Inhibin increases in the ovaries of female rats approaching first ovulation: relationships with follicle growth and serum FSH concentrations

Sander, H. J.; Meijs-Roelofs, H. M. A.; Leeuwen, E. C. M. van; Kramer, P.; Cappellen, Wiggert A. van

doi:10.1677/joe.0.1110159

Cited by 21 publications

(8 citation statements)

References 11 publications

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“…FSH administration also stimulated follicular growth and maturation, and positive staining for inhibin sub units was demonstrated in the granulosa cells of preantral and antral follicles. The result is in accord with the pre vious results that FSH increases inhibin niRNA levels in the hypophvsectomized rat ovary [ 16] and that FSH stim ulates inhibin production by the granulosa cells [5,6,[17][18][19], The intensity of immunostaining was higher in antral granulosa cells than in mural granulosa cells. It is sug gested that antral and mural granulosa cells might re spond differently to FSH.…”

Section: Discussionsupporting

confidence: 89%

Effects of Estrogen, Pituitary Gonadotropins and Prolactin on Immunohistochemical Localization of Inhibin Subunits in the Ovary of Hypophysectomized Female Rats

Kobayashi¹,

Yamoto²,

Minami³

et al. 1992

Horm Res

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Effects of estrogen, pituitary gonadotropins and prolactin on immunohistochemical localization of α- and β_A-subunits in the ovaries of hypophysectomized female rats were investigated. Hypophysectomy resulted in disappearance of immunoreactive inhibin subunits in the ovary. Administration of DES, FSH and LH to hypophysectomized rats provoked growth of follicles, and resulted in positive immunostaining for inhibin subunits in the granulosa cells. In contrast to follicle-stimulating hormone (FSH) and luteinizing hormone (LH), prolactin administration failed to demonstrate positive staining for inhibin subunits in the ovary. The present in vivo results suggest that several hormones which are known to stimulate granulosa cell growth and maturation, such as estrogen, FSH and LH, enhance inhibin subunit production by the overy. The morphologic aspect of inhibin subunit production by the ovary in response to several hormones has been demonstrated in the present study.

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Section: Discussionsupporting

confidence: 89%

Effects of Estrogen, Pituitary Gonadotropins and Prolactin on Immunohistochemical Localization of Inhibin Subunits in the Ovary of Hypophysectomized Female Rats

Kobayashi¹,

Yamoto²,

Minami³

et al. 1992

Horm Res

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“…During this period the increasing content of ovarian inhibin correlates well with the number of large antral follicles present in the ovaries and is associated with declining serum FSH concentrations (Sander, MeijsRoelofs, van Leeuwen et al 1986). During the last 5 days before the day of first ovulation specific changes in the secretion pattern of luteinizing hormone (LH) (Meijs-Roelofs et al 1983) as well as a clear increase in ovarian inhibin content (Sander et al 1986) were found in our rats. In view of these findings, a role for inhibin in the regulation of late prepubertal follicle growth and the numbers of ovulating ova at first oestrus, similar to its role during the adult cycle, may be expected.…”

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confidence: 51%

Initial ovulation rate and follicle population after injection of inhibin-neutralizing antiserum in the late-prepubertal rat

Sander

Meijs-Roelofs²,

Leeuwen³

et al. 1991

Journal of Endocrinology

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In late-prepubertal female rats passive immunoneutralization of endogenous inhibin was achieved by injection of inhibin antiserum. Effects on follicle population, timing of sexual maturation, ovulation rate at first and second oestrus and serum FSH levels were studied.Rats were injected with antiserum, (non-immune) control serum from castrated sheep (castrated serum) or their IgG fractions, or with saline on day 33 or 3 or 2 days (days \ m=-\ 3/ \ m=-\2) before the expected day of first ovulation, day 38\m=.\5\ m=+-\ 0\m=.\2 (n = 70). Blood was collected from different subgroups at 8, 24 and 48 h, and at first and second oestrus after injection. At necropsy, ovaries were histologically prepared for differential counting of follicles (48 h and first oestrus) and counting of corpora lutea (CL; first and second oestrus) as an index of ovulation rate.Results from rats injected with either serum or its IgG fraction were not different, as was the case when rats were injected with either castrated serum or saline.Thus, results from groups treated with antiserum and antiserum IgG were combined and labelled 'antiserum', and the castrated serum, castrated serum IgG and saline-treated groups were combined and labelled 'control'. The activity of inhibin-neutralizing antibodies in the circulation ofantiserum-treated rats was reduced by 43% between 8 h and second oestrus after injection, as determined by the binding of purified bioactive radioiodinated 31 kDa bovine inhibin.After antiserum injection on day 33, more healthy antral follicles (vol. > 100 \ m=x\1 0 5 \ g=m\ m3, diameter > 260 \g=m\m) were present in the ovaries at 48 h (70\m=.\6 vs 54\m=.\4;P < 0\m=.\05) and at first oestrus (73\m=.\1 vs 50\m=.\8; P < 0\m=.\05) if first oestrus was reached within 5 days, but numbers were not different iffirst oestrus was more than 5 days after injection (52\m=.\6vs 50\m=.\8).The number of CL after injection of antiserum on day 33 was increased at first oestrus compared with control (13\m=.\4\ m=+-\ 0\m=.\5, n = 30, vs 10\m=.\0\ m=+-\ 0\m=.\2, n = 40; P<0\m=.\001), an effect that was even more clearly present in antiserum-injected rats ovulating within 5 days (14\m=.\4 \ m=+-\ 0\m=.\7, n = 20; P < 0\m=.\001).Rats injected with antiserum at days \m=-\ 3/ \m=-\2 showed a doubling of ovulation rate at first oestrus when compared with control animals (21\m=.\5 \ m=+-\ 0\m=.\8, n=12, vs 10\m=.\5\ m=+-\ 0\m=.\2, n = 15; P < 0\ m=. \ 001). No differences in the number of CL was seen at second oestrus. Age and body weight on the day of first ovulation were not influenced by antiserum treatment.Serum FSH was significantly (P < 0\m=.\01) increased at 8 h after antiserum injection on either day 33 or on days \m=-\3/\m=-\2 to a level of 250 and 800% of control levels respectively.Thus, injection with inhibin \p=n-\neutralizing antiserum into prepubertal female rats resulted, through an increase in serum FSH concentration 8 h after injection, in the growth of additional numbers of healthy antral follicles. Supranormal ovulation rate occurred if...

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“…The pattern of follicle devel¬ opment leading towards first ovulation and starting at about 8 days before this ovulation (Meijs-Roelofs, Osman & Kramer, 1982) is presumably largely regu¬ lated by the hypothalamo-hypophysial-ovarian feed¬ back system that becomes operative in its fully mature form by this time. In this regulatory system subtle changes in the patterns of LH and FSH secretion Meijs-Roelofs, Kramer & Sander, 1983;Urbanski & Ojeda, 1985) on the one hand, and of ovarian oestradiol and inhibin produc¬ tion on the other (Meijs-Roelofs, Uilenbroek, de Greef et al 1975;Sander, Meijs-Roelofs, van Leeuwen et al 1986) play decisive roles. The infantile and juvenile gonadotrophic situation seems, apart from the necessity of the presence of a basic level (about 200 pg FSH/1 in our study), to be of only mar¬ ginal influence.…”

Section: Discussionmentioning

confidence: 99%

Short- and long-term effects of an LHRH antagonist given during the prepubertal period on follicle dynamics in the rat

Meijs-Roelofs¹,

Cappellen²,

Leeuwen³

et al. 1990

Journal of Endocrinology

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The effects of the suppression of the high gonadotrophin concentrations normally present by the end of the second week of life on ovarian follicle dynamics were studied in immature rats. Gonadotrophins were suppressed by treatment with an LHRH antagonist (LHRH-A; Org. 30276) on days 6, 9, 12 and 15, and the total population of ovarian follicles was studied at 15 and 28 days, on the day of first oestrus and on the day of oestrus at or following 90 and 300 days of age. Primordial follicles were counted and growing follicles were counted and measured. In rats treated with LHRH-A, follicle recruitment into the growing pool was clearly diminished; the number of growing follicles was significantly (P less than 0.01) lower up to the day of first oestrus and the pool of primordial follicles was significantly (P less than 0.05) larger at 15 and 28 days. Ovarian weights were significantly lower in rats treated with LHRH-A until at least 90 days of age. However, on the day of oestrus at or after 90 and 300 days of age, there were no differences in either the pool of primordial follicles or the pool of growing follicles between rats treated with LHRH-A and control rats. There was also no difference between groups in the number of fresh corpora lutea at these ages. It was concluded that the early peak in gonadotrophin concentrations in immature rats causes substantial recruitment of follicles into the growing pool.(ABSTRACT TRUNCATED AT 250 WORDS)

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Inhibin increases in the ovaries of female rats approaching first ovulation: relationships with follicle growth and serum FSH concentrations

Cited by 21 publications

References 11 publications

Effects of Estrogen, Pituitary Gonadotropins and Prolactin on Immunohistochemical Localization of Inhibin Subunits in the Ovary of Hypophysectomized Female Rats

Effects of Estrogen, Pituitary Gonadotropins and Prolactin on Immunohistochemical Localization of Inhibin Subunits in the Ovary of Hypophysectomized Female Rats

Initial ovulation rate and follicle population after injection of inhibin-neutralizing antiserum in the late-prepubertal rat

Short- and long-term effects of an LHRH antagonist given during the prepubertal period on follicle dynamics in the rat

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