bluuebunny/crossref_metadata_2025_split huggingface dataset:
PREGNANT MARE SERUM GONADOTROPHIN: RATIO OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE ACTIVITIES MEASURED BY RADIORECEPTOR ASSAY
Authors: STEWART FRANCESCA , ALLEN W. R. , MOOR R. M. 
Published: December 2008

SUMMARY
Specific radioreceptor assays for FSH and LH, which employ tissue receptors from rat testis and highly purified human FSH (LER 1575-C) and LH (Hartree IRC-2, 24/6/69) as standards, have been developed to determine the FSH-like and LH-like activities in pregnant mare serum gonadotrophin (PMSG). Measurements of FSH and LH concentrations in the serum of six pregnant Pony mares showed that the ratio of these two activities did not vary significantly between mares and remained constant between days 40 and 80 of gestation with a value of 1·45 ± 0·04 (s.e.m.). The FSH:LH ratio of PMSG produced by cultured equine trophoblast cells was found to be 0·72 ± 0·03 (s.e.m.) and that of partially purified serum extracts of PMSG 1·08 (range 0·87–1·30).
SEXUAL BEHAVIOUR OF NEONATALLY CASTRATED RATS INJECTED DURING INFANCY WITH OESTROGEN AND DIHYDROTESTOSTERONE
Authors: BOOTH JANET E. 
Published: December 2008

SUMMARY
Male rats were castrated on the day of birth (day 1) and injected with either testosterone, dihydrotestosterone, a synthetic oestrogen (RU 2858), RU 2858 + dihydrotestosterone, or oil from days 1 to 5. The aromatizable androgen, testosterone, and RU 2858 suppressed both cyclic gonadotrophin secretion, indicated by the absence of corpora lutea from implanted ovarian grafts, and the behavioural response to oestradiol benzoate + progesterone injections in adulthood. The 5α-reduced androgen, dihydrotestosterone alone did not affect gonadotrophin secretion or female receptive behaviour, but like testosterone, it increased penis development in response to testosterone propionate, and this was positively correlated with copulatory efficiency, i.e. the ratio of intromission to mount frequencies. Nevertheless, ejaculation only occurred among animals that had received testosterone or RU 2858 + dihydrotestosterone. The results support the concept that during the perinatal period, neural conversion of androgens to oestrogens is important both for the suppression of female gonadotrophin secretion and behaviour patterns as well as for the organization of male behaviour patterns. The 5α-reduction of unsaturated C19-steroids to dihydrotestosterone in peripheral tissues is also required to complete the development of the male genital tract.
STRUCTURE–ACTIVITY RELATIONSHIPS OF CORTICOSTEROID FEEDBACK AT THE HYPOTHALAMIC LEVEL
Authors: JONES M. T. , HILLHOUSE E. W. , BURDEN J. L. 
Published: December 2008

SUMMARY
Structure–activity studies on the corticosteroid fast and delayed feedback receptor mechanisms controlling the secretion of corticotrophin releasing factor (CRF) were carried out with the rat hypothalamus in vitro. The secretion of CRF was induced by acetylcholine (3 pg/ml).
The fast feedback receptor appears highly specific, and the structure essential for efficacy involves an 11β-hydroxyl group and an unblocked 21-hydroxyl group. Several steroids showed antagonism and so the binding site is not very specific. 18-Hydroxy,11-deoxycorticosterone, progesterone, 17α-hydroxyprogesterone and 11-deoxycorticosterone were antagonists of fast feedback.
The delayed feedback receptor required either an 11β- or a 21-hydroxyl group for efficacy. The binding site required a 17-hydroxyl group when the 11β- or 21-hydroxyl groups were absent. Binding also involved the 3-oxo,4,5-ene structure since steroids in which these are absent were inactive.
CONTROL OF THE PREOVULATORY SURGE OF LUTEINIZING HORMONE IN THE HEN (GALLUS DOMESTICUS): THE ROLE OF PROGESTERONE AND ANDROGENS
Authors: WILLIAMS J. B. , SHARP P. J. 
Published: December 2008

Peripheral blood samples were taken from laying hens at frequent intervals during various periods of the ovulatory cycle in order to detect small changes in the concentrations of progesterone and androgen which might be important in initiating the preovulatory release of LH.
Blood samples were taken from seven hens at 1 h intervals for 3 h when the ovary contained a mature (C1) follicle and on another occasion, when the largest ovarian follicle was immature. The concentrations of progesterone and androgens in the plasma were 30% higher when there was a mature C1 follicle present in the ovary than when there was not, but this increase was significant (P < 0·05) only for progesterone.
The concentrations of progesterone and androgens were also measured in blood samples taken at 30 min intervals during the 3 h before and after the initiation of the first preovulatory LH surge of a sequence. The hens were kept on a lighting schedule of 14 h light/day and the first LH surge of a sequence was initiated at the beginning of the dark period. Just after the onset of darkness there was a small increase in the concentration of LH in the plasma and a subsequent, larger preovulatory release of LH. The first increase in the level of LH was associated with a small rise in the concentrations of androgens and progesterone in the plasma while the preovulatory release of LH was accompanied by a much larger increase in the secretion of these steroids.
It is proposed that the increase in the level of LH in the plasma at the onset of darkness stimulates the maturing ovarian follicles to secrete progesterone and androgens and that the quantities of these steroids secreted (particularly of progesterone) depends on the maturity of the largest ovarian follicle. If the largest ovarian follicle is mature, then the increase in the level of LH in the plasma associated with the onset of darkness stimulates the secretion of a quantity of progesterone sufficient to cause the preovulatory surge of LH. A diurnal increase in the concentration of LH in the plasma could, therefore, be responsible for timing the preovulatory surges of LH so that they are only initiated at night.
STRESS-INDUCED DECREASES IN THE SERUM CONCENTRATION OF PROGESTERONE IN THE PREGNANT BABOON
Authors: ALBRECHT E. D. , NIGHTINGALE M. S. , TOWNSLEY J. D. 
Published: December 2008

Pregnancy Research Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20014, U.S.A.
(Received 4 January 1978)
During preliminary studies on the rate of production of progesterone in pregnant baboons, an apparent decline was noted in the serum concentration of progesterone during ketamine sedation. Ketamine (Elvidge, Challis, Robinson, Roper & Thorburn, 1976) and phencyclidine (Setchell, Shackleton & Himsworth, 1975) reduce the plasma concentration of cortisol in rhesus monkeys. The present study determined the effect of no sedation, sedation with ketamine or phencyclidine and tranquillization with chlordiazepoxide on the serum concentrations of progesterone and cortisol during serial bleeding of pregnant baboons.
Nine pregnant baboons (Papiopapio) were mated and maintained as described previously (Townsley, 1974) and studied between days 60 and 172 of gestation (term = 184 days). Between 11.00 and 13.00 h baboons were restrained in a squeeze cage and bled (4 ml) via a 21-gauge needle from the saphenous vein; the
ACTIVE IMMUNIZATION OF EWES AGAINST LUTEINIZING HORMONE RELEASING HORMONE, AND ITS EFFECTS ON OVULATION AND GONADOTROPHIN, PROLACTIN AND OVARIAN STEROID SECRETION
Authors: CLARKE I. J. , FRASER H. M. , McNEILLY A. S. 
Published: December 2008

Three Scottish Blackface ewes were immunized against luteinizing hormone releasing hormone (LH-RH) conjugated to bovine serum albumin (BSA) and three control ewes were immunized against BSA alone. When the antibody titre to LH-RH became raised the treated animals failed to show oestrus or ovulate; they had significantly lower levels of plasma luteinizing hormone (LH) and higher levels of prolactin than the controls, whereas the levels of follicle-stimulating hormone (FSH) were unaltered.
The integrity of the hypothalamus-pituitary-gonadal system of these animals was then challenged by the injection of a highly active analogue of LH-RH and by ovariectomy. An i.v. injection of 5 μg d-serine-t-butyl6 des-glycine-NH210 LH-RH ethylamide raised plasma LH and FSH. Ovariectomy caused an eight- and ninefold rise in plasma levels of LH and FSH respectively in controls, but failed to increase plasma levels of LH and FSH in the LH-RH-immunized ewes. Plasma prolactin concentrations in the LH-RH-immunized ewes were significantly reduced by ovariectomy.
RATE OF TESTICULAR MATURATION, IN RELATION TO GONADOTROPHIN AND TESTOSTERONE LEVELS, IN QUAIL EXPOSED TO VARIOUS ARTIFICIAL PHOTOPERIODS AND TO NATURAL DAYLENGTHS
Authors: FOLLETT B. K. , MAUNG S. L. 
Published: December 2008

SUMMARY
Rates of testicular growth and plasma levels of FSH, LH and testosterone were determined in Japanese quail exposed to various fixed photoperiods (number of hours of light: number of hours of darkness): 12L: 12D, 13L: 11D, 14L: 10D, 16L: 8D and 20L: 4D and to natural daylengths. All five artificial photoperiods stimulated spermatogenesis, with the testes reaching maturity after 30–40 days. Maximum rates of testicular growth occurred with 14L: 10D, 16L: 8D or 20L: 4D but the rate was reduced by 50% in birds exposed to 12L: 12D. This reduction was due to decreased growth in the seminiferous tubule epithelium (and hence in tubule diameter); the duration of spermatogenesis hardly being affected. Near maximum growth rates occurred with 13L: 11D.
The hormone profiles offer an explanation for the differential rates of testicular growth. In the three longest photoperiods, FSH rose from 20 ng/ml to peak levels of 300–400 ng/ml after 10 days. As the testes matured, so the level of FSH decreased to 50–100 ng/ml. This pattern was not seen under 12L: 12D; the level of FSH rose slowly to about 100 ng/ml and showed no peak of secretion. With 13L: 11D a small peak was found, which decreased at maturity. In quail with testes > 1500 mg, the level of FSH was invariably about 100 ng/ml. Patterns of LH secretion were rather similar with all treatments, but testosterone was affected by photoperiod; lower levels were found under 12L: 12D than 20L: 4D. The rate of photoperiodically induced testicular growth was proportional to the levels of FSH, and possibly also testosterone, in the circulation.
Outdoors, testicular growth began when daylengths reached about 12 h. Maturity occurred within the next 40 days. The levels of FSH rose steadily but did not show a peak of secretion. In general, the highest levels of hormone were found in July just before gonadal regression which occurred when the daylengths were still quite long.
PARTIAL ALLEVIATION OF THE ANTITESTICULAR EFFECT OF PIPECOLINOMETHYLHYDROXYINDANE BY ZINC IN RATS
Authors: FANG V. S. , FURUHASHI N. 
Published: December 2008

Department of Medicine, The University of Chicago, Chicago, Illinois 60637, U.S.A.
(Received 31 May 1978)
Zinc deficiency in childhood may result in retardation of growth and hypogonadism, since affected adolescent boys show increased growth and sexual maturation after zinc replacement therapy (Sandstead, Prasad, Schulert, Farid, Miale, Bassilly & Darby, 1967; Halsted, Ronaghy, Abadi, Haghshenass, Amirhakemi, Barakat & Reinhold, 1972). Testicular dysfunction has been found after zinc deficiency due to chronic haemodialysis for uraemia and can be reversed by zinc supplements (Antoniou, Shalhoub, Sudhakar & Smith, 1977). Furthermore, oligospermic men, after treatment with zinc, showed increased plasma concentrations of androgens and raised sperm counts (Hartoma, Nahoul & Netter, 1977). The present study investigated the preventative effects of zinc on rats treated with dl-6-(N-α-pipecolinomethyl)-5-hydroxyindane maleate (PMHI), a potent and specific antitesticular agent whose mechanism of action has yet to be determined (Boris, DeMartino & Trmal, 1974).
Three groups of 28-day-old male Sprague–Dawley
SYNTHESIS OF PROLACTIN BY HUMAN DECIDUA IN VITRO
Authors: GOLANDER AVRAHAM , HURLEY THOMAS , BARRETT JANET , HANDWERGER STUART 
Published: December 2008

SUMMARY
To determine whether human decidua and/or chorion synthesizes and secretes prolactin, explants of decidua obtained at Caesarian section and explants of chorion from the membranes separating dizygotic twins were cultured for periods of up to 6 days. The decidual explants released 366 ± 37 ng prolactin/100 mg tissue (mean ± s.d.) during each day in culture and incorporated 3H-labelled amino acids into immunoprecipitable prolactin. In the radioimmunoassay for prolactin, serial dilutions of incubation medium displaced 125I-labelled prolactin parallel to the displacement by pituitary prolactin and the prolactin in the medium eluted from Sephadex G-150 in a position identical to that of pituitary prolactin. Chorionic explants released prolactin into the incubation medium during day 1 of culture only and did not incorporate 3H-labelled amino acids into prolactin. These results demonstrate that prolactin is synthesized by the decidua and not by the chorion and suggest that the decidua is the source of prolactin in amniotic fluid.
ALTERATIONS IN LEVELS OF THYROTROPHIN RELEASING HORMONE AND RATES OF HORMONE DEGRADATION IN HYPOTHALAMIC TISSUE OF THE DEVELOPING RAT
Authors: PEASE KATHLEEN , SHEN HIRAM , ACRES G. S. , RUPNOW J. H. , DIXON J. E. 
Published: December 2008

SUMMARY
Developmental changes in levels of hypothalamic thyrotrophin releasing hormone (TRH) and the role that hypothalamic degrading enzymes may play in these alterations were investigated. Levels of TRH in male and female fetal rats and in male neonatal rats were measured by radioimmunoassay. The hormone content of the hypothalamus was shown to increase from less than 1 ng at 1–4 days of age to approximately 10 ng at 20 days of age. Thereafter, the content of TRH declined to the adult level of about 5 ng. The ability of fractionated hypothalamic homogenates to degrade TRH was measured over the same time. The 27 000 g supernatant fraction contained a degrading activity that yielded only radiolabelled deamido-TRH upon incubation with [l-proline 2,3-3H]TRH. The corresponding particulate fraction contained at least two distinct TRH degrading activities as determined by the number of metabolites present. Changes in rates of degradation were not large enough to account for the differences observed in levels of TRH.
CONTROL OF GONADOTROPHIN SECRETION IN THE FEMALE TAMMAR WALLABY (MACROPUS EUGENII)
Authors: EVANS SUSAN M. , TYNDALE-BISCOE C. H. , SUTHERLAND R. L. 
Published: December 2008

A heterologous radioimmunoassay for tammar wallaby FSH, using an ovine FSH antiserum and a human FSH tracer, is described. With this assay concentrations of FSH in plasma of intact female tammars are not detectable except rarely at the time of oestrus. However the assay has proved useful in studies of the control of gonadotrophin secretion in intact male and in ovariectomized tammars.
In the female tammar, concentrations of LH and FSH in plasma rose within a few days of bilateral ovariectomy. Ovariectomized tammars respond to a luteinizing hormone releasing hormone stimulus (10 μg, i.v.) with a prompt release of LH, peak levels of 16·9 ± 1·4 ng NIH-LH-S19/ml plasma (n = 12) being reached within 25 min of injection. Concentrations of LH and FSH in plasma were reduced to preoperative values in ovariectomized tammars when lutein tissue developed in ovarian cortex grafts autotransplanted under the pouch skin. Ovarian interstitial tissue was not necessary for this effect.
After lutectomy during quiescence, the female tammar ovulates again in about 14 days. Injections of progesterone (700 μg/kg per day, i.m.) for 7 days after the operation did not delay this response, but follicular development and ovulation appeared to be retarded in animals given oestradiol-17β (5 μg/kg per day, i.m.) with or without progesterone.
EFFECTS OF SYNTHETIC MAMMALIAN GONADOTROPHIN RELEASING HORMONE AND DOGFISH HYPOTHALAMIC EXTRACTS ON LEVELS OF ANDROGENS AND OESTRADIOL IN THE CIRCULATION OF THE DOGFISH (SCYLIORHINUS CANICULA L.)
Authors: JENKINS N. , DODD J. M. 
Published: December 2008

Intravenous injection of synthetic mammalian gonadotrophin releasing hormone (GnRH; 5 μg per fish) induced a significant increase in androgen levels in the circulation of male dogfish within 4 h. Female dogfish injected with 10 μg GnRH in November showed significantly raised plasma levels of androgens and oestradiol-17β after 90 min as well as an increase in the rate of oviposition. Twice this dose of GnRH failed to produce significant increases in plasma levels of oestradiol in female dogfish in February and the androgen response in these animals was less than that seen after injection of GnRH in November.
Injection of an acid extract of dogfish hypothalamus significantly increased plasma levels of androgen and oestradiol in female fish when they were compared with control fish injected with extracts of dogfish cerebellum and the latency of response was similar to that encountered when GnRH was injected. It was concluded that the dogfish hypothalamus contains a factor capable of increasing plasma sex steroid levels in the same species and which is similar in its effects to mammalian GnRH.
PLACENTAL TRANSFER OF ALDOSTERONE IN THE SHEEP
Authors: WINTOUR E. M. , COGHLAN J. P. , HARDY K. J. , LINGWOOD B. E. , RAYNER M. , SCOGGINS B. A. 
Published: December 2008

To determine the percentage of the maternal secretion of aldosterone which crosses the placenta the blood clearance rate (BCR) of aldosterone was measured in pregnant sheep and in chronically cannulated fetuses by the constant infusion of [3H]aldosterone alternately into the maternal and fetal compartments. When equilibrium had been reached the concentration of [3H]aldosterone was measured in both maternal and fetal compartments. Aldosterone BCR in eight pregnant ewes was 98 ± 5 (s.e.m.) litres/h which was not significantly different from that of ten non-pregnant ewes at 95 ± 5 litres/h. The BCR of aldosterone in seven fetuses was 24 ± 2 litres/h. A small percentage (4·4 ± 0·3; n = 7) of the maternal production rate was transferred to the fetus, whilst 29 ± 4% (n = 8) of the fetal production rate was transferred to the maternal compartment.
When aldosterone was measured in maternal and fetal blood samples collected simultaneously from sodium-replete sheep more than 80% of the aldosterone in fetal blood was of fetal origin if the actual fetal concentration of aldosterone was greater than 1·5 ng/dl.
EVIDENCE THAT CHANGES IN LUTEINIZING HORMONE SECRETION REGULATE THE GROWTH OF THE PREOVULATORY FOLLICLE IN THE EWE
Authors: McNATTY K. P. , GIBB MARION , DOBSON CAROLYN , THURLEY D. C. 
Published: December 2008

The aim of the present study was to gain evidence that the level of LH secretion preceding the preovulatory LH surge is an important determinant of follicular maturation and corpus luteum function in the ewe. In addition it was hoped to establish whether the pattern of LH delivery to the ovary (pulsatile v. constant) is a critical factor in the maturation of a preovulatory follicle.
To accomplish this, progesterone-primed anoestrous ewes were repeatedly injected i.v. with LH or luteinizing hormone-releasing hormone (LH-RH), or given an i.v. infusion of LH, over a 72 h period. These animals, together with the appropriate controls, were exposed to a sexually active ram so that oestrous activity could be recorded. All ewes were subjected to intensive blood sampling regimes so that the plasma levels of LH and progesterone could be determined and compared to those which occurred in the same breed of sheep during the oestrous cycle.
Collectively the data suggest that the plasma levels of LH preceding the preovulatory LH surge are an important determinant of follicular maturation as judged by subsequent corpus luteum function. Moreover, they show that follicular maturation can be achieved with widely differing patterns of LH delivery to the ovary during the preovulatory period and that a strict pulsatile delivery of LH may not be an absolute requirement.
THYROID-STIMULATING ANTIBODIES IN GRAVES'S DISEASE AND THE EFFECT OF THYROTROPHIN-BINDING GLOBULINS ON THEIR DETERMINATION
Authors: BÍRÓ J. 
Published: December 2008

Globulin preparations from the sera of 104 untreated patients with Graves's disease have been tested for their thyroid-stimulating antibody (TSAb) activities. Eighty-one of the samples (78%) were positive in the assay for the thyrotrophin-binding inhibitory immunoglobulins, 48 samples (46%) contained human thyroid adenyl cyclase stimulators (HTACS) and 71 (68%) contained human thyroid stimulators (HTS) measured as stimulation of colloid droplet formation in human thyroid slices. All 104 samples were positive in one or other of the assays, 29 (28%) were positive in all three assays and 38 (37%) in two.
All samples were tested for their specific TSH-binding characteristics, 40 (38%) possessed 'B-type' binding sites (previously characterized as TSH-binding sites with low affinity but high capacity for the ligand) but the remaining 64 samples (62%) were no different from normal control samples and had 'A-type' binding sites (high affinity but low capacity binding sites for TSH). Samples without detectable thyrotrophin-binding inhibitory immunoglobulin did not contain B-type TSH-binding globulins. Globulins exhibiting B-type binding were more active in the HTACS and HTS assays.
The B-type TSH-binding globulins have a characteristic, dose-dependent reducing effect on the human thyroid adenyl cyclase stimulation by TSH whereas A-type globulins do not. Globulins exhibiting B-type TSH-binding may therefore have a significant effect on assays for TSAb activities. The methods used to measure TSAb have been reviewed from this point of view.
HOURLY FLUCTUATIONS IN THE BLOOD LEVELS OF MELATONIN, PROLACTIN, LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, TESTOSTERONE, TRI-IODOTHYRONINE, THYROXINE AND CORTISOL IN RAMS UNDER ARTIFICIAL PHOTOPERIODS, AND THE EFFECTS OF CRANIAL SYMPATHECTOMY
Authors: LINCOLN G. A. , ALMEIDA O. F. X. , KLANDORF H. , CUNNINGHAM R. A. 
Published: December 2008

Eight adult Soay rams (four control and four cranially sympathectomized by removal of the superior cervical ganglia) were exposed to alternating 16-week periods of short days of 8 h light: 16 h darkness (8L : 16D) and long days (16L : 8D) for more than 3 years, and the changes in the diameter of the testes were recorded. Once during short days and once during long days blood samples were collected hourly for 28 h, and the concentrations of melatonin, prolactin, FSH, LH, testosterone, tri-iodothyronine (T3), thyroxine (T4) and cortisol were measured by radioimmunoassay.
In the control rams the testes were reduced in size during long days compared to short days, and the blood concentrations (24-h mean values) of FSH, LH and testosterone were decreased. The levels of prolactin were much increased, while there was no significant change in the mean levels of melatonin, T3, T4 and cortisol. During both photoperiods there was considerable hour-to-hour variation in all eight hormones indicative of episodic secretion, as well as a consistent variation related to the time of day which was most pronounced for melatonin and T3. There was a clear difference in the daily profile of plasma melatonin levels between short and long days.
In the superior cervical ganglionectomized rams there were no significant changes in the size of the testes or in the hormone titres between short and long days. Compared to the controls the plasma levels of LH, FSH, testosterone and prolactin were in the intermediate range. Some consistent diurnal variation was evident in the levels of all the hormones measured, with a pattern similar to the controls for a few of the hormones (e.g. T3) but quite different for others (e.g. melatonin).