Delay of the Selective Surge of Follicle-Stimulating Hormone by Bovine Follicular Fluid During the Period of Ovulation Induced by Human Chorionic Gonadotrophin in Dioestrous Rats

Sasamoto, Shigemi; Otani, Tsuyoshi; Shirota, Mariko

doi:10.1677/joe.0.0890205

Cited by 12 publications

(7 citation statements)

References 15 publications

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“…This observation is not consistent with previous reports in cyclic rats, in which it was suggested that the periovulatory FSH surge in 4-or 5-day cyclic rats is responsible for follicular re¬ cruitment for the next oestrous cycle (Schwartz, 1974;Welschen & Dullaart, 1976;Sasamoto et al 1977: Hirshfield & Midgley, 1978aHoak & Schwartz, 1980;Hirshfield & DePaolo, 1981;Sasamoto et al 1981;Mizuno et al 1983). However, the development and maturation of Graafian follicles were observed during late pregnancy and lactation without an FSH surge (Richards & Kersey, 1979;Richards, 1980;Taya & Sasamoto, 1981).…”

Section: Discussioncontrasting

confidence: 99%

“…It is postulated that the prolonged surge of folliclestimulating hormone (FSH) during the periovulatory period plays a major role in the recruitment of fol¬ licles for the next oestrous cycle in the normal cyclic rat (Schwartz, 1974;Welschen & Dullaart, 1976;Sasamoto, Harada & Taya, 1977Hirshfield & Midgley, 1979aJr, Hoak & Schwartz, 1980Sasamoto, Otani & Shirota, 1981). It has recently been suggested that the secondary surge of FSH is responsible for this selection process (Hirshfield & DePaolo, 1981).…”

Section: Introductionmentioning

confidence: 99%

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Initiation of ovarian follicular maturation without a surge of FSH in cyclic rats treated with antiserum to LH-releasing hormone

Matsuzono¹,

Taya²,

Watanabe³

et al. 1986

Journal of Endocrinology

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The relationship between a surge of FSH and the initiation of follicular maturation was examined using rats with a 4-day oestrous cycle. When antiserum against LH-releasing hormone (LHRH-AS) was given at 13.00 h on the day of pro-oestrus (day 0), surges of FSH and LH were blocked. Plasma FSH and LH were maintained at low basal levels without a surge release until the next spontaneous surge occurred on the afternoon of day 4, the predicted day of pro-oestrus. Follicular responsiveness to an injection of human chorionic gonadotrophin (hCG) indicated that preovulatory follicles, present at the time of treatment with LHRH-AS, were capable of ovulating on day 1 but had regressed by day 2. Subsequently, as shown by the ovulatory response to hCG, a new set of follicles had begun to mature by the morning of day 3 without a preceding surge of FSH. Changes in oestradiol-17 beta levels in the plasma throughout the oestrous cycle were the same in rats injected with LHRH-AS or non-immune control serum. The mature follicles in the rats treated with LHRH-AS thus retained the capacity to ovulate after losing their ability to secrete oestrogen. These results suggest that an FSH surge is not essential for initiation of follicular maturation and that basal levels of FSH may be enough to initiate follicular maturation in the absence of newly formed corpora lutea.

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Initiation of ovarian follicular maturation without a surge of FSH in cyclic rats treated with antiserum to LH-releasing hormone

Matsuzono¹,

Taya²,

Watanabe³

et al. 1986

Journal of Endocrinology

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“…Other observations made in this study showed that material present in bFF, but not in rGCCM, suppressed LH secretion (see also Sasamoto, Otani & Shirota, 1981 ). An explanation has not yet been found, but this phenomenon could be a result either of varying sensitivity of the female rat pituitary cells used in the present study, due to cyclic changes in hormonal priming in vivo, or of the presence of other substances, which affect gonadotrophin secretion, in follicular fluid (de Jong et al 1979).…”

Section: Discussionsupporting

confidence: 75%

Inhibin-like activity in media from cultured rat granulosa cells collected throughout the oestrous cycle

Sander¹,

Leeuwen²,

Jong³

1984

Journal of Endocrinology

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Granulosa cells of antral ovarian follicles from adult 5-day cyclic rats were cultured on each day of the cycle. The rat granulosa cell conditioned medium (rGCCM) was harvested and renewed on each day of a 4-day culture period. Inhibin-like activity and progesterone were estimated in rGCCM using an in-vitro bioassay system with dispersed rat anterior pituitary cells and radioimmunoassay respectively. Removal of steroids from rGCCM with dextran-coated charcoal was effective and did not significantly change the inhibin-like activity of the treated samples. On day 1 of culture the inhibin-like activity of rGCCM for each day of the oestrous cycle was 20-90% higher than on days 2, 3 and 4 of culture when low and constant levels were observed. Media collected after culture on days 1 and 2 from pro-oestrous cells contained larger amounts of inhibin-like activity than media collected on the other days of the cycle. On day 1 of culture, rGCCM from pro-oestrous cells contained higher concentrations of progesterone than that from cells collected on the other days of the cycle. On days 2, 3 and 4 progesterone levels in rGCCM were undetectable (less than 320 pmol/l) except in media from pro-oestrous cultures on day 2. Addition of FSH (62 micrograms/l) to granulosa cell cultures in medium with or without 10% fetal calf serum (FCS) did not alter the inhibin-like activity of rGCCM from pro-oestrous cells. The presence of FCS maintained the production of inhibin-like activity since rGCCM from cells cultured without FCS was devoid of FSH-suppressing activity after 3 days of culture.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…The selective release of FSH is inhibited by the injection of charcoal stripped bovine follicular fluid [29], and plasma levels of inhibin decrease as does the selective release of FSH, after 10 IU hCG treatment in diestrous rats [9]. These data indicate that the selective release of FSH during the period of induction of ovulation is brought about by a Table 2.…”

Section: Discussionmentioning

confidence: 81%

Effects of Indomethacin on the Selective Release of Follicle-Stimulating Hormone during the Period of Ovulation in the Rat.

Shirota

Watanabe

Taya

et al. 1998

The Journal of Veterinary Medical Science

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ABSTRACT. To determine whether indomethacin, a potent inhibitor of prostaglandins endoperoxide synthetase, affects the selective folliclestimulating hormone (FSH) surge during the period of ovulation, the compound was administered intravenously (iv), concurrent with 10 IU human chorionic gonadotropin (hCG), to diestrous female rats at 16:00 hr. Indomethacin inhibited the number of ovulations in a dosedependent manner, and treatment with 500 µg indomethacin reduced number of oocytes in the ampullae most effectively without enteric lesions. In the histological observation, oocytes that had began to mature were found not only in unruptured luteinized follicles but also in ovarian interstitium beneath ruptured luteinized follicle. Despite the inhibitory effects of indomethacin on ovulation, peri-ovulatory FSH and progesterone surges occurred in comparable levels and duration to vehicle-treated animals. These results indicate that indomethacininduced inhibition of prostaglandin synthesis does not affect the selective release of FSH during the peri-ovulatory period. [30], and that pretreatment with indomethacin reduces these effects of PGs on hypothalamicpituitary axis [32]. On the other hand, indomethacin decreased peripheral levels of inhibin during the period of eguine chorionic gonadotropin (eCG)-stimulated and -non stimulated folliclular development in immature rats [12][13][14] with an increase of peripheral FSH level [13]. However, these reports do not provide an answer to the question whether indomethacin treatment at the dose level to inhibit ovulation affects the secondary FSH surge which has been observed during the period of ovulation.The present study was undertaken to predict whether indomethacin affects the secondary FSH surge, and effects of indomethacin on the selective release of FSH during the period of induction of ovulation in diestrous rats by hCG [28] were examined by measuring plasma levels of FSH after concurrent injection of hCG and indomethacin at the dose level to inhibit inducing ovulation. Plasma levels of LH and progesterone were also determined to examine effects of the compound on hypothalamic-pituitary axis and luteinization, respectively, and histological changes in the ovary were examined for oocyte maturation and ovulation. The present results provide the evidence that indomethacin at the dose level to inhibit ovulation does not affect the selective release of FSH during the period of ovulation, suggesting that PGS-generated arachidonic acid metabolites might not be involved in the rapid fluctuation of inhibin/ activin biosynthesis during this period. Ovulation is the process by which gametes are supplied for fertilization; in addition, ovulation promotes the ensuing ovulatory cycles unless fertilization has occurred in the rat. Once preovulatory gonadotropin surges occur, mitotic maturation of the oocytes is initiated and is followed by luteinization of the granulosa cells and rupture of folliclular walls in the Graaffian follicle. A new set of follicles, which reach the antral s...

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Delay of the Selective Surge of Follicle-Stimulating Hormone by Bovine Follicular Fluid During the Period of Ovulation Induced by Human Chorionic Gonadotrophin in Dioestrous Rats

Cited by 12 publications

References 15 publications

Initiation of ovarian follicular maturation without a surge of FSH in cyclic rats treated with antiserum to LH-releasing hormone

Initiation of ovarian follicular maturation without a surge of FSH in cyclic rats treated with antiserum to LH-releasing hormone

Inhibin-like activity in media from cultured rat granulosa cells collected throughout the oestrous cycle

Effects of Indomethacin on the Selective Release of Follicle-Stimulating Hormone during the Period of Ovulation in the Rat.

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