Effects of Exogenous LH or FSH on Endogenous FSH, Progesterone and Estradiol Secretion1

Schwartz, Neena B.; Talley, William L.

doi:10.1095/biolreprod18.5.820

Cited by 36 publications

(8 citation statements)

References 32 publications

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“…On day 5, the serum E 2 concentration was increased in the ketamine-treated rats. This finding is different from those of previous studies [15,16] and shows that these are some differences between pentobarbital and ketamine in the effect on E 2 synthesis. In normal rats, the ovaries secrete predominantly E 2 before ovulation and produce mainly progesterone after ovulation [17].…”

Section: Discussioncontrasting

confidence: 99%

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Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat

Lee

Kim

et al. 2000

Journal of Anesthesia

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Section: Discussioncontrasting

confidence: 99%

“…Serum E 2 concentrations on day 1 were lower than those during proestrus in ovulation-blocked rats [15,16]. In accordance with the reports by Barraclough et al [6] and Uilenbroek et al [8], the concentrations of P 4 and T were decreased in all groups in the present study.…”

Section: Discussionsupporting

confidence: 92%

Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat

Lee

Kim

et al. 2000

Journal of Anesthesia

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“…4) strengthens the interpretation that the secondary surge is necessary and sufficient for follicular recruitment on estrus. It is known-that endogenous or exogenous LH surges will stimulate a secondary increase in FSH (3,19 (3,19). The essential function of the primary FSH surge is obscure because it is known to be redundant to the LH surge for ovulation (3,8) and triggering of the secondary FSH increase (3,19) and unnecessary for follicular recruitment (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The primary surges of LH (and FSH) cause the resumption of oocyte meiosis (21) and ovulation in the mast mature cohort of follicles. Synchronously, the primary LH surge suppresses the secretion from the ovaries of a peptide hormone, folliculostatin, which has been holding tonic levels of FSH in check throughout the cycle (3,11,22). With the decrease in circulating folliculostatin, serum FSH increases before midnight (1-3) and remains increased until the morning of estrus.…”

Section: Methodsmentioning

confidence: 99%

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Blockade of recruitment of ovarian follicles by suppression of the secondary surge of follicle-stimulating hormone with porcine follicular field.

Hoak¹,

Schwartz²

1980

Proc. Natl. Acad. Sci. U.S.A.

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The increased serum concentration of follicle-stimulating hormone (FSH; follitropin) between proestrus and estrus in the rat has been hypothesized to recruit the follicles destined to During the afternoon of the day known as proestrus in the rat estrous cycle the two gonadotropic hormones, luteinizing hormone (LH; lutropin) and follicle-stimulating hormone (FSH; follitropin), surge between 1400 and 2000 hr (1,2). By midnight between proestrus and the next day, estrus, the serum LH level returns to baseline but FSH remains increased throughout the night until 1200 hr on estrus (1-3). This continued secretion of FSH has been called the "secondary FSH surge."Reflecting the marked alterations in serum gonadotropins, between the mornings of proestrus and estrus there is also a discontinuous growth of ovarian follicles into the "pre-Graafian " size class, 390-500 gm in diameter (4, 5). McClintock.and Schwartz (6) first proposed that, although the LH surge terminated the cycle in progress by inducing ovulation, the FSH secretion at proestrus initiated the recruitment of the cohort of follicles that would ovulate in the next cycle.Recently an experimental tool has become available for selectively suppressing serum FSH without altering serum LH or interfering with radioimmunoassay of blood levels of gonadotropin, as does antiserum to gonadotropic hormones (7,8).Porcine follicular fluid (PFF) contains a protein called "folliculostatin" or "ovarian inhibin" which inhibits the secretion of FSH specifically in both intact and ovariectomized female rats (9-13). In fact, Schwartz and Channing (11) have shown that injection of PFF late in proestrus (1545 and 1830 hr), after the primary LH and FSH surges have taken place, specifically suppresses the secondary FSH surge. Moreover, PFF administered earlier on the day of proestrus (1200 hr) suppresses the primary FSH surge without affecting the LH surge; however, after the effect of PFF wears off, the secondary FSH surge occurs (12,13). Thus, by using PFF it is possible to test the hypothesis that either the primary or the secondary FSH surge in proestrus and estrus is necessary for the recruitment of ovarian follicles.In the present study ovarian follicles in 50-,m diameter size classes from 250 to >500gum (preovulatory) were measured in four protocols. In experiment I, ovaries from untreated control rats were removed on the mornings of proestrus and estrus, to establish the timing of the phenomenon of follicular recruitment in our rats showing 4-day estrous cycles. In experiment II, rats were treated with PFF late in proestrus to block the secondary FSH surge (11) and were autopsied on the morning of estrus. In experiment III, rats were treated with PFF early in proestrus, to block the primary FSH surge (12), and were autopsied on the morning of estrus. Follicular recruitment was blocked when the secondary, but not the primary, FSH surge was suppressed. Moreover, in experiment IV, replacement with ovine FSH restored follicular recruitment in a dose-dependent manner.

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Role of Ovarian Inhibin (Folliculostatin) in Regulating FSH Secretion in the Female Rat

Schwartz¹

1982

Intraovarian Control Mechanisms

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Effects of Exogenous LH or FSH on Endogenous FSH, Progesterone and Estradiol Secretion1

Cited by 36 publications

References 32 publications

Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat

Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat

Blockade of recruitment of ovarian follicles by suppression of the secondary surge of follicle-stimulating hormone with porcine follicular field.

Role of Ovarian Inhibin (Folliculostatin) in Regulating FSH Secretion in the Female Rat

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