Effects of an inhibin-like factor present in bovine and porcine follicular fluid on gonadotrophin levels in ovariectomized rats

Welschen, R.; Hermans, W. P.; Dullaart, J.; Jong, Frank H. de

doi:10.1530/jrf.0.0500129

Cited by 102 publications

(42 citation statements)

References 9 publications

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“…Recently, such an inhibin-like or gonadostatin activity from ovarian follicular fluid has been reported (33)(34)(35)(36)(37)(38). However, stimulatory effects of follicular fluid on the pituitary secretion of gonadotropin have never before been reported.…”

Section: Discussionmentioning

confidence: 99%

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

et al. 1981

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A newly discovered small peptide purified from rat follicular fluid stimulates the pituitary to release FSH and LH in vitro as well as in vivo. Dialysates of crude acid extracts of ovarian follicular tissue and fluid from rats pretreated with PMS gonadotropin stimulate the secretion of both LH and FSH, but not PRL, GH, or TSH, in a pituitary monolayer culture system. This stimulating factor, named gonadocrinin for operational facility, is smaller than 3500 daltons; its biological activity disappears after treatment with trypsin. Gonadocrinin is not recognized by two-antisera binding the decapeptide LRF even though D-Phe2,D-Trp6-LR, an LRF analog antagonist, competitively inhibits the activity of ovarian gonadocrinin. Cultured rat granulosa cells also secret substances with gonadocrinin activity in vitro, indicating that the granulosa cells probably are in vivo the source of gonadocrinin. A crude preparation of gonadocrinin given iv to rats on the second day of diestrus induced secretion of LH comparable to that produced by a 250-ng LRF injection. Gonadocrinin has chemical characteristics different from those of LRF. When purified gonadocrinin or LRF was applied to an identical isocratic high pressure liquid chromatography system, LRF was eluted at a position different from that of gonadocrinin, indicating that, chemically, gonadocrinin is not identical to the hypothalamic decapeptide, LRF.

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Section: Discussionmentioning

confidence: 99%

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

et al. 1981

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“…Steroid free bovine (de Jong, Welschen, Hermans, Smith & van der Molen, 1978), equine (Miller, Wesson & Ginther, 1979), human (Chappel, Holt & Spies, 1980), monkey (Channing, Anderson & Hodgen, 1980) and porcine (de Paolo, Wise, Anderson, Barraclough & Channing, 1979b;Schänder, Anderson, Barraclough & Channing, 1980) (1978) indicated that granulosa cells are the probable source of this follicular inhibin, while studies of the rat (de Paolo, Shander, Wise, Barraclough & Channing, 1979a) and monkey (Channing et ai, 1980) have shown that inhibin is secreted into the ovarian vein, thus strengthening the concept that ovarian inhibin may be physiologically important in the regulation of FSH secretion. Inhibin activity in follicular fluid is related to follicle size (Welschen, Hermans, Dullart & de Jong, 1977) and ovarian inhibin production changes throughout the oestrous/menstrual cycle (de Paolo et ai, 1979a;Chappel et ai, 1980). However, there is little information about the regulation of ovarian inhibin production.…”

Section: Introductionmentioning

confidence: 99%

Regulation of inhibin production by bovine ovarian cells in vitro

Henderson¹,

Franchimont²

1981

Reproduction

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Summary. The regulation of ovarian inhibin production was investigated using a rat pituitary cell culture system as a bioassay for inhibin activity. Bovine follicular granulosa cells produced inhibin in vitro provided that the culture medium contained serum. The stimulatory factor(s) present in serum is unlikely to be gonagotrophins, because bovine LH and/or FSH failed to stimulate inhibin production when added to medium devoid of serum.

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“…In addition, rather that regressing, the dominant follicle had an extended lifespan. Thus, the suppressive effect of inhibin and other follicular products that would be produced by the persistent follicle may account for the unchanged FSH levels reported herein [115,155,168,[176][177][178].…”

Section: Discussionmentioning

confidence: 79%

Effects of a non-steroidal aromatase inhibitor on ovarian function in cattle

Yapura

Mapletoft

Singh

et al. 2012

Reprod. Fertil. Dev.

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Two studies were designed to characterize the effects of a non-steroidal aromatase inhibitor, letrozole, on ovarian function in cattle. The specific objective was to test the hypothesis that letrozole will arrest dominant follicle growth resulting in emergence of a new follicular wave at a predictable interval post-treatment. In a first experiment, postpubertal beef heifers were assigned randomly to four treatment groups and given phosphate-buffered saline (controls; n=10), or letrozole at a dose of 500 (n=9), 250 (n=10), or 125 (n=10) µg/kg intravenously 4 days after follicular ablation (~2.5 days after wave emergence). In a second study, postpubertal beef heifers were assigned randomly to four treatment groups. One group received no treatment (control; n=17) and the other groups (n=9-10) were given 85 µg/kg of letrozole per day (250 µg/kg total dose), from Days 1 to 3, Days 3 to 5, or Days 5 to 7 (Day 0 = pre-treatment ovulation,) corresponding to the periods before, during and after selection of the dominant follicle, respectively. Follicular dynamics were monitored ultrasonically and blood samples were collected for endocrine assays. Follicle diameter profiles and plasma LH, FSH, and estradiol concentrations were analyzed. Additionally, during the second trial, CL diameter profiles and plasma progesterone concentrations were measured. In both studies, the diameter profile of the dominant follicle was larger in heifers treated with letrozole than in control heifers (P<0.05) and the intervals to new wave emergence and onset of regression of the extant dominant follicle were longer (P<0.05) in heifers treated with letrozole than in controls, regardless of the dose (high, medium, or low; single vs multiple) and the stage of the follicle wave in which treatments were initiated. Furthermore, during the second experiment, the mean CL diameter was larger in letrozole-treated heifers, although there were no differences in plasma progesterone iii concentrations between treated and control animals. The effects on dominant follicle and CL diameter profiles appeared to be the result of the significantly increased plasma LH concentrations observed in letrozole-treated animals during both treatment approaches (single vs multiple dose). Incomplete and inconsistent inhibition of estradiol production and the lack of a surge on FSH observed in both experiments may be a result of insufficient circulating levels of letrozole during the treatment period. In summary, a single or multiple dose of letrozole did not induce regression of the extant dominant follicle, nor did it directly affect FSH release.Conversely, letrozole extended the lifespan of the dominant follicle, in association with increased endogenous levels of LH, thereby delaying the next FSH surge and subsequent follicular wave emergence. Results suggest that letrozole has potential as a non-steroidal method for controlling ovarian function in cattle, but further studies are warranted to clarify dosage and timing of treatment to predictably affect follicular wa...

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Effects of an inhibin-like factor present in bovine and porcine follicular fluid on gonadotrophin levels in ovariectomized rats

Cited by 102 publications

References 9 publications

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

Gonadocrinins: Peptides in Ovarian Follicular Fluid Stimulating the Secretion of Pituitary Gonadotropins*

Regulation of inhibin production by bovine ovarian cells in vitro

Effects of a non-steroidal aromatase inhibitor on ovarian function in cattle

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