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PubMed1988

Effects of treatment of neonatal rats with highly purified FSH alone and in combination with LH on testicular function and endogenous hormone levels at various ages.

Factors which play a role in the regulation of testicular size in rats were investigated using neonatal animals treated with exogenous gonadotrophins for 2 or 3 weeks, starting on the day after birth. Effects on testis weight and various aspects of the pituitary-testicular axis were evaluated up to the age of 9 weeks. Daily treatment with human FSH (Metrodin; 0.15 U/g body wt) for 2 or 3 weeks, starting on the first day or 1 week after birth, resulted in enlargement of the testes, increased testicular content of inhibin and a suppression of pituitary and plasma FSH. The relative increase of testis weight decreased after cessation of treatment. Injections of human FSH combined with administration of human LH (Pergonal) for 3 weeks, starting on the first day after birth, resulted in larger testes immediately after treatment. In addition, an increased amount of interstitial tissue was observed in these animals. Pituitary and plasma FSH and LH were suppressed after this treatment, while the growth of the accessory sex organs was significantly stimulated. In animals treated with human FSH during the first 2 or 3 weeks of life, levels of rat FSH in blood samples collected at weekly intervals were significantly suppressed until the animals were killed at the age of 9 weeks. In the animals treated with human FSH and human LH, both FSH and testosterone concentrations were significantly lower than those in control animals between the ages of 4 and 9 weeks. At the age of 9 weeks testicular weights were still higher than those in control animals after these treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

Secretion rates and short-term patterns of gonadotrophin-releasing hormone, FSH and LH in the normal stallion in the breeding season.

Pituitary venous blood was collected by a painless nonsurgical cannulation method from five ambulatory stallions at 5-min intervals for 5-6 h during the breeding season. In four adult stallions, statistical analysis showed that pulses of gonadotrophin-releasing hormone (GnRH) and LH were coincident (P less than 0.01), as were pulses of FSH and LH (P less than 0.05). Furthermore, the patterns of changes in concentration of FSH and LH were highly correlated in each of the four stallions. However, seemingly ineffective pulses of GnRH were also observed, with 28% of GnRH pulses failing to induce a significant gonadotrophin pulse. In the four adult stallions the amplitude of pituitary venous gonadotrophin pulses varied markedly but no correlation with GnRH pulse amplitude was observed. Peak secretion of FSH, but not LH, during pulses was correlated with the length of the interpulse interval. Consequently, the ratio of FSH to LH during peaks was least (P less than 0.02) when the interpulse interval was 30 min or less. Thus, differential FSH and LH secretion was achieved within a constant steroid milieu. Two stallions had regular contact with oestrous mares, and in these horses the secretion of GnRH and gonadotrophins occurred almost continuously with rapid, rhythmic pulses superimposed upon a tonic background. Mean (+/- S.D.) interval between GnRH pulses was 31.4 +/- 9.8 min and 27.7 +/- 10.1 min. This secretory pattern was not observed in the two stallions which had infrequent contact with oestrous mares, although the small numbers precluded statistical testing of this apparent difference. No GnRH pulses were observed in one of these stallions, while in the other mean (+/- S.D.) GnRH pulse interval was 45.0 +/- 48.7 min, the large variance being partly due to rapid pulses during a period in which the stallion teased mares. The fifth stallion was pubertal, and GnRH and LH secretion occurred in 15 and 0% of samples respectively, while low levels of FSH secretion were observed in 37% of samples and jugular testosterone levels were immeasurably low. We conclude that there is a statistically significant synchrony between pulses of GnRH, LH and FSH in the pituitary venous blood of stallions. Furthermore, decreasing intervals between gonadotrophin pulses result in a significant reduction in secretion of FSH but not LH.

Animals↗
PubMed1990

Inhibitory effect of the uterus on plasma and pituitary FSH in rats.

Plasma concentrations of FSH and LH were measured in ovariectomized, ovohysterectomized, hysterectomized and sham-operated adult, non-pregnant rats at 3, 14, 21 and 28 days after operation. From day 21 after the operation onwards, there were higher concentrations of FSH in plasma in ovohysterectomized than in ovariectomized animals. The concentration of LH was not influenced by hysterectomy. The inhibitory response of FSH and LH to a single dose of oestradiol was not altered by any of the operations. By 2 weeks after surgery, pituitary FSH content had increased in ovohysterectomized animals compared with ovariectomized ones, but this difference was eliminated when ovohysterectomized animals were treated with crude uterine extract. Pituitary contents of LH and prolactin were not influenced by hysterectomy or by treatment with uterine extract, thus indicating the specificity of an inhibitory effect of the uterus on FSH levels. Treatment of hysterectomized and intact animals with uterine extract resulted in a reduction in the weight of the ovaries of 23-38% (P less than 0.05), indirectly showing the presence of an FSH-inhibiting substance in the extract. Fractionated uterine extract inhibited FSH synthesis by rat pituitary cells in vitro, but had no effect on LH synthesis. Chromatographic analysis indicated that the FSH-inhibiting substance in the uterus has a molecular weight of 10,000-20,000.

Animals↗
PubMed1991

Effect of basal and pulsatile LH release on FSH-stimulated follicle growth in ewes chronically treated with gonadotrophin-releasing hormone agonist.

Ewes chronically treated with gonadotrophin-releasing hormone (GnRH) agonist were used to investigate the importance of the peripheral concentration of LH in FSH-stimulated follicular development. Twenty-four Welsh Mountain ewes were treated with two agonist implants containing 3.3 mg buserelin. During week 6 of treatment all the ewes were given a 72-h continuous infusion of ovine FSH alone (3 micrograms/h) or FSH with large (7.5 micrograms)- or small (2.5 micrograms) amplitude pulses of ovine LH delivered at 4-hourly intervals. The importance of baseline LH throughout the FSH infusion was evaluated in six animals which were treated with a specific antiserum against bovine LH (LH-AS) 15-20 h before the start of FSH treatment. In the absence of LH-AS, infusion of FSH alone or with large or small pulses of LH stimulated the development of a normal number of small follicles (less than or equal to 2.5 mm in diameter) and large follicles (greater than 2.5 mm in diameter). These follicles had normal diameter and steroid secretion compared with control ewes on day 8 of the luteal phase. In contrast, the animals pretreated with LH-AS developed no follicles greater than 2.0 mm in diameter but the number of small follicles per ewe was significantly (P less than 0.05) increased. These results support the hypothesis that FSH in the absence of pulsatile LH release stimulates preovulatory follicular development in ewes treated with GnRH agonist. The follicular response to LH pulses of different amplitude is dependent on both the stage of development of the follicle and the peripheral concentration of FSH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Mechanisms responsible for suppression of FSH and LH during lactation in the rat.

Mechanisms responsible for suppression of FSH and LH secretion during lactation were investigated in rats, with special reference to the suckling stimulus and ovarian inhibin. Concentrations of immunoreactive inhibin in the peripheral plasma and bioactive inhibin in ovarian venous plasma were always low on days 3 and 5 of lactation in dams nursing eight pups, whereas values were always high on days 17 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups. There was an FSH surge within 48 h after removal of litters on days 3 and 5 of lactation in dams nursing eight pups, whereas plasma concentrations of FSH were unchanged within 48 h by removal of litters on days 17 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups. Plasma LH concentrations increased significantly compared with those of control animals within 24 h after removal of the litter on any day of lactation, regardless of the litter size. Plasma FSH levels increased within 6 h after bilateral or unilateral ovariectomy in lactating rats only on the days when plasma concentrations of inhibin were high before ovariectomy, such as day 17 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups, whereas the mean concentrations of plasma LH showed no significant increase within 12 h after bilateral ovariectomy in these lactating rats. Treatment with progesterone or oestradiol-17 beta after unilateral ovariectomy did not inhibit the increase in plasma FSH levels, while the increase in plasma concentrations of FSH after surgery was completely inhibited by injecting inhibin (porcine follicular fluid). Treatment with steroid hormones inhibited the basal levels of LH in unilateral ovariectomized lactating rats. Plasma FSH concentrations increased sharply within 6 h after a single i.v. injection of anti-inhibin serum on days 10, 15 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups, whereas only a small but significant increase in concentrations of FSH was noted 6 h after the antiserum treatment on day 5 of lactation in dams nursing eight pups. Concentrations of plasma LH were unchanged by treatment with antiserum in lactating rats throughout lactation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Induction of the gonadotrophin surge-inhibiting factor by FSH and its elimination: a sex difference in the efficacy of the priming effect of gonadotrophin-releasing hormone on the rat pituitary gland.

This study was designed to explore the efficacy of gonadotrophin-releasing hormone (GnRH) to antagonize the effect of gonadotrophin surge-inhibiting factor (GnSIF) on the timing of the induction by GnRH of the maximal self-priming effect on pituitary LH responsiveness. The GnSIF levels were increased by FSH treatment and reduced after gonadectomy. Female rats were injected s.c. with 10 IU FSH or saline (control) on three occasions during the 4-day cycle. Serial i.v. injections of GnRH (500 pmol/kg body weight) were administered to intact rats on the afternoon of pro-oestrus or 15-30 min after ovariectomy. Intact male rats were given 10 IU FSH and 500 or 2000 pmol GnRH/kg body weight on an equivalent time-schedule. Endogenous GnRH release was suppressed with phenobarbital. In intact female control rats, the timing of the maximally primed LH response was delayed as the GnRH pulse-interval increased. FSH treatment of female rats induced a suppression of the initial unprimed LH response and delayed the maximally primed LH response, which showed further delay as the GnRH pulse-interval was increased. When the pulsatile administration of GnRH was started 15-30 min after ovariectomy, the priming effect of GnRH did not change as the GnRH pulse-interval was increased in the saline-treated rats. However, FSH treatment caused a suppression of the unprimed LH response, a delay in the primed LH response and decreased the delay of the maximally primed LH response to GnRH when the GnRH pulse-interval was decreased. Increasing the interval between ovariectomy and the first GnRH pulse to 4 h diminished the efficacy of the FSH treatment: GnRH-induced priming was delayed by only one pulse instead of the two pulses in control rats. In intact males but not in orchidectomized rats, a self-priming effect was demonstrated during GnRH pulses which were 1 h apart. The effect of 2 nmol GnRH/kg body weight was the most pronounced. Compared with intact female rats, the timing of the maximally primed LH response was delayed by 1 h. FSH treatment did not affect the pituitary LH response to both dose levels of GnRH. It is concluded that FSH treatment increased the release of GnSIF by the ovary, then induced a state of low responsiveness of the pituitary gland to GnRH and subsequently delayed GnRH-induced maximal self-priming. The efficacy of GnRH to prime the pituitary gland was higher when GnSIF levels were decreasing after removal of the ovaries.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Polymorphism of human pituitary FSH: analysis of immunoreactivity and in vitro bioactivity of different molecular species.

Follicle-stimulating hormone is known to be highly heterogeneous in serum and in the pituitary. In the present study, we have partially separated different molecular species of human pituitary FSH and characterized their immunoreactivity and in vitro bioactivity. Pooled extracts of male (n = 15) and female (n = 9) human pituitary glands were chromatographed on a column of Sephacryl S-200 and FSH-containing fractions were fractionated by chromatofocusing in the pH range 4-6. FSH was measured in the individual fractions by an in vitro bioassay, based on the FSH-dependent aromatase activity of immature rat Sertoli cells, and by the following methods based on commercial kits: radioimmunoassay (RIA), immunofluorimetric assay (IFMA), immunoradiometric assay (IRMA), immunoenzymometric assay (IEMA). In each assay, the kit standard, calibrated against the 2nd International Reference Preparation (IRP) 78/549, and the International Standard (IS) 83/575 were run in parallel. The relative potencies of the kit standards in terms of IS 83/575 were: IFMA 3.08, IRMA 1.62, RIA 2.42, IEMA 1.45 and bioassay 1.14. After chromatofocusing, pituitary FSH eluted mostly in fractions with pH approximately 4.5, without sex-related differences. In both sexes approximately 25% of bioactive material showed a pI < 4 and eluted with 1 M NaCl. Although the same IS 83/575 was used in the various assays, the profiles of immunoreactive FSH were significantly different. The highest intermethod variability was observed in the case of male pituitary FSH. The relative biopotency of the different molecular species of FSH did not appear to change according to their pI but, rather, varied with the assay method and the standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Effects of recombinant human FSH in immature hypophysectomized male rats: evidence for Leydig cell-mediated action on spermatogenesis.

The mode of FSH actions within the testis was studied in immature hypophysectomized male rats by treatment with recombinant human FSH (recFSH, Org 32489). To elucidate the involvement of Leydig cells and androgens in the maintenance of spermatogenesis in FSH-treated hypophysectomized rats further, the recFSH treatment was given both alone and after destruction of Leydig cells with ethane-1,2-dimethane sulphonate (EDS). Three days after hypophysectomy (at 31 days of age) the rats were given one i.p. injection of vehicle or EDS and, 4 days later, they were implanted with osmotic minipumps releasing either 0.9% (w/v) NaCI or 1 IU recFSH/day. Recombinant FSH alone increased testicular weights 2.5-fold in 7 days (P < 0.01). The effect of FSH was similar in EDS-pretreated rats (P < 0.01). Testicular testosterone increased from 6.5 +/- 1.6 to 16.9 +/- 5.3 (S.E.M.) pmol/g tissue (P < 0.05) and serum testosterone from 0.12 +/- 0.02 to 0.22 +/- 0.03 nmol/l (P < 0.05) when the rats were treated with recFSH. EDS alone did not affect testicular testosterone but, when combined with recFSH, it totally abolished the stimulatory effect of FSH on testosterone. Testicular binding of 125I-labelled iodo human chorionic gonadotrophin (hCG) and 125I-labelled iodo recFSH was increased 2.5- and 2.1-fold respectively with recFSH treatment (P < 0.01). EDS, either alone or with FSH, abolished specific testicular hCG binding (P < 0.01), but had no effect on that of recFSH. However, FSH increased its own receptors only in animals not treated with EDS.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Manipulation of inhibin during the luteal-follicular phase transition of the primate menstrual cycle fails to affect FSH secretion.

The pattern of inhibin concentrations in blood during the menstrual cycle in primates has suggested an endocrine role of inhibin in the negative feedback control of FSH secretion during the luteal phase. Conversely, the fall in inhibin during the late luteal phase may play a role in the rise in serum FSH during the luteal-follicular phase transition. This hypothesis was examined by determining the effects of manipulation of inhibin on FSH secretion in stumptailed macaques. During the mid-luteal phase the putative inhibin feedback was inhibited by i.v. administration of 20 ml of ovine antiserum to human recombinant inhibin in 4 macaques. FSH secretion was unaffected during the initial 24 h period post-treatment and the timing of the rise in FSH which occurred during the subsequent luteal-follicular phase transition was normal. To determine whether the elevated serum concentrations of FSH observed during the early follicular phase could be reduced by administration of inhibin, 5 cyclic macaques were treated with 200 micrograms of recombinant human inhibin i.v. Serum FSH concentrations were unaltered. These results suggest that inhibin does not play a major role in modulating FSH secretion during the luteal-follicular phase transition.

Animals↗
PubMed1995

Differences in carbohydrate composition of FSH preparations detected with lectin-ELISA systems.

FSH is a glycoprotein containing N-linked carbohydrates which exhibit a variety of forms ranging from mono- to multibranched structures. Variation in glycosylation, particularly the degree of terminal sialylation, determines the half-life of the hormone and hence its in vivo bioactivity. The glycoform content of FSH preparations can differ according to the source (e.g. pituitary, urine), cell line (for rDNA-derived material) and selectivity of purification procedures, and may create difficulties in the preparation and characterization of standards and therapeutic products. In order to develop a simple method to detect changes in glycocomposition, an FSH ELISA was modified by the incorporation of lectins of recognized sugar specificity, and used to examine the terminal sugar composition of ampouled preparations of pituitary, urinary and rDNA-derived FSH. FSH was captured with a specific monoclonal antibody (MAb) and detected with either biotinylated anti-FSH MAb (ELISA) or the sugar-specific lectins (L-ELISA) from Triticum vulgaris (sialic acid, SA), Sambucus nigra (alpha 2,6-linked SA), Maackia amurensis (alpha 2,3-linked SA) or Ricinus communis (free terminal galactose; GAL). Relative estimates of the amounts of terminal SA, its different forms and GAL were derived from the L-ELISA/ELISA data compared with the highly sialylated 1st International Standard for pituitary FSH (IS) 83/575. All the FSH preparations had less SA than the IS with the ratio of alpha 2,3- and alpha 2,6-linked SA varying between preparations. The amounts of alpha 2,6-linked SA relative to the IS were not significantly different in the urinary and pituitary preparations whereas alpha 2,3-linked SA in all preparations was generally less than that of the standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗
PubMed1997

Enhancement of FSH bioactivity in vivo using site-specific antisera.

The ability of site-specific antipeptide antisera to enhance the biological activity of ovine FSH (oFSH) in vivo was investigated using hypopituitary Snell dwarf mice. These animals were shown to respond to increasing doses of oFSH (3.3-90 micrograms/day), administered in two daily injections over a 5-day treatment period, in a highly significant dose-dependent fashion. The responses measured were increases in uterine weight, ovarian weight and the index of keratinisation in vaginal smears. The dose-dependent response to oFSH confirmed the suitability of this animal model for these investigations and suggested the suboptimal dose of oFSH (20 micrograms/day) for use in enhancement studies. Five peptides derived from the beta subunit of bovine FSH (bFSH) (A, residues 33-47; B, 40-51; C, 69-80; D, 83-94; E, 27-39) were used to generate polyclonal antipeptide antisera. Of these peptides, only A and B produced an antiserum (raised in sheep) capable of recognising 125I-bFSH in a liquid phase RIA. Antisera prepared against peptide A or peptide B were found to significantly enhance the biological activity of 20 micrograms oFSH/day over a 5-day treatment period. The response to antipeptide antisera alone did not differ significantly from that observed in PBS-injected control animals, neither did the response to FSH alone differ from that observed in animals treated with FSH plus preimmune serum. Thus the enhanced responses are dependent upon the presence of FSH plus antipeptide antiserum. Peptides A and B are located in a region thought to be involved in receptor recognition, this may have implications for the mechanism underlying this phenomenon and/or the structure/function relationships of FSH. That FSH-enhancing antisera can be generated by immunisation of animals with peptides A and B suggests that it may be possible to develop these peptides as vaccines capable of increasing reproductive performance, such as ovulation rate. The high degree of sequence homology between ovine, bovine and porcine (and to a lesser extent human and equine) FSH in the region covered by peptides A and B suggests that these peptides could also be used to promote and regulate ovarian function in all of these species.

Amino Acid Sequence↗
PubMed1998

Characterisation, calibration and comparison by international collaborative study of international standards for the calibration of therapeutic preparations of FSH.

Therapeutic preparations of FSH, used primarily for treatment of infertility, are calibrated by in vivo bioassay against international standards (IS) derived from different sources deemed appropriate to their use according to pharmacopoeial monographs. Menotrophins, which have been used for several decades to treat infertility, have been calibrated against the IS for urinary FSH and LH (ISU) but are now being replaced by highly purified urinary FSH or rDNA-derived FSH (rFSH). The aim of this study was to evaluate two preparations of human rFSH and one preparation of highly purified urinary FSH as candidate WHO IS for bioassay in an international collaborative study by 27 laboratories in 12 countries, and to characterise them in a range of in vitro bioassays and immunoassays. The biological activity of the three candidate standards was confirmed by all laboratories using all assays contributed to the study. Dose-response relationships by in vivo bioassay for any of the candidate standards did not differ significantly from that for the ISU. Dose-response relationships obtained in in vitro bioassays and immunoassays were also broadly similar among these preparations although dose-response lines for some preparations appeared to be non-parallel in some immunoassays. For each of the three candidate IS, estimates of the relative potency in terms of ISU by in vivo bioassay did not differ significantly between laboratories. In contrast estimates by immunoassays and in vitro bioassays showed significant differences between laboratories. Estimates of relative potency of the highly purified candidate IS materials in terms of one another exhibited less inter-laboratory variability than estimates in term of ISU. Each of the candidate standards showed adequate stability to serve as an IS. On the basis of the results of this study rFSH (code 92/642) was established as the first IS for FSH, human, recombinant for bioassay with an assigned unitage of 138 IU per ampoule and urinary FSH (code 92/512) was established as the first IS for FSH, human, urinary (urofollitropin) for bioassay with an assigned unitage of 121 IU per ampoule, based on their respective calibration by in vivo bioassay in terms of ISU. These assignments of unitage maintain continuity of unitage for preparations in therapeutic use and also appear to be consistent with one another.

Biological Assay↗
PubMed2000

Effect of FSH and cell localization on dimeric inhibin-A secretion from bovine granulosa cells in culture.

We tested the hypotheses that the secretion of dimeric inhibin-A from cultured bovine granulosa cells is stimulated by FSH, and that antral cells secrete more inhibin-A than do mural cells. Cells from the antral or mural compartment of follicles were cultured in defined medium in two culture systems, and dimeric inhibin-A was measured by two-site ELISA or by Western immunoblotting. In the first culture system, dimeric inhibin-A secretion declined with time in culture, but was significantly (P<0.05) higher from antral than from mural cells (as was total inhibin-alpha measured by RIA). The secretion of dimeric inhibin-A and inhibin-alpha from antral but not mural cells was responsive to FSH. In the second culture system, dimeric inhibin-A secretion increased with time in culture, and was significantly stimulated by FSH, but FSH responsiveness was dependent on the concentrations of insulin in the culture medium. The major forms of inhibin-A secreted had molecular masses of approximately 58, 62, 103-116 and >116 kDa; the 32 kDa form was barely detectable. These different forms were all stimulated by FSH, but the >116 and 62 kDa forms were most responsive to FSH. We conclude that (i) FSH stimulates dimeric inhibin-A secretion from bovine granulosa cells, (ii) the 62 kDa form of inhibin-A may be more responsive to FSH than the 58 kDa form, and (iii) the spatial differentiation of granulosa cell function within the follicle previously observed for oestradiol secretion was also observed for inhibin-alpha and dimeric inhibin-A secretion.

Animals↗
PubMed2001

The fourth International Standard for Human Urinary FSH and LH: specificities of LH seminal vesicle weight gain assays in the collaborative study differ between laboratories.

The fourth International Standard for Human Urinary FSH and LH (IS; in ampoules coded 98/704) was compared with the third International Standard for Urinary FSH and LH (IS 71/264) by 10 laboratories in nine countries, using FSH and LH in vivo bioassays. Estimates of the FSH content of the IS by augmented ovarian weight gain assays were homogeneous within each laboratory and over all laboratories. The combined weighted geometric mean estimate of FSH content of the IS (with 95% fiducial limits) in terms of IS 71/264 was 71.9 (69.0-74.9) IU/ampoule. Although estimates by seminal vesicle weight gain (SVW) assays of the relative LH activities of the IS and IS 71/264 were homogeneous within laboratories, estimates were heterogeneous between laboratories. This indicated differences between the spectrum of LH isoforms in the IS and IS 71/264, which were obtained from different manufacturers, and differences between the specificities of SVW assays performed in different laboratories. The differences between the specificities of SVW assays appeared to be related to interactions among mean laboratory seminal vesicle weights, age and genetic strain of rat. The finding of inter-laboratory differences in the specificities of SVW assays is of some significance, as this assay method has been generally adopted by Pharmacopoeias for the control of the LH content of therapeutic products. The combined unweighted geometric mean estimate of LH content of the IS (with 95% fiducial limits) in terms of IS 71/264 by SVW and ovarian ascorbate depletion assays was 70.2 (61.7-80.0) IU/ampoule. Estimates of the FSH and LH content of ampoules of the IS kept at increased temperatures suggested that the IS would be adequately stable under normal storage conditions. On the basis of these results, the World Health Organization Expert Committee on Biological Standardization established the preparation in ampoules coded 98/704 as the fourth International Standard for Human Urinary FSH and LH, and assigned to the contents of each ampoule an activity of 72 International Units of urinary FSH and an activity of 70 International Units of urinary LH.

Animals↗
PubMed2002

Insulin and IGF-I are necessary for FSH-induced cytochrome P450 aromatase but not cytochrome P450 side-chain cleavage gene expression in oestrogenic bovine granulosa cells in vitro.

The earliest biochemical indicators of ovarian follicle deviation in cattle include lower oestradiol and free IGF concentrations in subordinate compared with dominant follicles. We determined if decreases in FSH, IGF-I or insulin cause decreased P450 aromatase (P450arom) or P450 cholesterol side-chain cleavage (P450scc) mRNA expression in oestrogenic bovine granulosa cells in vitro. In the first experiment, cells obtained from small follicles (2-5 mm diameter) were cultured in serum-free medium supplemented with physiological concentrations of FSH, IGF-I and insulin for 4 days. A decrease in specific hormone concentration was produced by replacing 70% of spent medium with medium devoid of FSH, insulin, or insulin and IGF-I on day 4 and again on day 5 of culture. Cultures were terminated on day 7. A reduction in FSH concentrations during the last 3 days of culture decreased P450arom and P450scc mRNA levels. A reduction in insulin reduced P450arom but not P450scc mRNA levels, and a reduction of both insulin and IGF-I concentrations further decreased P450arom mRNA levels and decreased P450scc mRNA levels. In a second experiment, cells obtained from small follicles (2-5 mm diameter) were cultured with insulin (100 ng/ml) without FSH for 4 days, and then insulin was withdrawn from the culture and FSH added for a further 3 days. The withdrawal of insulin decreased (P<0.02) oestradiol accumulation and reduced P450arom mRNA to below detectable levels, but did not affect P450scc mRNA levels. The addition of FSH transiently increased oestradiol secretion and P450arom mRNA levels, but P450arom mRNA levels were undetectable at the end of the culture period. The addition of FSH significantly enhanced P450scc mRNA levels and progesterone accumulation. These data demonstrated that a reduction of insulin-like activity reduced aromatase gene expression in bovine follicles without necessarily affecting progesterone synthetic capability, and thus may initiate follicle regression in cattle at the time of follicle divergence.

Animals↗
PubMed1982

Desensitization of FSH-responsive adenylyl cyclase in cultured immature Sertoli cells by homologous hormone.

Sertoli cell monolayers were prepared from 19-day-old rat testes. On day 7 of culture cells were incubated for 24 hr in the presence or absence of ovine follicle stimulating hormone (oFSH). Cells were harvested, and adenylyl cyclase responses of the membrane particles to FSH, human chorionic gonadotropin (hCG), isoproterenol, and fluoride (F-) were examined in the presence of either GTP or the nonhydrolyzable guanylyl nucleotide GMP-P(NH)P. Culturing the cells in presence of FSH caused a hormone specific desensitization of FSH-responsive adenylyl cyclase, whereas responses to isoproterenol and fluoride were unaffected. Activation of Sertoli cell adenylyl cyclase by GTP and GMP-P(NH)P showed no difference between cells preincubated with or without FSH, indicating that FSH did not change the activity of the G/F (or N) component or its interaction with the catalytic subunit of the adenylyl cyclase. FSH-responsive adenylyl cyclase in cultured Sertoli cells has been shown to be selectively desensitized by homologous hormone. The mechanism may involve alteration or loss of the FSH receptor or changes in the "coupling" of the FSH receptors to the G/F component of the adenylyl cyclase, since there was no alteration in the guanylyl nucleotide and fluoride activation.

Adenylyl Cyclases↗
PubMed1975

Effect of intermittent infusion of LH-releasing hormone of serum LH and FSH levels in immature male rats.

The effect of intermittent intravenous infusions of LH-RH on serum LH and FSH levels was studied in immature male rats. At the end of the infusion, serum LH and FSH levels were higher than those after saline infusion. One hr after the end of infusion of LH-RH, serum LH levels fell, reaching saline control values, but FSH levels remained higher. Moreover, a pulsative pattern of LH release but not of FSH, was obtained during the intermittent infusion with LH-RH. These findings indicate that under appropriate conditions after administration of LH-RH, it is possible to find high GSH levels without a concomitant rise of LH levels. The continued elevation of FSH may be explained by the longer biological half-life of FSH. Estradiol benzoate depressed the basal serum GSH level and augmented the basal serum GSH level and augmented LH release after intermittent infusion with LH-RH, indicating that estrogen modified FSH/LH ratio. The results suggest that discordance of plasma LH and FSH levels which is occasionally observed in some physiological conditions does not necessarily indicate the presence of another FSH-RH which is distinct from LH-RH decapeptide.

Animals↗
PubMed1995

[Effect of follicle-stimulating hormone (FSH) on protection or acceleration to recovery from spermatogenic damage induced by anti-cancer agents].

We investigated spermatogenic damage induced by anti-cancer agents in previous studies. The results showed that the damage to spermatogenesis induced by anti-cancer agents could be due to not only direct damaging effects on DNA synthesis but also a direct effect on Sertoli cell function. Thus, stimulating Sertoli cell function could protect against the damaging effects of anti-cancer agents on spermatogenesis, or stimulate recovery from impair spermatogenesis. We experimented with rats injected with the anti-cancer agents cisdiamminedichloroplatinum (CDDP) and adriamycin, which impair spermatogenesis, in order to examine this hypothesis. Follicle-stimulating hormone (FSH), which should stimulate Sertoli cell function in vivo, was selected, and the effects of FSH in protecting against damage or stimulating recovery from damage were investigated. The injection of FSH resulted in no significant differences in the histopathological findings of spermatogenic damage induced by anti-cancer agents or testicular transferrin concentration as compared to those observed without FSH injection. But, in the protocol of the experiments on acceleration of recovery from spermatogenic damage induced by anti-cancer agents, the spermatid index without FSH was 1.02 +/- 0.24, that with FHS 75 IU/kg was 1.50 +/- 0.15, and that with FSH 150 IU/kg was 1.62 +/- 0.39, a significant difference (p < 0.05). Also, the PCNA labeling index and testicular transferrin concentration were significantly different with FSH from those without FSH.

Animals↗