Amount Of Follicle-stimulating Hormone Research Articles

Protective Role of Rosa damascena Miller hydroalcoholic extract on Oxidative Stress Parameters and Testis Tissue in Rats Treated with Sodium Arsenite

Regarding the strong antioxidant properties of Rosa damascene extract, this study aimed to investigate the protective role of Rosa damascene Miller hydroalcoholic petal extract on oxidative stress parameters and testis tissue in rats treated with sodium arsenite. To this end, 30 male rats were divided into five groups, including control, positive control (treated with arsenite), and three groups of patients affected by sodium arsenite with 150 mg/kg, 300 mg/kg, and 450 mg/kg Rosa damascene extract for 34 days by gavage. The animals were then anesthetized, and the blood samples were collected from the heart. The left testis was removed for histopathological studies. The findings revealed that Sodium arsenite in the positive group caused a significant reduction in TAC, testosterone, and serum Luteinizing hormone (LH) and a significant increase in serum Malondialdehyde. In addition, there was no statistically significant difference among the groups regarding the amount of Follicle-stimulating hormone (FSH). Moreover, the consumption of Rosa damascene extract with sodium arsenite caused a significant increase in testosterone, LH, and FSH compared to the positive control group. Histopathological results showed that in the experimental group receiving a dosage of 300 mg/kg b.w and the control group, the number of sperm tubes increased, and the germinal epithelium’s thickness was appropriate. Daily treatment with Rosa damascene extract with a dosage of 300 mg/kg b.w for 34 days could improve the changes caused by sodium arsenite and reduce Malondialdehyde levels. Thus, it seems that Rosa damascene hydroalcoholic extract can effectively improve the male reproductive system’s function.

Effect of FSH and eCG on Alpaca (Vicugna pacos) Oocyte Maturation in vitro

This study evaluated alpaca oocytes that developed to metaphase II (MII), using different concentrations of follicle stimulating hormone (FSH) with and without equine chorionic gonadotropin (eCG) during in vitro maturation. Oocytes were obtained from ovaries of slaughtered alpacas. Oocytes were matured in vitro for 36h in TCM-99 and supplemented in groups with different doses of FSH: 0.5, 0.25, 0μg.mL-1 and eCG: 15, 5, 0IU.mL-1. Oocytes were stained with 2% lacmoid, and examined for their nuclear status. The parameter for comparisons between groups was the percentage of oocytes in MII. There was an interaction between FSH and eCG (P<0.05). A higher percentage of oocytes in MII were obtained when using 0.5µg.mL-1 of FSH with any concentration of 15, 5 or 0IU.mL-1 of eCG [58.4±1.94% (n=78); 59.5±1.94% (n=85); 54.3±0.56% (n=81); P<0.05]. A similar percentage was also found using 0.25µg.mL-1 of FSH plus 15IU.mL-1 of eCG [52.3±1.66% (n=86); P>0.05] followed by 0.25µg.mL-1 of FSH with 5 or 0IU.mL-1 of eCG [47.3±1.94% (n=82); 45.3±1.94% (n=86); P<0.05]. The lowest maturation percentages were found using any concentration of eCG without FSH [8.2±0.73% (n=84); 8.0±0.66% (n=74); 11.4±1.23% (n=71); P<0.05]. In conclusion, the addition of eCG to the maturation medium would reduce the amount of FSH required in the in vitro maturation of alpaca oocytes.

Effects of methyl-beta-cyclodextrin on the release of luteiniz-ing hormone, follicle stimulating hormone, prolactin and growth hormone from cultured bovine anterior pituitary cells

The aims of the present study are to clarify the effect of methyl-beta-cyclo-dextrin (MβCD) on the secretions of luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL) and growth hormone (GH) from the anterior pituitary (AP) cells of prepubertal male cattle and to compare the characteristics of secretion to those of gonadotrophic-releasing hormone (GnRH), thyrotropin- releasing hormone (TRH) and growth hormone-releasing hormone (GHRH), respectively. The AP cells prepared from six castrated Holstein calves (age: 8-11 months) were incubated for 2 h with MβCD (10-3 M, 10-2 M), GnRH (10-8 M), TRH (10-8 M) and GHRH (10-8 M) or vehicle only as a control (CTL). The amount of LH, PRL and GH released in the medium was measured by a time-resolved fluoroimmunoassay (TRFIA). The amount of FSH released in the medium was measured by the radioimmunoassay (RIA). MβCD significantly (P<0.05) stimulated the secretion of LH, FSH, PRL and GH from the AP cells. Furthermore, GnRH significantly (P<0.05) stimulated the secretion of LH and FSH. Also, TRH and GHRH significantly (P<0.05) stimulated the secretion of PRL and GH, respectively. However, the potency of the MβCD was less compared to each respective hormone secretions in response to GnRH, TRH and GHRH (P<0.05).

Association of rs13405728 polymorphism of LHR gene with slow ovarian response

To assess the association of rs13405728 polymorphism of luteinizing hormone receptor (LHR) gene with slow ovarian response during assisted reproductive technology (ART). Two hundred and thirty-six women were enrolled and grouped according to their genotypes. The rs13405728 polymorphism was genotyped by DNA sequencing. No signifiicant difference was found in antral follicle count and anti-Mullerian hormone between the three genotypes (P>0.05). The incidence of slow response in genotype GG was lower than in the other two genotypes (P<0.05). There was no significant difference in the amount of follicle stimulating hormone required, the number of follicles ≥14 mm on human chorionic gonadotrophin day, oocytes, mature oocytes, available embryos, and the clinical pregnancy rate among the three genotypes (P>0.05). There was an independent correlation between slow ovarian response with the genotypes of rs13405728, the initial dose of gonadotropin, and the dose of luteinizing hormone required (P<0.05). Rs13405728 of the LHR gene may be associated with slow ovarian response in ART. Various mechanisms may be involved in the poor response and slow response.

Follicle-stimulating hormone responsiveness in antral follicles from aryl hydrocarbon receptor knockout mice

BackgroundPrevious studies have demonstrated that pre-pubertal aryl hydrocarbon receptor knockout (AHRKO) mice have slow antral follicle growth and reduced capacity to produce estradiol compared to wild-type (WT) mice. Although previous studies have suggested that this is likely due to a reduced ability of the AHRKO follicles to respond to follicle-stimulating hormone (FSH), this possibility was not directly tested. Thus, the goal of these studies was to test the hypothesis that low FSH responsiveness is responsible for the slow growth and reduced estradiol production observed in pre-pubertal AHRKO versus WT antral follicles.MethodsAntral follicles from WT and AHRKO mice were cultured with varying amounts of FSH (0–15 IU/mL) for up to 7 days, and subjected to measurements of growth, FSH receptor and steroidogenic regulator expression, sex steroid hormone levels, and inhibin beta-A expression. General linear models (GLM) for repeated measures were used to compare follicle diameters over time among treatments. If the global tests from GLM were significant, Tukey’s tests were used for pairwise comparisons. Remaining comparisons among groups were performed using one-way analysis of variance followed by Tukey’s post hoc test.ResultsThe results indicate that FSH stimulated growth in both WT and AHRKO follicles, but that high levels of FSH (10–15 IU/mL) were required for AHRKO follicles to reach maximal growth, whereas lower levels of FSH (5 IU/mL) were required for WT follicles to reach maximal growth. Further, FSH stimulated expression of FSH receptor, steroidogenic factors, and inhibin beta-A as well as production of steroid hormones in both WT and AHRKO follicles, but the degree of stimulation differed betw een WT and AHRKO follicles. Interestingly, FSH treatment increased expression of FSH receptor, some steroidogenic regulators, inhibin beta-A, and steroid hormone production more in AHRKO follicles compared to WT follicles.ConclusionsCollectively, these data suggest that the slow growth, but not reduced steroidogenesis in AHRKO follicles, is due to their reduced ability to respond to FSH compared to WT follicles. These data also suggest that the AHR may contribute to the ability of FSH to stimulate proper follicle growth, but it may not contribute to FSH-induced steroidogenesis.

Prediction of ovarian reserve based on day-3 serum follicle stimulating hormone concentrations during the pituitary suppression cycle using a gonadotropin releasing hormone agonist in patients undergoing in vitro fertilization–embryo transfer

Satisfactory results following in vitro fertilization–embryo transfer (IVF-ET) treatments depend on retrieving an appropriate number of mature oocytes without causing the development of ovarian hyperstimulation syndrome (OHSS). The present study was carried out to investigate whether the ovarian reserve is predictable based on the day-3 serum concentration of follicle stimulating hormone (FSH) during the pituitary suppression cycle using a gonadotropin releasing hormone (GnRH) agonist (defined as day-3 FSH) in patients undergoing IVF-ET treatment. Day-3 FSH before the administration of gonadotropin was assessed in 72 IVF-ET cycles from 59 infertile women. The mean ± SD of day-3 FSH, the total amount of FSH plus human menopausal gonadotropin (hMG) administered, and the total number of oocytes retrieved was 5.5 ± 2.6 mIU/ml, 2834.2 ± 1236.5 IU and 7.7 ± 5.8, respectively. There were significant correlations between day-3 FSH and the total amount of FSH–hMG administered (p < 0.001), and day-3 FSH and total number of oocytes retrieved (p < 0.001). There was a significant difference of day-3 FSH between patients who subsequently conceived (4.4 ± 1.3 mIU/ml) and those who did not conceive (6.1 ± 2.9 mIU/ml) (p = 0.001). There was also a significant difference of day-3 FSH between patients who developed moderate or severe OHSS (4.5 ± 1.2 mIU/ml) and those who did not (5.9 ± 2.8 mIU/ml) (p = 0.003). Receiver-operator characteristic curve analysis showed that the significant cut-off point for day-3 FSH for predicting ovarian reserve was 5.25 mIU/ml. These findings indicate that day 3-FSH is useful for predicting ovarian reserve during the pituitary suppression cycle using a GnRH agonist in patients undergoing IVF-ET.

Role of LH and FSH in ovarian function

Human gonadotrophin preparations have been used in the treatment of infertility for almost four decades. The earliest preparations were derived from urine from postmenopausal women and contained approximately equal amounts of follicle stimulating hormone (FSH) and luteinizing hormone (LH) activities. However, with the recognition that FSH is the principal regulator of follicular growth and maturation, these have been largely superseded by highly purified urinary FSH preparations and, more recently, recombinant human FSH (r-hFSH). Because of its complexity, r-hFSH is expressed in mammalian cells grown in culture and, from a manufacturing stand point, offers superior purity and batch-to-batch consistency, compared with urinary preparations. A number of clinical trials have compared the efficacy of r-hFSH and urinary FSH in women undergoing assisted reproductive technologies (ART). In general, these have shown that fewer FSH ampoules are required to achieve ovarian stimulation with r-hFSH, while the number of oocytes retrieved and embryos produced are higher than with urinary FSH. Additionally, the results of a recent meta-analysis have also shown that the clinical pregnancy rate per cycle started is significantly higher with r-hFSH, compared with urinary FSH. Furthermore, in poor responder patients, higher implantation rates were seen in patients treated with r-hFSH than in those treated with urinary FSH, suggesting that embryo viability is increased following use of the recombinant preparations. The finding that FSH preparations produce effective ovarian stimulation compared to human menopausal gonadotrophins in women undergoing ART raises the question of whether LH is required for ovarian stimulation. This has been investigated in a number of recent studies. For example, results have suggested that implantation rates may actually be lower in women who received exogenous LH. Such studies suggest, therefore, that in normogonadotrophic women, the addition of LH to an r-hFSH regimen does not add any further clinical benefit and may actually be detrimental. Hence, it appears that LH administration is necessary only in women with hypogonadotrophic hypogonadism. In conclusion, r-hFSH is a consistently pure and high quality gonadotrophin preparation and contributes to increasing the successful outcome of an ART cycle. Together with careful auditing of routine clinical practice, and the application of evidence-based medicine to facilitate clinical decision making, this means that a total quality management approach can be applied to optimize the outcome of assisted reproduction.

A model of follicular development and ovulation in sheep and cattle.

A dynamic model to describe ovarian follicular development following commitment has been developed. It identifies follicular growth with oestradiol production and assumes that this growth is the result of intra-ovarian stimulation, gonadotrophin stimulation, and inhibitory interactions among the follicles, where larger follicles suppress the growth of the smaller follicles. The variables of the model are the levels of oestradiol in each follicle at commitment, the rate of change of oestradiol production by individual follicles during follicular development, and the level of oestradiol that will induce luteinizing hormone (LH) surge. Changes in the variables of the model could be associated with both genetic and environmental effects. The behaviour of the model is consistent with experimental observations. The model can be expanded to include exogenous follicle-stimulating hormone (FSH) administration assuming that FSH is associated with advancing the maturation of gonadotrophin-dependent follicles without affecting the number of committed follicles. The use of the model to explore FSH administration strategies is demonstrated. The model confirms that the response to FSH administration depends on both the amount of FSH and the time of administration. The largest number of double ovulations occurred when FSH was given at the time of the deviation of the dominant and subordinate follicles.

Correlation between the amount of follicle-stimulating hormone administered and plasma and follicular fluid vascular endothelial growth factor concentrations in women undergoing in vitro fertilization

Vascular endothelial growth factor (VEGF) is a powerful mediator for vessel permeability and it is strongly implicated in angiogenesis, stimulating endothelial cell proliferation as well as capillary permeability. We studied 30 women undergoing in vitro fertilization (IVF) programs and evaluated, on the day of oocyte retrieval, VEGF levels in plasma and follicular fluid and related such concentrations to the amount of follicle-stimulating hormone (FSH) administered. Furthermore, the correlation between the number of oocytes retrieved and the VEGF concentrations both in plasma and in follicular fluid were also investigated.Results indicate that follicular fluid VEGF concentrations and the amount of pure FSH administered were directly proportional (p < 0.05). On the day of oocyte retrieval, the VEGF plasma concentrations and the number of oocytes collected were directly proportional (p < 0.05). VEGF plasma levels increased after human chorionic gonadotropin (hCG) administration (30.37± 18.60 pg/ml up to 52.62 ± 43.63 pg/ml).In conclusion, this study demonstrates that the doses of pure FSH administered to women undergoing IVF cycles have a crucial role in hCG-dependent VEGF production.

Endocrinology: Ultrasonographic appearance of polycystic ovaries is associated with exaggerated ovarian androgen and oestradiol responses to gonadotrophin-releasing hormone agonist in women undergoing assisted reproduction treatment

While no single biochemical test is diagnostic of polycystic ovary syndrome (PCOS), most patients show a characteristic ovarian ultrasonographic appearance. It has been proposed that a dysfunction of cytochrome P-450c17 alpha in PCOS leads to an increased 17-hydroxyprogesterone (17-OHP) response to a gonadotrophin-releasing hormone (GnRH) agonist-induced gonadotrophin rise. We postulated that this abnormality of steroid metabolism might influence the ovarian response during assisted reproduction treatment. We investigated 106 patients undergoing a short 'boost' stimulation regimen for assisted reproduction treatment, including in-vitro fertilization and gamete intra-Fallopian transfers. The ovarian ultrasound pattern was correlated with serum testosterone, 17-OHP, androstenedione and oestradiol responses, and with the clinical outcome. Polycystic ovaries, defined ultrasonographically as the presence of > or = 10 follicles between 2 and 10 mm diameter in either ovary, were found in 48% of the whole study population. Dexamethasone was given to suppress adrenal androgen secretion. Functional ovarian hyperandrogenism (FOH) was defined as serum testosterone > 0.5 nmol/l after dexamethasone. There was a significantly (P < 0.001) higher prevalence of FOH in patients with polycystic ovaries (23%) compared with normal ovaries (7%). Patients with polycystic ovaries had approximately double the 17-OHP, androstenedione and oestradiol responses to a GnRH agonist as patients with non-polycystic ovaries. Exaggerated 17-OHP and oestradiol responses to GnRH agonist were found in 89% of patients with clinically diagnosed PCOS. The number of oocytes retrieved was positively correlated (r = 0.51, P < 0.001) with the oestradiol responses in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of gonadotrophin dose on pre-embryo recovery and development in superovulated mice

A dose-response analysis was performed by stimulating mice with Humegon, which contains approximately equal amounts of follicle stimulating hormone (FSH) and luteinizing hormone (LH). The effect of increasing stimulation was assessed by monitoring the number and developmental stages of pre-embryos flushed from the tubes, and the developmental potency of these pre-embryos after culturing for 72 h. Increasing the stimulation doses resulted in an increased recovery of 2-cell pre-embryos. A maximal plateau of 40-50 2-cell pre-embryos was reached after stimulation with 15-30 IU FSH/LH. Higher stimulation doses up to 50 IU FSH/LH showed no further increase in pre-embryo recovery. Increased stimulation doses did not affect the number of 1-cell pre-embryos or the number of pre-embryos which developed further than the 2-cell stage. An average of 88 +/- 1.7% of the flushed pre-embryos were 2-cell pre-embryos. The fraction of flushed pre-embryos which developed into blastocysts after 72 h of culturing was constant at all stimulation doses, with an average of 81 +/- 1.9%. A maximal plateau of 35-40 blastocysts was reached after stimulating with 15-30 IU FSH/LH. The group of pre-embryos at less advanced developmental stages and the group of degenerated pre-embryos showed a small but dose dependent increase in number. In conclusion, we found that increasing doses of Humegon resulted in an increased recovery of pre-embryos capable of preimplantation development. This increased recovery occurred despite the high level of LH contained in this FSH/LH stimulation.

Refractoriness to follicle-stimulating hormone in rat ovarian granulosa cells—a concentration- and time-dependent phenomenon

Granulosa cells from pre-ovulatory ovarian follicles of rats were exposed, in vitro, to one or two pulses of follicle-stimulating hormone (FSH) in a superfusion apparatus. The superfusate was analysed for cyclic adenosine-3',5' monophosphate (cAMP) and steroids. In experiments with two consecutive FSH pulses, the response to the second pulse (100 ng/ml) was inversely related to the concentration of the first FSH pulse (2.5-100 ng/ml). Within certain limits, a lower total amount of cAMP and progesterone was accordingly released in response to the two FSH pulses when the concentration of the first pulse was increased. This refractoriness declined within a few hours as shown in experiments with extended pulse intervals. Two short and separate FSH pulses also evoked a higher combined response than did a single long FSH pulse lasting the whole time period. In these cases the cells thus responded with a lower total cAMP and progesterone release when exposed to a higher amount of FSH. Clinical trials on i.m. versus pulsatile i.v. FSH administration to anovulatory women have shown a similar relationship between FSH dose and effect, though other parameters were measured than those in the present study.

Basal gonadotropin hormone release rates during the period of selective follicle-stimulating hormone release in the juvenile female rat

There are situations in which adult female rats release increased amounts of follicle-stimulating hormone (FSH) independent of increased luteinizing hormone (LH) release. This results from, at least in part, a selective increase in the basal FSH release rate. We investigated whether an increase in the basal FSH release rate is contributory to the rise in serum FSH levels which occurs independent of a rise in serum LH levels in the immature female rat. Rats had high serum FSH concentrations on days 7 and 15 after birth, low serum FSH levels on day 23, and low serum LH levels on all three days. In contrast, anterior pituitary gland (APG) FSH and LH concentrations and contents increased from day 7 to day 15 and the contents increased further from day 15 to day 23. Similarly, basal FSH and LH release rates per mg APG or per APG, as assessed by measurement of FSH and LH released into culture medium containing APG(s) from different aged rats, increased from day 7 to day 15 but did not increase further between days 15 and 23. The results indicate that unlike situations observed to date in adult female rats, a mechanism(s) other than an increase in the basal FSH release rate is involved in selective FSH release in the immature female rat.

Seasonal effects on ovarian folliculogenesis in rhesus monkeys.

Reproductive performance is reportedly reduced in some rhesus monkeys during the summer months, even when environmental conditions are controlled. The mechanism(s) underlying this phenomenon remain unknown. We noted that the pattern of folliculogenesis appeared to be altered in rhesus monkeys that continued to exhibit ovulatory menstrual cycles during the "nonbreeding" season. This study was designed to investigate the effect of season on development of the dominant follicle (DF) and upon levels of serum gonadotropins and sex steroids in animals maintained in a controlled environment. Forty-four menstrual cycles were evaluated from October, 1982 to October, 1983. Animals were housed individually in controlled light (12L:12D) and temperature (22-25 degrees C). A DF was identified by laparoscopy on Day 6 of the cycle in only 45% of cycles during the months of May through September, compared with 87.5% the remainder of the year. No effect of season was detected on either the length of the menstrual cycle or luteal phase, mean follicular diameter, or the percentage of ovulatory cycles. During the follicular phase, amounts of follicle-stimulating hormone (FSH) in peripheral sera were depressed, whereas those of luteinizing hormone (LH) were consistently elevated. Amounts of circulating estradiol were similar between groups. However, serum concentrations of progesterone were markedly reduced in the summer. Development of the DF appeared to be delayed in the early follicular phase during the summer months in those rhesus monkeys that had ovulatory menstrual cycles. This delay was accompanied by an alteration in the FSH to LH ratio. Although most cycles were ovulatory, altered follicular development resulted in deficient luteal function.

Regulation of ovarian follicular growth and steroidogenesis by low-amplitude LH pulses.

A perifusion culture system controls the delivery of regulatory agents such that their concentration in the culture chamber is known at each and every point in time. The concentration in the culture chamber is predicted by the following equation: C(t) = Cf + (Ci - Cf)e(-R.t)/V, where C(t) is concentration in culture chamber (CC) at time t, Cf is concentration in holding flask (HF) (final CC concentration at t = infinity), Ci is initial CC concentration (t = 0), R is rate of media delivery from HF to CC (ml/h), V is volume of medium in CC (ml), and t is time (h). With this perifusion culture system, metestrous rat ovaries were exposed to tonic levels of follicle-stimulating hormone (FSH) and either tonic levels or hourly pulses of luteinizing hormone (LH). Both groups, however, received the same amount of FSH and LH. Compared with tonic levels, hourly pulses of LH increased estradiol-17 beta and suppressed testosterone secretion. In addition, pulsatile LH caused 1) a reduction in the atresia of small and midsized antral follicles, 2) an increase in atretic large follicles, and 3) an increase in the percent of growing midsized follicles. These results clearly demonstrate that ovarian responses depend on the pattern of LH stimulation. Since the LH pulses used in this study mimic in vivo metestrous levels, the LH pulses may be important in controlling ovarian function in vivo. The mechanism by which the ovary can distinguish between tonic and pulsatile stimuli remains to be determined.

Gonadotrophin release by gonadotrophs incubated with gonadotrophin-releasing hormone is independent of intracellular cAMP accumulation.

Rat pituitary cells were dispersed with trypsin and separated by sedimentation at unit gravity. The distributions of prolactin (Prl), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were determined, and two enriched cell populations (mammotrophs and gonadotrophs) were subsequently cultured. During a 4 h incubation, gonadotrophin-releasing hormone (GnRH) stimulated the release of LH and of FSH by both the unfractionated population and the enriched gonadotrophs; the magnitude of this stimulation increased with the length of the pre-culture periods, and the amount of LH released into the medium correlated strongly with the amount of FSH, whatever the length of the pre-culture period. The cellular cAMP content was also enhanced during the 4 h incubation, but no correlation was found between the hormone release and the cAMP accumulation. Furthermore, during the first 30 min of incubation with GnRH there was no increase of cellular cAMP, whatever cell population used. We conclude that the gonadotrophin release was independent of the cAMP accumulation observed in pituitary cells several hours after stimulation by GnRH; consequently, the late increase in the nucleotide is suggested to be a non-specific secondary process.

Selective release of follicle-stimulating hormone during the period of ovulation induced by human chorionic gonadotrophin in dioestrous rats.

Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183, Japan (Received 2 May 1977) When an amount of human chorionic gonadotrophin (HCG) sufficient to cause ovulation is given to 4-day cyclic rats on the day of dioestrus, premature ovulation is induced the next morning (Eto &amp; Imamichi, 1955). The pattern of release of follicle-stimulating hormone (FSH) responsible for the initiation of follicular maturation of the next set of follicles (Schwartz, 1969; Welschen &amp; Dullaart, 1976) after HCG-induced ovulation has not been previously evaluated. The present communication is concerned with this problem and indicates that a large amount of FSH is released within 12 h of administration of HCG, with only a small concomitant rise in the concentration of luteinizing hormone (LH). Adult female Wistar rats were maintained under a 14 h light : 10 h darkness schedule (lights on 05.00 h), and those showing three or

Binding of follicle-stimulating hormone by homogenates of testes of photostimulated white-crowned sparrows, Zonotrichia leucophrys gambelii

Homogenates of testes of the white-crowned sparrow bind specifically with 125I-labeled rat FSH (follicle-stimulating hormone). The binding is competitively inhibited by unlabeled rat FSH and PMSG (pregnant mare serum gonadotropin) but not by purified rat LH (luteinizing hormone). Crude gonadotropin preparations also inhibit binding but the rates of inhibition are fully explained by amounts of FSH in these preparations. The testes of photosensitive birds with resting testes were found to bind about 4 × 10 −15 moles of 125I-labeled rat FSH per milligram of tissue. The binding per milligram of tissue decreases during photoperiodically induced testicular growth, although the total binding capacity increases during the first 3 weeks of photoperiodic stimulation. Thereafter it increases no further although the weight of the testes continues to increase rapidly. With further development, a specific and sensitive radioreceptor assay of avian FSH, using a testicular homogenate of the white-crowned sparrow as the receptor, may be possible.

THE URINARY EXCRETION OF GONADOTROPHINS BY SHEEP: THE EFFECT OF SOME NUTRITIONAL FACTORS ON THE EXCRETION OF GONADOTROPHINS BY CASTRATED MALE SHEEP.

SUMMARY Male castrated Merino sheep were fed indoors on a dry ration or grazed on a good quality pasture. Despite the much greater urine volumes excreted by the grazing animals, the mean daily rates of excretion of total gonadotrophic activity and follicle-stimulating hormone (FSH) were very similar in the two groups. Corresponding levels of excretion of luteinizing hormone (LH) were very variable, owing apparently to deficiencies in the assay technique. When sheep were fed indoors on freshly cut grass, the urine output was almost three-quarters of that of grazing animals but the rate of excretion of total gonadotrophic activity and of FSH was considerably greater than that of grazing animals. The daily output of urine by sheep fed indoors on a dry ration was adjusted to equal that of grazing sheep. Although the amounts of total gonadotrophic activity were smaller than those in the previous experiments, the amounts of FSH excreted were the highest recorded in the entire investigation. The possibility of a temporal fluctuation in the excretion of gonadotrophins is discussed.

The role of the pituitary hormones in hyperplasia of the mammary glands

Combined administration of estrogens and prolactin did not induce any hyperplasia of the mammary glands of female suckling rats. However, combined administration of estrogens and gonadotropic hormones regularly caused a marked hyperplasia of the mammary glands. The extent of hyperplasia was connected with the amount of follicle-stimulating hormone administered, but did not depend upon the dose of the luteinizing hormone given; this points to the decisive role played by the follicle-stimulating hormone in the mammary gland hyperplasia occurring in female suckling rats.