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PubMed1993

Human recombinant inhibin A and testosterone act directly at the pituitary to suppress plasma concentrations of FSH in castrated rams.

The roles of inhibin and testosterone in the negative feedback control of the secretion of FSH were explored in experiments using castrated rams administered human recombinant inhibin A (hr-inhibin) and testosterone propionate (TP). Two experiments were conducted in the non-breeding season. In experiment 1, two groups of long-term castrated rams (wethers) were treated with an i.v. injection of either vehicle or hr-inhibin in two doses (25 and 50 micrograms) given 2 weeks apart. Plasma concentrations of FSH, measured by radioimmunoassay, were suppressed significantly (P < 0.01) and equally by both doses of hr-inhibin with a mean (+/- S.E.M.) maximal suppression of FSH of 19.9 +/- 2.60% occurring 6-10 h after injection. In experiment 2, hypothalamo-pituitary disconnected (HPD) wethers given 125 ng gonadotrophin-releasing hormone (GnRH) every 2 h, were treated with vehicle or 25 or 50 micrograms hr-inhibin before or after treatment (32 mg/day) with TP. A cross-over design was used so that each wether was treated with vehicle and hr-inhibin. Treatment with TP significantly (P < 0.001) suppressed plasma concentrations of FSH by 56%. Both doses of hr-inhibin were similarly effective in significantly (P < 0.05) suppressing plasma concentrations of FSH causing a mean suppression of 31.1 +/- 5.60% 6-10 h after injection. The suppressive effect of hr-inhibin was significantly (P < 0.05) increased when the wethers were treated with TP to a mean suppression of 50.7 +/- 5.6% 6-10 h after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Suppression of basal secretion of FSH inhibits follicular development and maturation during the oestrous cycle of the rat.

The role of basal FSH secretion during the rat oestrous cycle in regulating ovulation was examined by suppressing FSH secretion using charcoal-treated porcine follicular fluid (pFF). Although 0.5 ml pFF given at 05.00 and 11.00 h on the day of pro-oestrus had no effect on ovulation, 0.5 ml pFF given five times at 6-h intervals from 11.00 h on dioestrus to 11.00 h on pro-oestrus completely eliminated ovulation on the morning of the next oestrus. When 0.25 ml pFF was given on the same schedule, all animals ovulated a significantly decreased number of oocytes (9.0 +/- 0.8) at the next oestrus. During the period of pFF treatment, the number of follicles capable of ovulating in response to human chorionic gonadotrophin (hCG) decreased (7.6 +/- 0.7 at 05.00 h on pro-oestrus) and plasma levels of oestradiol showed a peak level 6 h later than in controls treated with 0.5 ml steroid-free porcine serum. Treatment with pFF suppressed plasma FSH concentrations in a dose-dependent manner, although plasma LH was inhibited irregularly. Supplementary administration of LH throughout the treatment period and 0.5 ml pFF resulted in ovulation of one to three oocytes in response to hCG in only three out of ten animals. These results suggest that basal secretion of FSH during the rat oestrous cycle plays an essential role in follicular development and maturation towards ovulation, and that the levels of FSH secretion may contribute to the maturation of normal numbers of follicles for ovulation.

Animals↗
PubMed1994

FSH and LH up-regulate epidermal growth factor receptors in rat granulosa cells.

Epidermal growth factor (EGF) modulates ovarian folliculogenesis and steroidogenesis and its binding sites have been demonstrated in the ovary. We investigated the localization of EGF-binding sites in the rat ovary, and the effects of FSH and LH on EGF binding to cultured granulosa cells. Autoradiographic localization of 125I-labelled mouse EGF-binding sites was demonstrated in the granulosa and luteal cells. Displacement study and Scatchard analysis showed that a single class of specific binding sites for 125I-labelled mouse EGF was present in the granulosa cells, obtained from the ovaries of immature rats treated with diethylstilbestrol. The number of binding sites and the apparent dissociation constant were 4336 binding sites/cell and 3.42 pmol/l respectively. The granulosa cells were cultured for 48 h at 37 degrees C in medium alone or with increasing amounts of ovine FSH (oFSH; 1-1000 micrograms/l). FSH treatment increased 125I-labelled mouse EGF binding to the granulosa cells in a dose-dependent manner. After culture with oFSH (100 micrograms/l) for 48 h, the cells were cultured in medium alone or with increasing amounts of ovine LH (oLH; 1-1000 micrograms/l) for an additional 48 h. LH treatment also increased 125I-labelled mouse EGF binding in a dose-dependent manner, compared with the control. However, neither FSH nor LH altered receptor-binding affinity. Furthermore, after culture with oFSH (FSH-primed) or oFSH followed by oLH (LH-primed), tissue plasminogen activator (tPA) activities in the conditioned media were examined by fibrin autography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Pharmacokinetics and pharmacodynamics of recombinant and urinary human FSH in the male monkey (Macaca fascicularis).

A dose-finding study was performed in adult male monkeys (Macaca fascicularis) to evaluate the pharmacokinetics and pharmacodynamics of a recombinant human FSH preparation (rhFSH). Groups of five monkeys were randomly assigned to receive single i.m. injections of 0.9% (w/v) NaCl (diluent), 6, 12 or 24 IU rhFSH/kg or 24 IU urinary human FSH/kg (uhFSH). The doses were based on an in vivo ovarian weight gain assay. Blood samples were collected 24 h before and immediately prior to injections, and 4, 8, 12, 24, 72 and 96 h after injections for determination of serum levels of immunoactive FSH by fluoroimmunoassay, bioactive FSH by an in vitro Sertoli cell assay, and inhibin and testosterone by radioimmunoassay. Inhibin was chosen as a marker for in vivo hFSH activity, since the secretion of inhibin in male monkeys is under the control of FSH. Administration of hFSH resulted in dose-related increases in serum hFSH concentrations. rhFSH and uhFSH exhibited similar pharmacokinetics. Comparable findings were obtained when serum samples were analysed for in vitro FSH bioactivity. Maximum serum hFSH levels were obtained 4-6 h after administration and the elimination half-life of hFSH was on average 18-22 h. The serum pharmacokinetics of rhFSH were linear within the dose range explored. Baseline inhibin concentrations varied significantly between groups. However, when the changes in inhibin concentrations were normalized to the baseline values (per cent change, area under curve and maximum inhibin level), a dose-dependent stimulatory effect of rhFSH on serum inhibin was evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Effects of placing micro-implants of melatonin in the pars tuberalis, pars distalis and the lateral septum of the forebrain on the secretion of FSH and prolactin, and testicular size in rams.

Previous studies involving the placement of microimplants of melatonin in the brain in sheep exposed to long days have provided evidence that melatonin acts within or close to the mediobasal hypothalamus (MBH) to mediate the effects of daylength on cycles in reproduction, moulting and other seasonal characteristics. To extend these observations, groups of Soay rams have now been treated with micro-implants of melatonin placed in the pars tuberalis (PT) and pars distalis (PD) of the pituitary gland, and in the lateral septum of the forebrain (septum). The PT and septum are potential target sites for the action of melatonin based on the localized binding of iodomelatonin assessed by in situ autoradiography. The animals were initially exposed to alternating 16-week periods of long days (16 h light: 8 h darkness; 16L:8D) and short days (8L:16D) to entrain the seasonal cycles. The treatments were started at 10 weeks into a period of long days when the animals had a physiology normally observed in summer (low blood plasma concentrations of FSH and high concentrations of prolactin), and they remained under long days throughout the experiments. In experiment 1, animals received micro-implants of melatonin placed in the PT (n = 6) or PD (n = 4), or received empty implants in similar sites (n = 4) or no surgery (n = 4; total control, n = 8). In experiment 2, groups of animals received microimplants of melatonin placed in the lateral septum (septum, n = 7) or received corresponding control treatments (total control, n = 8). The micro-implants consisted of 22 gauge stainless-steel needles with melatonin fused inside the tip. They were inserted bilaterally in the selected sites and left in place for 14 weeks. The biological effects of the treatments were assessed by measuring the changes in the blood plasma concentrations of FSH and prolactin, growth of the teses and moulting of the pelage over a period of 28 weeks (14 weeks treatment and 14 weeks post-treatment). The administration of melatonin in the PT, but not in the PD or septum, affected the photoperiodically induced cycle in the secretion of FSH and prolactin. In the PT group there was no significant change in the plasma concentrations of FSH during the treatment with melatonin, but there was a significant (P < 0.001, ANOVA) decrease in the levels of FSH after the treatment associated with premature regression of the testes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Changes in the suppressive effects of recombinant inhibin A on FSH secretion in ram lambs during sexual maturation: evidence for alterations in the clearance rate of inhibin.

We have investigated the effectiveness of human recombinant inhibin A (hr-inhibin A) to suppress the secretion of follicle-stimulating hormone (FSH) in ram lambs from 1 to 18 months of age. Seventeen rams (nine castrated, eight intact) were used. At 1, 3, 6, 9, 12 and 18 months of age the rams were given an i.v. injection of either vehicle or hr-inhibin A (0.64 microgram/kg). Blood samples were taken over 24 h. Plasma concentrations of FSH were suppressed in castrated and intact rams following injection of hr-inhibin A with maximal suppression occurring 6 h after injection. Vehicle injection had no effect. At 12 months of age the suppression in FSH was most rapid in castrated rams and was maximal in intact rams. The clearance rate of inhibin was greatest at older ages but during the period of seasonally induced testicular activity, there was a significant decrease in the inhibin clearance. The testicular weight was reduced in rams treated with hr-inhibin A, indicating the importance of FSH for testicular development during the pubertal period. There was no effect of hr-inhibin A on plasma concentrations of luteinizing hormone. We conclude that inhibin is capable of suppressing the secretion of FSH in rams from 1 month of age onwards and that the pituitary gland becomes maximally responsive to the actions of inhibin by the age of puberty.

Aging↗
PubMed1999

Inhibin B is a more sensitive marker of spermatogenetic damage than FSH in the irradiated non-human primate model.

This study evaluated the effect of bilateral testicular irradiation (2 Gy) on reproductive hormones, testicular volume (TV) and sperm parameters in six adult cynomolgus monkeys. Hormone levels (FSH, inhibin B and testosterone (T)) were determined to find the most valuable endocrine marker of irradiation-induced damage. All parameters were analysed at weekly intervals for 14 weeks. Histological evaluation of both testes was performed at week 14 after irradiation when one monkey was castrated and at week 27 when the remaining five monkeys were bilaterally biopsied. A decrease in body weight, TV (30% of the pre-treatment size) and sperm count was observed after irradiation. Severe oligozoospermia was achieved throughout the study but azoospermia was recorded only occasionally. Histological evaluation revealed a heterogeneous picture with patchy arrangement of seminiferous tubules containing advanced germ cell types. An increase (P<0.05) in FSH levels and, to a lesser degree also in T levels, occurred several weeks after irradiation. Inhibin B levels showed a sharp decline (P<0.001) as soon as 1 week after irradiation. FSH and inhibin B did not return to baseline levels during the observation period. A negative correlation was found between FSH and inhibin B values (r=-0.35, P<0.001). Inhibin B correlated positively with testis volume (r=0.73, P<0.001) and sperm counts (r=0.55, P<0.01). In conclusion, this study shows that inhibin B represents an early and more sensitive marker of testicular damage than FSH. Furthermore, the rapid fall of inhibin B after irradiation suggests that this hormone is a direct parameter of premeiotic germ cell proliferation.

Animals↗
PubMed1999

Antiprogestins RU486 and ZK299 suppress basal and LHRH-stimulated FSH and LH secretion at pituitary level in the rat in an oestrous cycle stage-dependent manner.

We have previously shown that administration of antiprogestin (AP) type II RU486 to ovariectomized (OVX) rats on the morning of pro-oestrus decreases the magnitude of preovulatory gonadotrophin surge. This suggests that the effect of RU486 on LHRH-dependent gonadotrophin release may be independent of its ability to block progesterone actions. The aim of the present research was to study the possible site of RU486 action and to determine whether the gonadotrophin suppressive effect of APs RU486 and ZK299 is dependent on the oestrogen background. Intact or OVX rats in the morning of pro-oestrus were injected s.c. with 4 mg of RU486 or ZK299 (AP type I) at 0900 h on pro-oestrus. At 1830 h, serum concentration of FSH and LH and median eminence (ME) content of LHRH were determined. In the second experiment, the effect of RU486 and ZK299 on pituitary responsiveness to LHRH (100 ng, i.p.) and ME content of LHRH at 1830 h pentobarbital-blocked intact or OVX rats was evaluated. In the last study, the anterior pituitary release of FSH and LH from pro-oestrus or metoestrus donors incubated with or without LHRH (1, 10 or 100 nM) in the presence or absence of APs (20 nM) was evaluated. Both APs reduced serum FSH and LH levels at 1830 h on pro-oestrus in intact and OVX rats. The suppressive effect on gonadotrophin release brought about by AP treatment was also evidenced in PB-blocked intact and OVX rats. This suggested that the inhibitory effect of APs occurred, at least in part, at pituitary level. Furthermore, in the absence of the natural ligand, APs significantly reduced basal and LHRH-stimulated FSH and LH release from pro-oestrous but not from metoestrus pituitaries. In conclusion, these experiments have shown, both 'in vivo' and 'in vitro', that APs RU486 and ZK299 have suppressive effects at pituitary level on basal and LHRH-stimulated FSH and LH secretion, regardless of their antiprogestagenic activity, in pro-oestrus but not in metoestrus.

Analysis of Variance↗
PubMed2000

Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula.

The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters. In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre- and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis. We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 degrees C or 4 degrees C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.

Adenylyl Cyclases↗
PubMed2003

Evaluation of relative roles of LH and FSH in regulation of differentiation of Leydig cells using an ethane 1,2-dimethylsulfonate-treated adult rat model.

The relative role of LH and FSH in regulation of differentiation of Leydig cells was assessed using an ethane 1,2-dimethylsulfonate (EDS)-treated rat model in which endogenous LH or FSH was neutralized from day 3 to day 22 following EDS treatment. Serum testosterone and the in vitro response of the purified Leydig cells to human chorionic gonadotropin (hCG) was monitored. In addition RNA was isolated from the Leydig cells to monitor the steady-state mRNA levels by RT-PCR for 17alpha-hydroxylase, side chain cleavage enzyme, steroidogenic acute regulatory protein (StAR), LH receptor, estrogen receptor (ER-alpha) and cyclophilin (internal control). Serum testosterone was undetected and the isolated Leydig cells secreted negligible amount of testosterone on stimulation with hCG in the group of rats that were treated with LH antiserum following EDS treatment. RT-PCR analysis revealed the absence of message for cholesterol side chain cleavage enzyme and 17alpha-hydroxylase although ER-alpha and LH receptor mRNA could be detected, indicating the presence of undifferentiated precursor Leydig cells. In contrast, the effects following deprival of endogenous FSH were not as drastic as seen following LH neutralization. Deprival of endogenous FSH in EDS-treated rats led to a significant decrease in serum testosterone and in vitro response to hCG by the Leydig cells. Also, there was a significant decrease in the steady-state mRNA levels of 17alpha-hydroxylase, cholesterol side chain cleavage enzyme, LH receptor and StAR as assessed by a semiquantitative RT-PCR. These results establish that while LH is obligatory for the functional differentiation of Leydig cells, repopulation of precursor Leydig cells is independent of LH, and also unequivocally establish an important role for FSH in regulation of Leydig cell function.

Animals↗
PubMed1983

Serum profiles of LH, FSH and prolactin from 10 weeks of age until puberty in gilts.

To characterize the secretory patterns of luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) during prepubertal development of the gilt, blood samples were collected at 20-min intervals for 4 h once a week from four littermate gilts 10 to 18 wk of age and from another group of four littermate gilts 19 to 25 wk of age. Puberty occurred in the latter group during wk 25. Serum concentrations of LH, FSH and PRL were averaged for each 4-h sampling period within each gilt, and any single value greater than one standard deviation above the mean for that period was identified as a secretory spike. Mean LH was greater at 16 wk of age than during wk 11, 12 and 13, and serum LH levels were higher at 25 than 22 wk of age. Frequency and magnitude of LH spikes were greatest at 16 wk in the group of gilts 10 to 18 wk of age, but magnitude of LH spikes did not change from 19 to 25 wk. The frequency of FSH secretory spikes did not change in gilts from 10 to 25 wk of age. No changes in mean serum concentrations of PRL, frequency of PRL spikes and magnitude of PRL spikes were observed during prepubertal development. Spikes of FSH and PRL occurred with more than random synchrony throughout the study. Spikes of LH and FSH or LH and PRL were highly synchronized during early prepubertal development (10 to 18 wk), but less synchronized in gilts 19 to 25 wk of age.

Aging↗
PubMed1984

Pituitary responsiveness to GnRH, hypothalamic content of GnRH and pituitary LH and FSH concentrations immediately preceding puberty in gilts.

To determine whether pituitary concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH) or hypothalamic content of gonadotropin releasing hormone (GnRH) change before puberty, 40 prepubertal gilts averaging 7 mo of age were slaughtered before or on the second, third or fourth day after relocation and boar exposure. Some gilts responded to relocation and boar exposure as indicated by swollen vulvae, turgid uteri and enlarged ovarian follicles at the time of slaughter. Pituitary concentrations of LH and FSH and hypothalamic content of GnRH were similar between gilts that responded to relocation and boar exposure and gilts that did not respond. In addition, boar exposure and relocation had no effect on pituitary concentrations of LH and FSH or on hypothalamic content of GnRH. To determine whether pituitary responsiveness to GnRH changes before puberty, a third experiment was conducted in which 72 gilts were injected with 400 micrograms of GnRH either before or on the second, third or fourth day after relocation and boar exposure. In gilts that subsequently responded (i.e., ovulated) as a result of relocation and boar exposure, pituitary responsiveness to GnRH was reduced as compared with gilts that failed to ovulate after relocation and boar exposure. Peak concentrations of serum LH after GnRH injection were 4.6 +/- 1.3 vs 9.8 +/- .8 ng/ml for responders vs nonresponders. Peak serum FSH after GnRH injection was also lower for responders than for nonresponders (29.5 +/- 4.2 vs 41.2 +/- 2.4 ng/ml). When compared with controls, relocation and boar exposure did not significantly affect GnRH-induced release of LH and FSH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Ovarian responses to intramuscular or intravenous administration of prostaglandin F2 alpha in control and FSH-treated beef heifers.

Sixty Simmental crossbred heifers 18 to 20 mo of age were detected in estrus and assigned at random to a 2 x 2 factorial design study with 30 controls, and 30 given FSH. Half of each group was given prostaglandin F2 alpha (PGF) i.v. and the rest i.m. Injections of follicle-stimulating hormone were started on d 7 to 14 of an estrous cycle and continued for 5 d or until ovariectomy; PGF was administered either i.v. or i.m. at 48 (25 mg) and 60 (15 mg) h after the initial FSH injection. Control females received a similar PGF treatment on a day between d 9 and 15 of the estrous cycle. Blood samples were collected from all animals immediately before PGF administration and every 12 h thereafter until ovariectomy. Within each of the four experimental subgroups, ovariectomies were performed at either 24, 48 or 72 h (five/time group) after initial PGF injection. Ovarian and corpus luteum (CL) weights were recorded as well as number and size of follicles and number of ovulations. Regression of the CL was slower (P less than .05) after administration of PGF i.v. than i.m. (CL weight was 2.6 vs 3.3 +/- .2 g for i.m. and i.v. groups, respectively). Exogenous FSH increased estradiol-17 beta (E2) concentrations, and FSH-treated heifers had more (P less than .05) early ovulations than control heifers did. Ovulations in FSH-treated heifers had begun to occur by 24 h after i.v. and i.m. PGF injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Effect of exogenous estrogens on LH and FSH secretion in women with hypothalamic amenorrhea.

The effect of estradiol on FSH and LH secretion in 5 women with hypothalamic amenorrhea are presented. The functional capacity of the pituitary to secrete FSH and LH had been proved by testing with synthetic luteinizing hormone-releasing hormone (LH-RH) 100 mug i.m. The thyroid and adrenal functions were normal. In 3 patients estrogens were low-normal and in the other 2 extreme hypoestrogenism was found. Twelve days after the appearance of withdrawal bleeding each patient was given 10 mg estradiol benzoat (EB) i.m. In 3 patients a significant increase in the LH and a slightly smaller increase in the FSH concentration were noted, with an LH peak 60 to 84 hours after injection of EB. The first of these 3 patients became pregnant, in the second the biphasic BBT curve, urine pregnanediol excretion above 2.5 mg/24 hr and the histological finding of secretory endometrium indicated that ovulation had been successfully induced, while in the third patient, despite a satisfactory increase in the LH and FSH concentration, ovulation could not be induced. In the remaining 2 patients no increase in the LH and FSH concentrations was noted even as late as 96 hours after the injection of EB. In these women bleeding began on the 18th and 22nd day of the cycle, respectively, when histological examination revealed proliferative endometrium. The first 3 cases are classified as hypothalamic amenorrhea with dysfunction of the cyclic centre and the other 2 as hypothalamic amenorrhea with dysnfunction of the tonic centre. The effect of exogenous estrogens in patients with hypothalamic amenorrhea depends both on the functional capacity of the hypophysis and the capacity and condition of the tonic and cyclic centres in the hypothalamus.

Adult↗
PubMed1978

Serum LH and FSH following passive immunization against circulating testosterone in the intact male rat and in orchidectomized rats bearing subcutaneous silastic implants of testosterone.

Subcutaneous Silastic implants were designed to release quantities of testosterone approximating that produced by the rat testis and appropriate testosterone treatment was found to produce a physiologic inhibition of both LH and FSH secretion in orchidectomized rats. In rats bearing such testosterone implants, intravenous injection of an ovine anti-testosterone serum (0.3 cc) was sufficient to completely abolish the inhibitory effects of the testosterone implant for a period of 3 days as judged by the development of typical post-castration increases in serum LH and FSH. When this dose of antiserum was administered to intact adult male rats, the increases in serum LH on days 1, 2, and 3 post-injection were approximately 19%, 15%, and 11% of those observed in untreated castrates. Increases in serum FSH in antiserum injected rats followed a pattern similar to that for serum LH but the response was slightly greater (19%, 23%, and 22% of the castrate response) and there was no indication of a decreasing effect during the three days following injection. In these experiments, passive immunization against testosterone in intact male rats produced a clearcut stimulation of both LH and FSH release, but produced no data to support the suggestion that the intact testis can secrete nonsteroidal compounds capable of producing a differential inhibition of FSH secretion.

Animals↗
PubMed1981

LH-induced testicular steroid secretion after FSH treatment in immature and young adult hypophysectomized rats.

Immature and young adult male rats were hypophysectomized on day 21 and 71 respectively. Beginning 2 days later, animals received five daily subcutaneous injections of 4 microgram/100 g body weight of NIAMDD-oFSH-13 or saline. On the sixth day the rats received either 15 microgram/100 g body weight of NIAMDD-oLH-21 or saline intraperitoneally and were decapitated 1 hr later. Serum levels of steroids were measured by radioimmunoassay. Serum steroid levels in animals receiving a saline injection on day 6 were low to undetectable and not affected by pretreatment. The serum steroid concentrations after LH challenge on day 6 were altered by FSH pretreatment. In immature rats, pretreatment with FSH resulted in a significant increase in 17 hydroxyprogesterone, androstenedione and testosterone. Progesterone and estradiol were unaffected, while 5 alpha dihydrotestosterone was elevated but not significantly. In young adults, FSH pretreatment resulted in increased levels of androstenedione, testosterone, and 5 alpha dihydrotestosterone, but not progesterone, 17 hydroxyprogesterone, or estradiol. These data suggest that FSH may play a role in stimulating cholesterol side chain cleavage activity, the 17 alpha hydroxylase, the C17-C20 lyase as well as the 17 beta hydroxysteroid dehydrogenase at puberty. Additionally, FSH may be involved in the maintenance of cholesterol side chain cleavage activity, the C17-C20 lyase and the 17 beta hydroxysteroid dehydrogenase in the adult rat.

Androstenedione↗
PubMed1975

Isolation and culture of FSH responsive Sertoli cells.

Methods for the isolation and culture of enriched populations of Sertoli cells from 20-60 day old rats are described. The identity of the Sertoli cells was verified by bright light and electron microscopy. Freshly isolated Sertoli cells specifically bound follicle stimulating hormone (FSH) but not luteinizing hormone (LH) and responded to FSH stimulation with dramatic increase in cyclic AMP level. Isolated Sertoli cells, maintained in culture for 11 days, showed no evidence of proliferation but retained their characteristic ultrastructural features and FSH binding ability. Incubation of cultured cells with FSH resulted in a significant stimulation of cyclic AMP and androgen binding protein (ABP). Since the freshly isolated or cultured cells were predominantly (greater than 80%) Sertoli cells, these results provide direct evidence that the Sertoli cells represent a primary target site for FSH activity in the testes. The culture method also provides a valuable in vitro model for the study of chronic effects of various agents on the Sertoli cell.

Animals↗
PubMed1993

Measurement of serum levels of exogenously administered FSH and LH during ovulation induction therapy.

We conducted a prospective study of blood levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) following daily intramuscular injection of human menopausal gonadotropin (hMG) containing equal proportions of FSH and LH. Blood samples were collected on alternate days and the resulting changes in the blood levels of the ovarian hormone estradiol were also monitored. Twenty-eight consecutive patients with polycystic ovary syndrome who were between the ages of 25 and 35 years and attending our infertility clinic for ovulation induction therapy and assisted pregnancy were studied. Polycystic ovary syndrome was diagnosed on laparoscopy and as evidenced by high serum LH which was three times greater than FSH in the follicular phase of the menstrual cycle. A male factor for infertility was excluded. Twenty-five out of 28 women (89.3%) receiving hMG responded to therapy by a rise in serum estradiol level (> 1200 pmol/l on day 9). Of the 25 women who responded to hMG, four had live single babies (16%). All four women showed a cumulative rise in mean serum FSH with treatment when measured by standard radioimmunoassay, reaching statistical significance on day 5 (p < 0.05). The remaining 21 who failed to become pregnant showed variable changes in mean serum FSH with a sharp rise on day 3 (p < 0.02) and a significant fall on day 7 (p < 0.02). However, mean serum LH measured by standard radioimmunoassay in all women remained unchanged throughout the period of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗