and maintenance of lactation in six goats hypophysectomized during lactation. Three of these received replacement therapy some time after the operation when the milk yields had fallen to a very low level, and the other three received replacement therapy immediately after the operation. It was found that the combination of ovine prolactin (300 i.u. twice daily), bovine somatotrophin (12·5 mg./day or 6·25 mg. twice daily), triiodo-l-thyronine (0·5 mg./day), zinc protamine insulin (8 i.u./day) and tablet implants of dexamethasone could restore the milk yield to the pre-operative level when therapy was started some time after hypophysectomy. The same combination of hormones maintained milk secretion at the pre-operative level when therapy was started immediately after operation.
COMPARATIVE ASPECTS OF CORTISOL TRANSPORT: LACK OF FIRM BINDING TO PLASMA PROTEINS IN DOMESTIC RUMINANTS
Authors: LINDNER H. R. 
Published: December 2008

SUMMARY
The concentration of cortisol in peripheral plasma (μg./100 ml.) was 0·6 ± 0·1 (s.e.) in penned sheep accustomed to handling and 1·1 ± 0·2 in untrained grazing sheep, or about 1/10 of the basal level in man or the guinea-pig. Plasma cortisol in the goat (mean 1·2) and the ox (2·6 ± 0·3) was also low.
Freely diffusible cortisol was distinguished from protein-bound hormone by gel filtration after equilibration of the plasma with 3H- or 14C-labelled steroid. The binding capacity (μg./100 ml.) of sheep plasma for cortisol at room temp. (1·7 ± 0·2) was only slightly above that of 5% ovine albumin solutions. It compared with 3·5 (2·2–4·6) in the goat, 6·1 ± 1·0 in the ox, 14–21 in the guinea-pig, 17–23 in normal human and 25–59 in human pregnancy plasma. These are minimal estimates, since partial dissociation of the transcortin-cortisol complex occurred under the test conditions. Sheep plasma showed no significant elevation in cortisol concentration or binding power during pregnancy, nor in response to oestrogen administration.
At physiological cortisol levels and room temperature, 39 ± 5% of the cortisol in sheep plasma was protein bound, but values above 40% were associated with low plasma cortisol levels and hence confined to samples from trained or adrenalectomized sheep. ACTH administration or addition of very small amounts of cortisol to ovine plasma in vitro caused a sharp fall in this percentage. Moreover, at body temperature only 9 ± 2% of the plasma cortisol in the sheep was non-diffusible. This finding may account for the great sensitivity of target tissues to the changes of blood cortisol level in this species. In human pregnancy plasma 86–95% of plasma cortisol (> 14μg./100 ml.) was bound at room temperature and 60–74% at 37°.
Published data and those now presented suggest that plasma level and biological half-life of cortisol in different animal species are directly related to binding capacity.
A NEW BIOASSAY METHOD FOR LUTEINIZING HORMONE DEPENDING ON THE DEPLETION OF RAT OVARIAN CHOLESTEROL
Authors: BELL E. T. , MUKERJI S. , LORAINE J. A. 
Published: December 2008

SUMMARY
A new assay method for luteinizing hormone (LH) activity is described and the criteria for its reliability are assessed. The technique depends on ovarian cholesterol depletion in intact immature rats pretreated with pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG).
The main advantage of the ovarian cholesterol depletion (OCD) test is its high sensitivity, the assay being approximately five million times more sensitive than the ovarian ascorbic acid depletion (OAAD) method. The chief disadvantage of the technique is its relatively low degree of precision.
The LH activity of various gonadotrophin preparations has been determined by the new OCD test. The results obtained agree well with those found by the OAAD method.
The extreme sensitivity of the OCD test suggests that it will be eminently suitable for clinical use.
AUDIOGENIC SEIZURES IN ADULT FEMALE OVARIECTOMIZED RATS (SPRAGUE-DAWLEY) TREATED WITH SEX HORMONES
Authors: WERBOFF J. , HEDLUND L. , HAVLENA JOAN 
Published: December 2008

SUMMARY
Adult female albino rats of the Sprague-Dawley strain were ovariectomized or sham-operated and tested for their susceptibility to audiogenic seizures at regular intervals after operation. The animals were given daily injections of hormones (testosterone, progesterone, or oestradiol) at different dose levels. A total of 372 animals, divided into twenty-six groups according to initial seizure susceptibility and treatment, were used. The results showed that, in the seizure-resistant animals, ovariectomy did not significantly alter the incidence of audiogenic seizures. Testosterone and progesterone produced a significant increase in seizure susceptibility in the sham-operated group only. Oestradiol significantly increased seizure incidence in both operated groups. In the seizure-susceptible animals (ovariectomized and sham-operated) all hormones produced significant decreases in seizure incidence. Of the three hormones, testosterone produced the most marked decrease in seizures, followed by progesterone and, finally, oestradiol.
THE METABOLISM OF TESTOSTERONE BY TISSUE FROM NORMAL AND NEOPLASTIC RAT BREAST
Authors: KING R. J. B. , GORDON J. , HELFENSTEIN JANET E. 
Published: December 2008

SUMMARY
The qualitative and quantitative metabolism of testosterone by rat mammary gland and hydrocarbon-induced mammary tumours has been investigated. These tissues contain a Δ4-5α-hydrogenase, 3-ketosteroid reductase and 17 β-hydroxysteroid dehydrogenase. The qualitative picture was the same in all the tissues studied but a quantitative difference was evident. In general, the tumours metabolized more steroid than mammary gland tissue taken from animals in late pregnancy. No conversion of testosterone to oestrone or oestradiol could be detected.