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PubMed1985

The ontogeny of hypothalamic pituitary function in the pig. I. Pituitary LH and FSH in the fetus and neonate.

Pituitaries were collected from fetal and postnatal pigs from day 55 p.c. until 6 weeks after birth at closely spaced intervals. LH and FSH in individual pituitaries were quantified by both homologous RIA and homologous RRA. No significant difference was found between results obtained by RIA and RRA. Both LH and FSH are first detected by RIA and RRA in the porcine fetal pituitary at 75 days p.c. Thereafter both LH and FSH pituitary content rises until term. LH pituitary concentration in both male and female fetuses and FSH pituitary concentration in males exhibit a peak just before birth. FSH pituitary concentration in females rises until birth and thereafter remains elevated. A statistically significant sex difference was found postnatally with regard to FSH content and concentration but not for LH.

Animals↗
PubMed1987

Inhibition by phorbol esters and other tumor promoters of the response of the Sertoli cell to FSH: evidence for dual site of action.

Several tumor promoters exert their effects by activating a Ca2+-phospholipid-dependent protein kinase (protein kinase C). To study the role of this protein kinase in the regulation of Sertoli cell function, we have evaluated the effect of phorbol esters, mezerein, and teleocidin on the response of the Sertoli cell to FSH. Cells were treated for different time intervals with the tumor promoters, and cell response was measured by stimulating the cell with FSH. 12-O-Tetradecanoylphorbol 13-acetate (TPA) had no significant effect on basal cAMP production but markedly inhibited the cAMP response to FSH. Significant inhibition of cAMP accumulation was observed after 15 min treatment with 100 nM TPA, and maximal inhibition developed within 1 h. The decrease in cAMP accumulation was dependent on the dose of phorbol ester used, with an estimated ED50 of 10-20 nM TPA. In a manner similar to TPA, mezerein and teleocidin also inhibited the cAMP response of the Sertoli cell, while the phorbol ester 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD), inactive as a tumor promoter and unable to stimulate protein kinase C activity, was devoid of effect. The promoters that inhibited cAMP response also inhibited the FSH-stimulated androgen aromatization. The dose of TPA producing half-maximal inhibition of estrogen accumulation was again 10-20 nM TPA, mezerein, and teleocidin inhibited estrogen accumulation whether FSH, forskolin or cholera toxin was used to stimulate the Sertoli cell. In contrast, only FSH-dependent cAMP accumulation was inhibited by the tumor promoters, while forskolin and cholera toxin stimulations were not affected. These data suggest that tumor promoters which activate protein kinase C act at two sites of the Sertoli cell response. They alter receptor-mediated signal transduction across the membrane and affect steroidogenesis at a site distal to cAMP accumulation.

Androstenedione↗
PubMed1988

Effects of FSH and IGF-I on immature rat Sertoli cells: inhibin alpha- and beta-subunit mRNA levels and inhibin secretion.

Effects of follicle-stimulating hormone (FSH) and insulin-like growth factor-I (IGF-I) on inhibin production by cultured Sertoli cells from 21- to 23-day-old rats were studied. The expression of inhibin alpha- and beta-subunit mRNAs, and inhibin immunoreactivity and in vitro bioactivity were estimated. Using a cDNA probe corresponding to the alpha-subunit of bovine inhibin, specific hybridization with a 1.5-1.7 kilobase (kb)mRNA species was observed. Addition of FSH to the cultured Sertoli cells for 24 h markedly increased the level of this mRNA in a dose-dependent way. IGF-I had no effect on the intensity of the hybridization. Using a cDNA probe corresponding to the beta B-subunit of human inhibin, 3.5 and 4.2 kb mRNA species were detected. FSH and IGF-I had no effect on the hybridization signal. No hybridization was observed with a cDNA probe corresponding to the beta A bovine inhibin subunit. Inhibin activity was detected in cells and medium by immunoassay, and in the medium by in vitro bioassay. FSH stimulated both immunoreactivity and in vitro bioactivity, whereas IGF-I had no effect at all. The present effect of FSH on inhibin alpha-subunit mRNA expression in cultured Sertoli cells indicates that regulation of inhibin production by FSH includes an effect at the transcriptional level. However, this does not exclude additional translational and posttranslational effects.

Animals↗
PubMed1995

Inhibition of proteoglycan synthesis induces an increase in follicle stimulating hormone (FSH)-stimulated estradiol production by immature rat Sertoli cells.

In order to define the possible involvement of proteoglycans (PG) in the regulation of Sertoli cell functions, we have examined the effect of para-nitrophenyl-beta-D-xyloside (PNPX), a specific inhibitor of PG synthesis, on follicle stimulating hormone (FSH)-dependent estradiol production by immature rat Sertoli cells. Addition of PNPX to the culture medium induced a dose-dependent inhibition of 35S-labeled PG synthesis in Sertoli cells both in the medium and the cell layer. Simultaneously there was a drastic increase in 35S-labeled secreted glycosaminoglycans. By 1 mM PNPX, syntheses of chondroitin sulfate proteoglycans released into culture medium and of heparan sulfate proteoglycans associated with the cell layer were 35% of values from untreated cells. Simultaneously, PNPX induced a twofold (mean of seven experiments, range 17-250%) enhancement of FSH (100 ng/ml)-stimulated estradiol production. In each individual experiment, there was an inverse relationship between the amplitude of PNPX-induced increase in FSH responsiveness and the FSH capability to stimulate basal estradiol production in cultured rat Sertoli cells. The effect of PNPX on FSH-stimulated aromatase activity was not mimicked by para-nitrophenyl-beta-D-galactoside, a structural analog of PNPX that has no effect on PG synthesis. The (Bu)2cAMP-stimulated estradiol synthesis was not modified in the presence of PNPX. Moreover, PNPX enhancement of FSH-stimulated estradiol synthesis disappeared when Sertoli cells were cultured in the presence of 1-methyl-3-isobutylxanthine, an inhibitor of phosphodiesterase activity. These findings suggest that inhibition of PG synthesis under PNPX conditions did not affect signal transduction steps distal to cAMP but rather decreased the phosphodiesterase activity in Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗
PubMed1982

Ipsilateral hypothalamic deafferentation blocks the increase in serum FSH following hemi-castration.

In two experiments hypothalamic hemi-islands or sham surgeries were produced on the right side of prepubertal male rats with an extrudable Halàsz-type knife (1.5 mm radius). Animals were then sham castrated or else hemi-castrated on the contralateral or ipsilateral side with respect to brain surgery. Eight or 21 days later, hemi-castrated rats given sham knife cuts showed a significant increase in serum FSH, relative to sham animals with intact testes. Also, animals given hypothalamic hemi-islands and hemi-castrated on the contralateral side showed a significant increase in serum FSH comparable to that seen in hemi-castrated rats with sham brain surgeries. However, hypothalamic hemi-island rats which were hemi-castrated on the ipsilateral side failed to show an increase in serum FSH and were similar to sham operated controls with both gonads. Serum LH levels were comparable among all groups, verifying a clear dissociation between LH and FSH secretion associated with hemi-castration in prepubertal males. In addition, the differences between contralateral and ipsilateral hemi-castrated animals with identical unilateral brain surgeries strongly suggest that FSH release is, in part, under direct neural control. However, in a third experiment, differences in FSH release between ipsi- and contralateral hemi-castrated rats were not found in animals with hypothalamic hemi-islands on the left side of the brain. Thus the hypothalamus may be asymmetrically involved in various components of neuroendocrine control.

Afferent Pathways↗
PubMed1988

Measurement of the amount of mRNA for gonadotropins during an estradiol-induced preovulatory-like surge of LH and FSH in ovariectomized ewes.

The amount of messenger RNA (mRNA) for luteinizing hormone beta-subunit (LH beta), follicle-stimulating hormone beta-subunit (FSH beta) and alpha-subunit was measured during estradiol-17 beta (E) positive feedback in ovariectomized (OVX) ewes. During the anestrous season, OVX ewes were given an i.m. injection of E (25 micrograms: n = 5) or oil (control; n = 4) and hourly blood samples were collected for 16 hr. After blood collection, ewes were killed and anterior pituitary glands were removed for analysis of hormone and mRNA content. Preovulatory-like increases in serum concentrations of LH and FSH were measured in E-treated OVX ewes. In two E-treated OVX ewes the serum concentrations of LH and FSH were still increasing, whereas in the remaining three E-treated OVX ewes, serum concentrations of LH were on the decreasing portion of the E-induced preovulatory-like surge. Pituitary content of LH was lower (P less than .10) in E-treated OVX ewes when serum concentrations of LH were decreasing than that measured in control ewes or E-treated OVX ewes in which serum concentrations were still increasing. Pituitary content of FSH and prolactin were similar (P greater than .05) among all groups. The amount of mRNA for LH beta-subunit was similar (P greater than .05) in ewes in which serum concentrations of LH were increasing and in control ewes, but was lower (P less than .05) in ewes with decreasing levels of LH. The amount of mRNA for FSH beta-subunit was lower (P less than .05) in all E-treated OVX ewes (independent of whether serum concentrations of FSH were increasing or decreasing) than that measured in control ewes. There was no difference (P greater than .05) in the amount of mRNA for alpha-subunit among any groups. Thus, amounts of mRNA for the beta-subunits of gonadotropins are reduced, while amounts of mRNA for alpha-subunit are unchanged during estradiol positive feedback in OVX ewes.

Anestrus↗
PubMed1991

Relationships among LH, FSH and prolactin secretion, storage and response to secretagogue and hypothalamic GnRH content in ovariectomized pony mares administered testosterone, dihydrotestosterone, estradiol, progesterone, dexamethasone or follicular fluid.

Thirty-five ovariectomized pony mares were used to study the relationships among luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) concentrations in blood (secretion), in pituitary (storage) and in blood after secretagogue administration, as well as the content of gonadotropin releasing hormone (GnRH) in hypothalamic areas, under various conditions of steroidal and nonsteroidal treatment. Five mares each were treated daily for 21 d with vegetable shortening (controls), testosterone (T; 150 micrograms/kg of body weight, BW), dihydrotestosterone (DHT; 150 micrograms/kg BW), estradiol (E2; 35 micrograms/kg BW), progesterone (P4; 500 micrograms/kg BW), dexamethasone (DEX; 125 micrograms/kg BW) or charcoal-stripped equine follicular fluid (FF; 10 ml). Secretagogue injections (GnRH and thyrotropin releasing hormone, TRH, at 1 and 4 micrograms/kg of BW, respectively) were given one d prior to treatment and again after 15 d of treatment. Relative to controls, treatment with T, DHT and DEX reduced (P less than .05) LH secretion, storage and response to exogenous GnRH, whereas treatment with E2 increased (P less than .05) these same characteristics. Treatment with P4 reduced (P less than .05) only LH secretion. Treatment with T, DHT, E2 and DEX reduced (P less than .05) FSH secretion, whereas treatment with P4 increased (P less than .05) it and FF had no effect (P greater than .1). All treatments increased (P less than .05) FSH storage, whereas only treatment with T and DHT increased (P less than .05) the FSH response to exogenous GnRH. Other than a brief increase (P less than .05) in PRL secretion in mares treated with E2, secretion of PRL did not differ (P greater than .1) among groups. Only treatment with E2 increased (P less than .01) PRL storage, yet treatment with T or DHT (but not E2) increased (P less than .05) the PRL response to exogenous TRH. Content of GnRH in the body and pre-optic area of the hypothalamus was not affected (P greater than .1) by treatment, whereas treatment with T, E2 and DEX increased (P less than .1) GnRH content in the median eminence. For LH, secretion, storage and response to exogenous GnRH were all highly correlated (r greater than or equal to .77; P less than .01). For FSH, only storage and response to exogenous GnRH were related (r = .62; P less than .01). PRL characteristics were not significantly related to one another. Moreover, the amount of GnRH in the median eminence was not related (P greater than .1) to any LH or FSH characteristic.

Animals↗
PubMed1991

Culture of bovine granulosa cells in a chemically defined serum-free medium: the effect of insulin and fibronectin on the response to FSH.

Granulosa cells from fully differentiated bovine follicles were cultured in serum-free medium for 4 days. At the end of culture, the number of viable cells was low (10-15% of cells plated on day one) and only progesterone secretion responded to FSH. Insulin increased the number of viable cells at the end of culture (ED50 # 70 ng/ml) and stimulated progesterone secretion (ED50 # 50 ng/ml); the secretion of oestradiol-17 beta over basal value was evident only for concentrations of 1000 and 10,000 ng/ml. FSH acted synergistically with insulin to modify steroid secretion. In the presence of 50 ng/ml of insulin, dose-response studies indicated that secretion of progesterone was maximal at 10 ng/ml of FSH and plateaud thereafter, while oestradiol output peaked at 2 ng/ml of FSH, decreasing at higher concentrations. When cells were seeded in wells precoated with fibronectin, a comparison with cells cultured on plastic showed an increase (30-40%) in the number of viable cells at the end of culture and in oestradiol secretion but a decrease in progesterone output. These results indicate that granulosa cells from large bovine follicles, cultured in a serum-free medium containing insulin, maintain their steroidogenic potency for at least 4 days. Moreover, they show that oestradiol and progesterone synthesis are differentially sensitive to FSH concentrations and that fibronectin increases oestradiol secretion in response to FSH.

Animals↗
PubMed2004

Plasma inhibin A determination at start superovulatory FSH treatments is predictive for embryo outcome in goats.

To test whether inhibin A assays can be used for the prediction of yields in embryo programmes in goats, 50 does were treated with 45 mg FGA sponges (Chronogest) for 16 days plus a single dose of 100 microg i.m. cloprostenol on Day 14, just before the start of administration of eight doses of 1.25 ml of Ovagen twice daily for 4 days. At first FSH injection, the number and size of all follicles > or =2 mm was assessed by transrectal ultrasound and plasma inhibin A levels were measured by specific dimeric assay. There was a positive correlation between number of follicles > or =6 mm (8.8 +/- 0.5) and inhibin A levels at first FSH dose (193.2 +/- 14.5 pg/ml, P<0.05). The mean number of corpora lutea on Day 7 after sponge removal was related to the total number of follicles with a diameter of 2-6 mm at the onset of the FSH treatment (15.3 +/- 0.7, P<0.05). The total number of embryos recovered was related to the number of follicles with 4-6 mm in size (6.2 +/- 0.5, P<0.05) and to the inhibin A levels at first FSH dose (P<0.05). These results suggest that follicles > or =4 mm are the source of inhibin prior to FSH stimulation and are the main source of oocytes resulting in the number of viable embryos recovered after a superovulatory treatment. Hence, the response to superovulatory treatments in goats in terms of the number of embryos can be predicted from either the population of follicles determined by ultrasound or the plasma inhibin A levels at start of the superovulatory FSH treatment.

Animals↗
PubMed2004

Preoperative serum levels of follicle stimulating hormone (FSH) and prognosis in invasive breast cancer.

AIMS: We investigated the association between preoperative serum levels of follicle stimulating hormone (FSH) and the prognosis in women with invasive breast cancer. METHODS: Serum levels of FSH were measured in 182 premenopausal and 581 peri- or postmenopausal women with invasive breast cancer. They were followed for a mean time of 84 months. The study endpoint was death from breast cancer (182 events). Analyses were stratified on menopausal status. RESULTS: None of the estimates showed a statistically significant result. In both pre- and postmenopausal women there was a nominally higher probability of survival with a higher FSH level. Point estimates in multivariate analysis incorporating age, tumour diameter, axillary lymph status, estrogen and progesterone receptor content and year of treatment indicated a stronger association with FSH levels in premenopausal than postmenopausal women (relative hazard 0.63 or 0.85, respectively in the highest compared with the lowest quartile). CONCLUSION: We did not find any statistically significant association between preoperative serum level of FSH and prognosis. Today, FSH is not a clinical target for intervention or a clinically useful prognostic factor and the results of clinical studies up to date can only be used for motivation of further experimental laboratory research.

Adult↗
PubMed2006

[Identification of the intercycle FSH signal in urine samples (uFSH)].

OBJECTIVE: The intercycle FSH signal that initiates follicular recruitment and marks the functional onset of the menstrual cycle is of small amplitude and while it commonly occurs on cycle day 3, this often varies. Hence, its identification and measurement in serum (sFSH) requires serial daily samplings. We attempted to determine whether urine measurements of FSH (uFSH) could offer a non-invasive alternative, using a model where the intercycle FSH signal is controlled by timely use of exogenous E2. PATIENTS AND METHODS: Pilot prospective trial in 21 infertile women having received E2, from day 25 of the previous cycle until the 1st Friday after menses. Blood and first void urine samples were collected, starting on the last day of E2 (baseline) for assessing FSH and creatinin. A sonogram was performed for identification of maturing follicles (>12 mm). RESULTS: uFSH and uFSH/Cr showed good correlation with sFSH (R = 0.52 and 0.63, P < 0.0001 and P < 0.0001, respectively). In 15/21 patients who had an intercycle sFSH elevation, this was confirmed by uFSH elevation, both occurring within 2-4 days after stopping E2. In all these women, the sonogram showed evidence of impending ovulation. The amplitude of the uFSH signal was on average 3 times higher than its sFSH counterpart. In 6/21 women, no intercycle FSH elevation was detected and no ovulation occurred. DISCUSSION AND CONCLUSION: Our results show that the intercycle FSH signal can easily be identified and measured in urine. This novel approach permits more precise assessments of ovarian physiology than with blood measurements.

Adult↗
PubMed2006

Carbohydrate complexity and proportions of serum FSH isoforms in the male: lectin-based studies.

FSH is synthesized and secreted in multiple molecular forms with different oligosaccharide structures which are needed for full expression of biological activity. GnRH and sex steroids modulate oligosaccharide structure and composition. In the present study we have assessed the carbohydrate complexity and proportion of circulating FSH isoforms during puberty, aging and after androgen administration to pubertal anorchid boys. Preparative isoelectrofocusing and lectin chromatography were used to isolate FSH isoforms on the basis of charge and internal carbohydrate complexity. Differences in sialic acid content and a progressive increase of isoforms bearing highly branched oligosaccharides were found during puberty. Less acidic, more bioactive FSH isoforms, secreted at mid-puberty may modulate important maturational events in the Sertoli cell population. Androgen administration to pubertal anorchid boys favoured the secretion of this type of isoforms. In adult men, the predominance of FSH isoforms bearing complex type oligosaccharides remained unchanged until very advanced age. These results show that the predominance of FSH isoforms bearing fully processed oligosaccharides in circulation may contribute to the development and maintenance of seminiferous epithelium function in men.

Adolescent↗
PubMed2004

Influences of FSH and EGF on primordial follicles during in vitro culture of caprine ovarian cortical tissue.

Factors that control the onset of folliculogenesis are critical to female gamete production, but poorly understood. The aim of the present study was to investigate the effects of FSH and EGF on the activation and growth of goat primordial follicles in vitro. To this end, pieces of goat ovarian cortex were cultured in vitro for 1, 3 or 5 days, at 39 degrees C in an atmosphere containing 5% CO(2), in minimum essential medium supplemented with insulin, transferrin, selenium, pyruvate, glutamine, hypoxanthine, BSA, penicillin, streptomycin and fungizone and with or without FSH (100 ng/ml) and/or EGF (100 ng/ml). At the end of the culture periods, the relative proportions of primordial, intermediate, primary and secondary follicles were calculated and compared with those in non-cultured tissue. In addition, mitotic activity of granulosa cells was studied by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In brief, it was found that goat primordial follicles activate spontaneously during culture in vitro and, while neither FSH nor EGF affected the proportion of primordial follicles that entered the growth phase, both stimulated an increase in oocyte and follicle diameter, especially in intermediate and primary follicles cultured for 5 days. On the other hand, there was no significant effect of culture or either growth factor on the proportion of PCNA-stained growing follicles. Contrary to expectations, neither FSH nor EGF affected follicle viability or integrity during culture, since the percentages of intact follicles did not differ between control, FSH and/or EGF containing medium. In conclusion, this study demonstrated that goat primordial follicles activate spontaneously in vitro, and that both FSH and EGF stimulate an increase in follicle size by promoting oocyte growth.

Animals↗
PubMed2005

How the FSH/LH ratio and dose numbers in the p-FSH administration treatment regimen, and insemination schedule affect superovulatory response in ewes.

We wished to evaluate the effects of FSH/LH ratio and number of doses of p-FSH during a superovulatory treatment on ovulation rate and embryo production (Experiment I). In Experiment II, we studied the efficacy of fertilization after various insemination schedules in superovulated donors. In Experiment I estrus was synchronized in 40 ewes (FGA, for 9 days plus PGF2alpha on Day 7) and the ewes were randomly assigned to four treatment groups as follows (n = 10 ewes each): Group A: four p-FSH doses with the FSH/LH ratio held constant (1.6); Group B: four p-FSH doses with the FSH/LH ratio decreasing (FSH/LH 1.6-1.0-0.6-0.3); Group C: eight p-FSH doses with the FSH/LH ratio held constant (1.6); Group D: eight p-FSH doses and FSH/LH ratio decreasing (1.6-1.6, 1.0-1.0, 0.6-0.6, 0.3-0.3). p-FSH administrations were performed twice daily 12 h apart. The ewes were mated at the onset of estrus and again after 12 and 24 h; then, one ram per four ewes was maintained with the ewes for two additional days. Ovarian response and embryo production were assessed on Day 7 after estrus. Experiment II. Three groups (n = 10 each) of superovulated ewes were inseminated as follows: Group M: mated at onset of estrus; Group AI: artificial insemination 30 h after onset of estrus; M + AI) mating at onset of estrus and intrauterine AI performed 30 h from estrus with fresh semen. Results of Experiment I showed that treatment (D) improved (P < 0.05) ovulatory response in comparison to Groups (C) and (A). The fertilization rate was lower (P < 0.01) in Group D) than Group (A). Also the proportion of transferable embryos was lower in Group (D) in comparison to all the other treatments (P < 0.01). Group A gave the best production of embryos (7.3/ewe; 89.0% transferable). In Experiment II, combined mating plus AI improved fertilization rate (80.3%) compared to both mating (P < 0.01) and AI (P < 0.02) alone.

Animals↗
PubMed2005

FSH and LH plasma levels in bitches with differences in risk for urinary incontinence.

To determine whether the height of the plasma gonadotropin levels after spaying is associated with urinary incontinence, the concentrations of plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined once in 191 intact and 308 spayed bitches. The bitches were grouped according to their risk for urinary incontinence and the medians of their respective gonadotropin levels were compared. For intact anestrous bitches, the FSH- and LH-plasma concentrations were 5.2 (4, 8) ng/mL (median (Q1, Q3)) and 0.5 (0.5-0.5) ng/mL, respectively. In the first year after spaying, the gonadotropin concentrations rose significantly, then stabilised at a level around 10 times those of intact bitches (FSH 62.5 (44, 91) ng/mL; LH 6.1(4, 11) ng/mL). The plasma gonadotropin concentrations of long-term spayed (>12 months) continent bitches (n=209) were higher (FSH 66.8 (46, 104) ng/mL; LH 6.5 (4, 11) ng/mL) than in spayed incontinent bitches (n=60) (FSH 51.5 (38, 74) ng/mL; LH 5.5 (3, 8) ng/mL), the latter also had a higher body weight. Multiple regression analysis showed that the FSH-plasma concentration and not the body weight was decisive for the occurrence of urinary incontinence. The results of this study suggest that levels of gonadotropins are associated, directly or indirectly in the pathophysiology of urinary incontinence after spaying.

Animals↗
PubMed2006

Ovarian and endocrine responses to prostaglandin F2alpha (PGF2alpha) given at the expected time of the endogenous FSH peak at mid-cycle in ewes.

In the ewe, a rise in circulating concentrations of FSH preceding follicular wave emergence begins in the presence of growing follicles from a previous wave. We hypothesized that prostaglandin F(2alpha) (PGF(2alpha)) given at the time of an endogenous FSH peak in cyclic ewes would result in synchronous ovulation of follicles from two consecutive waves, increasing ovulation rate. Twelve Western White Face (WWF) ewes received a single i.m. injection of PGF(2alpha) (15 mg/ewe) at the expected time of a peak in FSH secretion, from Days 9 to 12 after ovulation. The mean ovulation rate after PGF(2alpha) treatment (2.3+/-0.3) did not differ (P>0.05) from the pre-treatment ovulation rate (1.7+/-0.1). Five ewes ovulated follicles from follicular waves emerging before and after PGF(2alpha) injection (3.0+/-0.6 ovulations/ewe) and seven ewes ovulated follicles only from a wave(s) emerging before PGF(2alpha) treatment (2.0+/-0.3 ovulations/ewe; P>0.05). The mean interval from PGF(2alpha) to emergence of the next follicular wave (1.0+/-0.4 and 4.0+/-0.0 d, respectively; P<0.001) and the interval from PGF(2alpha) treatment to the next FSH peak (0 and 3.5+/-0.4d, respectively; P<0.05) differed between the two groups. Six ewes ovulated after the onset of behavioral estrus, with a mean ovulation rate of 1.7+/-0.2, and six ewes ovulated both before and after the onset of estrus (3.0+/-0.5 ovulations/ewe; P<0.05). None of the ovulations that occurred before estrus resulted in corpora lutea (CL) with a full life span. At 24h before ovulation, follicles ovulating before or after the onset of estrus differed in size (4.1+/-0.3 or 5.5+/-0.4mm, respectively; P<0.05) and had distinctive echotextural characteristics. In conclusion, the administration of PGF(2alpha) at the expected time of an FSH peak at mid-cycle in ewes may alter the endogenous rhythm of FSH secretion and was not consistently followed by ovulation of follicles from two follicular waves. In non-prolific WWF ewes, PGF(2alpha)-induced luteolysis disrupted the normal distribution of the source of ovulatory follicles and may be associated with untimely follicular rupture and luteal inadequacy.

Animals↗
PubMed2006

Molecular cloning of follicle-stimulating hormone (FSH)-beta subunit cDNA from duck pituitary.

We have cloned FSH-beta cDNA from duck pituitary gland by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) methods. The cloned duck FSH-beta cDNA contains 1909-bp nucleotides including 396-bp of open-reading frame and 1491-bp of 3'-untranslational region. The open-reading frame encodes a 131-amino acid protein with a putative 20-amino acid signal peptide and a putative 111-amino acid mature protein. The deduced amino acid sequence shows a remarkable similarity (94-98%) to those of other avian FSH-beta subunits; while it exhibits lower similarities with those of turtles (82-84%), mammals (63-71%), and amphibians (53-57%). The structural model analysis of duck FSH suggests that the cysteine-knot and beta-strands for maintaining the specific structural frame, and the "seat-belt" loop for specific binding to FSH receptor have been conserved in tetrapodian FSH-betas.

Amino Acid Sequence↗
PubMed2002

Dopamine D2 receptors and secretion of FSH and LH: role of sexual steroids on the pituitary of the female rainbow trout.

The role of sexual steroids in the modulation of a dopaminergic inhibitory tone on FSH and LH release was studied in the rainbow trout. The experiments were performed on previtellogenic trout, implanted or not with estradiol (E(2)), and vitellogenic trout. E(2) implant increased the circulating levels of LH and decreased the circulating levels of FSH in previtellogenic fish. The catecholamine inhibitor alphaMPT increased the circulating levels of LH, implanted or not with E(2). AlphaMPT increased circulating levels of LH in vitellogenic fish. This increase could be prevented by the dopaminergic agonist bromocryptine. The dopaminergic drugs had no effect on the circulating levels of FSH in all groups. E(2) decreased mRNA levels of sGnRH1 and sGnRH2 in the telencephalon of previtellogenic fish. The dopaminergic treatments had no effect on mRNA levels of both forms of sGnRH in previtellogenic and vitellogenic fish. Primary cultures of pituitary cells were primed for three days with steroids (E(2) or 17alpha-hydroxy, 20beta-dihydroprogesterone (17alpha20betaP)) before treatment with increasing doses of bromocryptine, associated or not with sGnRH. E(2), but not 17alpha20betaP, potentiated the sGnRH-induced release of LH. Bromocryptine induced a slight dose-dependent decrease of sGnRH-induced release of LH. This decrease was potentiated by 17alpha20betaP. E(2) and 17alpha20betaP had no effect on the release of FSH, but bromocryptine decreased the 10(-8)M sGnRH-induced release of FSH. In conclusion, the development of the dopaminergic inhibitory tone on gonadotropin release, at the onset of vitellogenesis, requires factors other than estradiol. E(2) should contribute in part to decrease the release of FSH. At the end of the reproductive cycle, 17alpha20betaP should reinforce the dopaminergic inhibitory tone.

Animals↗