bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECTS OF HYPOPHYSECTOMY AND THE PARADOXICAL EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON THE VIABILITY OF HAMSTER SPERMATOZOA
Authors: LUBICZ-NAQROCKI C. M. , GLOVER T. D. 
Published: December 2008

SUMMARY
Spermatozoa in the ligatured cauda epididymidis of golden hamsters were tested for their fertilizing ability 12 days after hypophysectomy or after hypophysectomy and treatment with testosterone or human chorionic gonadotrophin (HCG). Fertility trials showed that the mean fertilization rate was reduced to approximately 65% of the control level, which contrasts sharply with the previously reported effects of castration, which led to the infertility of spermatozoa within 12 days as a result of androgen withdrawal.
The present study showed that loss of fertilizing ability in hypophysectomized animals was also due to a decrease in circulating androgens since treatment with testosterone or HCG (10 or 40 i.u./day) prevented the adverse effect of hypophysectomy. However, there was some indication that sperm survival might also be directly or indirectly dependent, in part, on hypophysial hormones. While daily doses of HCG (10 or 40 i.u./day) maintained fertilizing ability in hypophysectomized animals, treatment with intermediate doses (especially 20 i.u./day) reduced the mean fertilization rate to 40·8%. This paradoxical effect of HCG on sperm survival was shown not to be mediated by the adrenal glands: the magnitude of the effect was related to the amount of testicular tissue present. Thus, when only one testis was present the adverse effect of 20 i.u. HCG/day was reduced by approximately half whereas the spermatozoa retained a high fertilizing ability in animals that were both castrated and hypophysectomized and treated with testosterone. It is suggested that the biphasic effect of HCG is due to the peripheral conversion of limited but significant amounts of circulating testicular androgens into oestrogens which antagonize the effect of testosterone in the epididymis. Attention is drawn to the possibility that specific dose levels of HCG might also be detrimental to sperm survival in the treatment with gonadotrophins of infertility in men.
KINETIC STUDIES WITH 125I-LABELLED FOLLICLE-STIMULATING HORMONE
Authors: BUTT W. R. , RYLE MARGARET , SHIRLEY ANNE 
Published: December 2008

SUMMARY
Follicle-stimulating hormone (FSH) labelled with 125I which retained its biological activity was injected into immature mice. Accumulation in, and loss from, the ovaries and some other tissues were studied. The ovarian content was maximal 40 min after injection. By 30 min the specific radioactivity of the ovary was proportional to that of the blood. Previous injection of a large dose of unlabelled FSH reduced accumulation of 125I-labelled FSH by one-third only. Subsequent injection of a large dose of unlabelled FSH accelerated loss of 125I-labelled FSH. It was concluded (i) that the 125I-labelled FSH behaved like normal FSH; (ii) that the immature mouse ovary has numerous binding sites; (iii) that the attachment of FSH to the binding sites is labile; (iv) that the concentration in the ovary tends to equilibrate with that in the blood. Similar conclusions were drawn from parallel studies using cultured infantile mouse ovaries. These also suggested that depletion of 125I-labelled FSH from the ovary involved a second-order reaction.
THE SPECIFICITY OF AN OVINE PITUITARY INCUBATION SYSTEM LINKED WITH GONADOTROPHIN ASSAYS FOR DETECTING GONADOTROPHIN RELEASING ACTIVITY
Authors: HARTLEY BARBARA M. , CRIGHTON D. B. , LAMMING G. E. 
Published: December 2008

SUMMARY
A sheep pituitary incubation system was developed which may be used to study the release of both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as assayed biologically. Specificity was examined by adding at high concentration various materials present in the hypothalamus, a crude acid extract of sheep cerebral cortex or crude or partly purified extracts of ovine hypothalamic tissue.
Of the materials tested for LH and FSH releasing activity, oxytocin, adrenaline, synthetic lysine vasopressin and cerebral cortex extract failed to influence LH or FSH release. Natural vasopressin containing unknown proportions of the lysine and arginine forms did not affect FSH release but produced a significant increase in the LH content of the medium, the reason for which was not clear. Noradrenaline failed to influence FSH release but produced an apparent depression in the LH content of the medium due to an action on the LH released or upon the ovarian ascorbic acid depletion assay since the addition of noradrenaline to standard ovine LH reduced the potency in the assay to an almost identical degree.
Extracts of ovine hypothalamic tissue consistently increased the LH and FSH content of the medium.
The method described may be applicable to the detection and estimation of LH and FSH releasing activity in ovine hypothalamic tissue extracts and to detecting changes in the responsiveness to hypothalamic stimulation of sheep pituitary tissue.
EFFECTS OF EXTENDED LACTATION AND 9α-FLUOROPREDNISOLONE ACETATE ON SERUM THYROXINE AND LACTATIONAL PERFORMANCE
Authors: LORSCHEIDER F. L. , MEARS G. J. 
Published: December 2008

SUMMARY
The effects of extending lactation up to 48 days on serum thyroxine (T4), and its relationship to lactational performance, were studied with rats fed a ration containing 1·0 μg I−/g of feed. The effects of chronic administration of 9α-fluoroprednisolone acetate on serum T4 during prolonged lactation were also determined. Lactation was prolonged by substitution of foster litters at 8-day intervals. Serum T4 was measured by a competitive protein-binding assay.
Chronic administration of 9α-fluoroprednisolone acetate up to 32 days resulted in a significant increase in serum thyroxine in non-lactating rats. In saline-treated rats lactating up to 48 days, serum T4 was initially reduced by 30% at 16 days, but progressively increased as lactational performance (expressed as gain in weight of pups) decreased. This inverse correlation was attributed to a progressive decline in mammary gland competition for iodine and to a progressive depletion of corticosterone which may have exerted an antithyroid effect initially. Rats treated with 9α-fluoroprednisolone acetate and lactating up to 48 days, had serum T4 levels which were lower than values for corresponding saline-treated lactating rats, but were similar to those levels observed in saline-treated non-lactating rats. This may indicate a higher rate of thyroid hormone utilization in lactating rats treated with 9α-fluoroprednisolone acetate and may also explain the ability of these rats to maintain a better lactational performance than saline-treated lactating rats. Comparisons of each 8-day extended lactation period showed that in all cases lactational performance was greater for mothers treated with 9α-fluoroprednisolone acetate; up to 113% more from 16 to 24 days lactation, up to 153% more from 24 to 32 days lactation, 146% more from 32 to 40 days lactation, and 317% more from 40 to 48 days lactation, despite the fact that by day 48 maternal body weight of lactating rats treated with 9α-fluoroprednisolone acetate was not different from that of saline-treated lactating rats. A hypothesis proposed for the hormonal maintenance of lactation suggests that the maintenance of euthyroid levels of serum T4 due to treatment with 9α-fluoroprednisolone acetate is necessary for the continued prolactin-induced mammary synthesis of fatty acids and nucleic acids. Both glucocorticoids and thyroxine may be rate limiting to milk synthesis.
CYTOCHROME P-450 ACTIVITY IN SHEEP CORPORA LUTEA DURING THE OESTROUS CYCLE
Authors: SIMPSON E. R. , JEFCOATE C. R. , COLLETT R. A. , LAND R. B. 
Published: December 2008

SUMMARY
Cytochrome P-450 of mitochondria from the ovine corpus luteum was examined on different days throughout the oestrous cycle. Most, if not all, of the mitochondrial cytochrome P-450 appeared to be of the type involved in cholesterol side-chain cleavage, as determined by steroid binding spectra. The content of mitochondrial cytochrome P-450 in the corpus luteum changed considerably throughout the cycle, and closely paralleled the rise and fall of plasma progesterone concentration; the correlation between these two parameters was 0·96. This was largely a reflection of the changes in weight of the corpus luteum throughout the cycle, since the specific content of cytochrome P-450 changed much less dramatically. The percentage of the mitochondrial cytochrome P-450 present as the cholesterol—substrate complex remained constant throughout the cycle at about 25–30% of the total.
STUDIES ON THE BINDING ACTIVITY FOR THE LONG-ACTING THYROID STIMULATOR
Authors: DIRMIKIS SUSAN , MUNRO D. S. 
Published: December 2008

SUMMARY
The binding activity of fresh human thyroid homogenates for the long-acting thyroid stimulator (LATS) was shown to be principally associated with the particulate fraction. LATS binding activity (LAA) could be partially released into the soluble fraction by freezing and thawing of thyroid homogenates. By delaying freezing and thawing until the particulate fraction had been washed repeatedly it was possible to obtain highly purified preparations of LAA.
EFFECT OF GONADOTROPHINS ON THE PRODUCTION OF STEROIDS BY SHEEP OVARIAN FOLLICLES CULTURED IN VITRO
Authors: MOOR R. M. , HAY MARY F. , McINTOSH J. E. A. , CALDWELL B. V. 
Published: December 2008

SUMMARY
The main objective of the study was to determine the rate at which Graafian follicles of sheep that had been treated with exogenous gonadotrophin acquire the ability to secrete oestrogen in vitro. Follicles were explanted from sheep 5 min to 24 h after injection of pregnant mare serum gonadotrophin (PMSG) and kept individually in culture for 7 days. The mean daily output of oestrogen by follicles from PMSG-treated sheep was higher than that secreted by follicles from untreated sheep. However, only a certain proportion of the follicles from each sheep secreted significant amounts of oestrogen in vitro; these follicles were called 'stimulated'. The proportion of stimulated follicles was 5% for control sheep, 20–30% for follicles explanted from sheep 5 min to 12 h after injection with PMSG, and 80% for follicles explanted from sheep that had been injected with PMSG 24 h previously.
In the second part of the study, the pattern of oestrogen and progesterone secretion by stimulated follicles of different sizes explanted from PMSG-treated sheep at various stages of the oestrous cycle was determined. Up to the 14th day, oestrogen production in vitro by follicles over 4·5 mm in diameter reached a maximum 2 days after PMSG injection and decreased thereafter; progesterone production rose steadily as the oestrogen levels declined. In contrast, follicles of less than 4·5 mm diameter secreted considerable amounts of oestrogen for the first 5 days in culture, but produced only small quantities of progesterone. In follicles explanted on day 15, oestrogen secretion decreased steadily from the beginning of the culture period and was very low by the 4th day. Most follicles explanted at oestrus secreted only small amounts of oestrogen in vitro but secreted large amounts of progesterone.
THE EFFECTS OF OXYTOCIN AND VASOPRESSIN DURING THE OESTROUS CYCLE AND PREGNANCY ON THE UTERUS OF A MARSUPIAL SPECIES, THE QUOKKA (SETONIX BRACHYURUS)
Authors: HELLER H. 
Published: December 2008

SUMMARY
Uteri of the marsupial species Setonix brachyurus suspended in a solution with a cation concentration similar to that of Setonix plasma ultrafiltrate, responded to oxytocin, arginine-vasopressin (AVP) and arginine-vasotocin at all stages of the oestrous cycle (28 days) and gestation (27 days). In cyclic intact non-pregnant animals the potency of AVP in evoking contractile responses of the uterus was greater than that of oxytocin when the myometrium was oestrogen-dominated, i.e. from about day 19 to about 2 days after oestrus. In contrast, during the luteal phase (day 7–18) the uterine muscle was much more responsive to oxytocin than to AVP, although the threshold concentration for oxytocin was raised. The uteri of bilaterally ovariectomized quokkas responded more markedly to AVP than to oxytocin after treatment of the animal in vivo with an oestrogen. The responsiveness of uteri of progesterone-treated ovariectomized quokkas to vasopressin was equal to or less than their responsiveness to oxytocin.
The response of the pregnant Setonix uterus to oxytocin was always greater than that to AVP, even late in pregnancy when at the corresponding stage of the oestrous cycle in the non-pregnant quokka (day 19–23) the myometrium was more responsive to AVP than to oxytocin. At earlier stages of pregnancy there were indications of a similar degree of progesterone block to oxytocin as during the luteal phase in non-pregnant Setonix.
It has frequently been assumed that the endocrine milieu in marsupials is the same during the oestrous cycle and in pregnancy. The present results suggest that there are differences.
A SIMPLIFIED METHOD FOR MEASURING THYROIDAL UPTAKE OF TECHNETIUM99m USING DIRECTIONAL COUNTING
Authors: GRAY H. W. , HOOPER L. A. , GREIG W. R. 
Published: December 2008

SUMMARY
The uptake of technetium-99m (99mTc) by the thyroid was measured 15 min after injection using a directional counting technique. The 'washout' of thyroidal 99mTc after intravenous perchlorate injection was quantitated so that separate measurement of the extrathyroidal activity of 99mTc was unnecessary.
In normal subjects the thyroidal uptake was 1·28 ± 0·61% of the administered dose (mean ± 1 s.d.); in primary myxoedema 0·26 ± 0·28%, in simple goitre 2·18 ± 2·10%, in thyrotoxicosis 11·0 ± 5·4%, in hypothyroid patients with Hashimoto's disease 4·50 ± 3·70% and in three patients with Pendred's syndrome the mean uptake was 9·3%.
The technique has been evaluated and its advantages as a simple alternative to quantitative scintiscanning are discussed.
STEROID METABOLISM BY AN OESTROGEN-DEPENDENT INTERSTITIAL-CELL TUMOUR OF A RAT TESTIS
Authors: JULL J. W. , McCLELLAN D. , COUPEY S. 
Published: December 2008

SUMMARY
Steroid metabolism by a unique, transplantable, oestrogen-induced, hormone-dependent interstitial-cell tumour of a rat testis was investigated. After incubation of the minced tumour in medium without substrate the presence of 3α-androstanediol, 3-epiandrosterone and androsterone was shown. There was inconclusive evidence for the presence of smaller amounts of 3β-androstanediol, and no evidence for testosterone. [14C]Pregnenolone substrate was shown to be metabolized after 2 h to androstenedione, androsterone and a small amount of testosterone. Epi- and dehydroepiandrosterone were probably formed from [14C]pregnenolone, but were incompletely characterized.
THE BIOLOGICAL HALF-LIVES OF RIBOSOMAL AND TRANSFER RNA IN THE MOUSE UTERUS
Authors: MILLER B. G. 
Published: December 2008

SUMMARY
Estimates were obtained of the half-lives of ribosomal RNA (rRNA) and transfer RNA (tRNA) in the uteri of ovariectomized mice receiving daily doses of 6 or 25 ng oestradiol, or no oestrogen injections. Apparent half-lives were calculated from data for the loss of radioactivity from rRNA and tRNA fractions after a single intravenous injection of [methyl-3H]l-methionine. The half-life of rRNA in mice which received no oestradiol injections was about 7 days and decreased to about 4 days in mice that received either 6 or 25 ng oestradiol daily. The half-life of tRNA after all treatments was about 3 days.
MITOGENIC ACTION OF OESTRADIOL-17β ON HUMAN MYOMETRIAL AND ENDOMETRIAL CELLS IN LONG-TERM TISSUE CULTURES
Authors: CHEN LOUISE , LINDNER H. R. , LANCET M. 
Published: December 2008

SUMMARY
Dispersed human endometrial and myometrial cells grown for up to 4 months as monolayer cultures responded to addition of oestradiol-17β (1 × 10−9 mol/l) to the medium by increased [3H]thymidine incorporation into DNA, and an increased rate of cell division. Cultures derived from uterine leiomyomata showed a less consistent mitotic response to the hormone.
Normal endometrial and myometrial cells grown in the oestradiolenriched medium showed a significantly higher efficacy of colony formation (increases of about 60 and 90%, respectively) than cells grown in control medium throughout the experimental period. Exposure to the hormone for 3–4 days was sufficient to induce this effect, which suggests that it does not depend on selection of hormone-sensitive cells. The mitogenic effect of oestradiol, as expressed by increased cloning efficacy, persisted for several days after transfer of the cells to a hormone-free medium. Cultures of foetal rat skeletal muscle failed to respond to oestradiol-17β in the cloning test, and oestradiol-17α was without effect on uterine cells.
It is concluded that oestradiol-17β exerts a direct mitogenic action on some cellular components of the human endometrium and myometrium in vitro.
A STUDY OF THE ANDROGEN RECEPTORS IN A VARIETY OF ANDROGEN-SENSITIVE TISSUES
Authors: MAINWARING W. I. P. , MANGAN F. R. 
Published: December 2008

SUMMARY
A search has been conducted for specific, 5α-dihydrotestosterone-binding proteins in a wide variety of tissues and cells upon which androgenic steroids have pronounced morphological and biochemical effects. High affinity binding proteins of this nature have been identified in cytoplasmic and nuclear extracts from a diversity of accessory sexual glands of many species, mouse kidney, testis and certain experimental androgen-dependent tumours. They are notably absent in most types of skeletal muscle and in soluble extracts prepared from prokaryotic organisms. The implications of these findings to the mechanism of action of androgenic steroids are discussed. While the selective binding of 5α-dihydrotestosterone indubitably plays a role of paramount importance in the mechanism of action of androgens in many accessory sexual glands throughout life, this process may be of importance in other tissues only during the period of early growth and development. A severe limitation to the importance of the binding of 5α-dihydrotestosterone in certain adult tissues is imposed by the very low activity of the enzyme, 5α-reductase, responsible for the formation of 5α-dihydrotestosterone.
IMMUNORADIOMETRIC AND TWO-SITE ASSAY OF HUMAN FOLLICLE-STIMULATING HORMONE
Authors: READHEAD CAROL , ADDISON G. M. , HALES C. N. , LEHMANN H. 
Published: December 2008

SUMMARY
An immunoradiometric assay for human follicle-stimulating hormone (FSH) is described. A non-specific antiserum to human FSH was purified by incubation of the antiserum with human luteinizing hormone and thyroid-stimulating hormone before its reaction with an immunoadsorbent containing human FSH. The specific antibodies to human FSH isolated on immunoadsorbent were iodinated and used for the FSH assay. The sensitivity of the assay was improved by the extraction of plasma FSH onto antibody-coated polyethylene tubes before its reaction with iodinated FSH antibodies producing a two-site assay. Optimal conditions for the preparation and use of antibody-coated tubes in such a procedure are described. Using serial extraction a sensitivity of 11 pg/ml (0·1 mu./ml) was achieved. There was good agreement between the results obtained with this method and those obtained with radioimmunoassay. The advantages of the increased sensitivity of this new method are discussed.
PITUITARY AND PLASMA GONADOTROPHIN LEVELS AND SPERMATOGENESIS IN THE GOLDFISH CARASSIUS AURATUS AFTER METHALLIBURE TREATMENT
Authors: BRETON B. , JALABERT B. , BILLARD R. 
Published: December 2008

SUMMARY
The level of gonadotrophin measured by radioimmunoassay in fully mature male goldfish was about 15 ng carp gonadotrophic hormone (c-HG)/ml plasma and 30 μg c-HG/g pituitary (wet weight). After treatment for 35 days with methallibure (added to the water at the rate of 2 p.p.m./day), the level of gonadotrophin in the blood was very low and remained at the pretreatment level in the pituitary. This suggested that releasing factor might control either synthesis or discharge of gonadotrophin from the pituitary. These results have also shown that type B spermatogonia and meiosis were gonadotrophin dependent but that the development of spermatocytes into spermatids did not require high concentrations of gonadotrophin. Spermiation was suppressed when the concentration of c-HG dropped below 10 ng/ml plasma.
SEX DIFFERENCES AND HORMONAL CONTROL OF TESTOSTERONE METABOLISM IN RAT PITUITARY AND BRAIN
Authors: DENEF CARL , MAGNUS CAREW , McEWEN B. S. 
Published: December 2008

SUMMARY
The in-vitro conversion of testosterone to 17β-hydroxy-5α-androstan-3-one (5α-dihydrotestosterone, DHT) and 3α, 17β-dihydroxy-5α-androstane (3α-androstanediol, DIOL) in pituitary and slices of brain regions was compared between male and female rats. Intact pituitaries from male rats formed 2·5 times more DHT and 1·5 times more DIOL than those of females. A small sex difference was also detected in the hypothalamus, males again being higher than females. No sex differences could be detected in other brain regions. However, DHT formation in the brain was regionally differentiated with higher conversion rates in hypothalamus than in cortex, hippocampus, amygdala, pineal gland or cerebellum. The highest transformation, however, was found in the mid-brain. Metabolism in the pre-optic area was as low as that in the cortex.
5α-Dihydrotestosterone and DIOL formation in the pituitary increased several-fold after gonadectomy in both sexes and the sex difference disappeared. Little or no increase occurred after thyroidectomy or adrenalectomy. The increase in pituitary DHT formation after gonadectomy could be attenuated or prevented both by treatment with testosterone propionate and with oestradiol benzoate. Replacement therapy, particularly with oestradiol benzoate, gave rise to a sex difference reminiscent of that of normal animals. No significant change in pituitary DHT formation occurred in adult females which had been treated with testosterone propionate on the 4th day of life.
The results suggested a close relationship between DHT formation and activity of gonadotrophin secretion, particularly at the level of the pituitary.
THE EFFECT OF d-ALDOSTERONE AND SPIRONOLACTONE ON THE CONCENTRATION OF SODIUM AND POTASSIUM IN THE MILK OF RATS
Authors: YAGIL R. , ETZION Z. , BERLYNE G. M. 
Published: December 2008

SUMMARY
The effects of d-aldosterone and spironolactone on the sodium and potassium concentrations in the milk of rats were determined. d-Aldosterone caused a highly significant fall in the milk sodium concentration and the Na:K ratio when compared with control animals. The administration of spironolactone shortly before aldosterone gave results not significantly different from control animals. It is concluded that aldosterone has a specific sodium-lowering action in the milk of the lactating rat.
STEROID METABOLISM IN VITRO BY AN INTERSTITIAL CELL TUMOUR AND THE ATTACHED PREPUBERTAL TESTIS
Authors: RICHARDS GWEN , NEVILLE A. MUNRO 
Published: December 2008

SUMMARY
A virilizing interstitial cell tumour and the attached testicular tissue from a 4-year-old boy were incubated in vitro with [7α-3H]pregnenolone and [4-14C]progesterone, or [4-14C]androstenedione and [7α-3H]5α-dihydrotestosterone. Ring A saturated steroids were produced from 4-ene precursors by the prepubertal testis, but this tissue was unable to convert pregnenolone or progesterone to 17α-hydroxylated C21 steroids, or to C19 steroids.
The virilizing interstitial cell tumour metabolized pregnenolone and progesterone to 17α-hydroxyprogesterone, androstenedione and testosterone. In addition, dehydroepiandrosterone was detected as a product of pregnenolone. The tumour lacked 4-ene-5α-steroid reductase activity.
5α-Dihydrotestosterone was metabolized to 5α-androstane-3,17-dione, androsterone, isoandrosterone, 5a-androstane-3α,17β-diol and 5α-androstane-3β,17β-diol in both the normal and tumour tissue.
The significance of these metabolic pathways is discussed.