Peripheral blood levels of immunoreactive inhibin during pseudopregnancy, pregnancy and lactation in the rat

Taya, Kazuyoshi; Komura, Hisashi; Watanabe, Gen; Sasamoto, Shigemi

doi:10.1677/joe.0.1210545

Cited by 41 publications

(20 citation statements)

References 32 publications

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“…Previous studies (Kishi et al 1995, Ohshima et al 1999) also demonstrated that the changing pattern of plasma concentrations of inhibin corresponded well with the number of healthy large antral follicles during the oestrous cycle. Similar correlations of inhibin and follicular development have also been observed in female rats in the various reproductive stages (Taya et al 1989). In the present study, after ovariectomy but not after hysterectomy or placentectomy, plasma concentrations of inhibin A and inhibin B decreased abruptly.…”

Section: Discussionsupporting

confidence: 89%

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A

Ohshima

Kishi²,

Itoh³

et al. 2002

Journal of Endocrinology

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Numerous antral follicles develop during the second half of pregnancy in the golden hamster. However, mechanisms regulating follicular development during this period are unknown. Because inhibin and activin are related to follicular development, these hormones were studied to gain insight into any potential roles in follicular development. Plasma inhibin A and B suddenly increased from day 8 of pregnancy, reached peak levels on day 10 and gradually declined to term. Plasma activin A gradually increased from day 8 to day 15 of pregnancy, and this was followed by an abrupt decrease at day one of lactation. Ovariectomy on day 12 of pregnancy rapidly reduced plasma inhibin A and B, but not activin A levels.Hysterectomy or placentectomy on day 12 of pregnancy caused an abrupt decrease in the levels of plasma activin A and FSH, but not inhibin A and B at 6 h after surgery. Hysterectomy also induced atresia of large antral follicles at 24 h after surgery. These results indicate that antral follicles are the main source of circulating inhibin A and B, whereas uteri and placentae are the main source of circulating activin A. These results suggest that increased levels of activin A may be involved in folliculogenesis in the ovary during the second half of pregnancy in the golden hamster.

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Section: Discussionsupporting

confidence: 89%

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A

Ohshima

Kishi²,

Itoh³

et al. 2002

Journal of Endocrinology

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“…The results of the present study, together with those of our previous study [22], therefore, suggest that basal levels of LH are essential for follicular maintenance and secretion of inhibins and estradiol-17β during the second half of pregnancy in the golden hamster. Supporting the present study, tonic secretion of LH play an important role in the regulation of follicular development during the various reproductive stages in the rat [9,[23][24][25][26][27][28].…”

Section: Discussionsupporting

confidence: 83%

Roles of Basal Levels of Circulating Luteinizing Hormone on Follicular Maturation in the Pregnant Golden Hamster (Mesocricetus auratus).

Ohshima

Itoh

Kishi

et al. 2002

Journal of Reproduction and Development

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Abstract.To investigate physiological roles of basal levels of circulating LH on follicular development during the second half of pregnancy in golden hamsters, we treated animals with anti-luteinizing hormone (A/LH) or normal horse serum (control serum) at 1100 h on day 12 of pregnancy (day 0 of pregnancy=sperm positive in vaginal smear). Thereafter, changes in plasma concentrations of immunoreactive (ir)-inhibin, estradiol-17β, progesterone and testosterone were determined until 48 h after the treatment; ovaries were also examined immunohistochemically. Furthermore, pregnant golden hamsters were injected with human chorionic gonadotropin (hCG) to determine the effects of immunoneutralization of LH on follicular activity. Plasma concentrations of ir-inhibin and estradiol-17β decreased significantly within 24 h after A/LH treatment, while plasma concentrations of progesterone and testosterone were unchanged. The number of follicles ovulating in response to hCG in the A/LH treated groups (7.0 ± 3.4, n=3) was significantly lower than in the control serum treated group (34.6 ± 4.8, n=5) at 24 h after the treatment. Immunostaining of inhibin α subunit was observed in granulosa cells of healthy and atretic large follicles at 24 h after A/LH treatment, whereas immunopositive reaction of aromatase was not observed in atretic follicles. Positive immunoreaction of 17α-hydroxylase/C17, 20-lyase (CYP17) was observed in theca cells of healthy follicles but not in atretic follicles. These results clearly demonstrate that basal levels of circulating LH are important for maturation of antral follicles and secretion of ir-inhibin and estradiol-17β, but not for progesterone during the second half of pregnancy in the golden hamster. Key words: Follicular maturation, LH, Pregnancy, Hamster (J. Reprod. Dev. 48: [363][364][365][366][367][368][369] 2002) uring pregnancy in the golden hamster, striking changes in the ovary occur, i.e. the corpora lutea of pregnancy become large [1] and the secretion of inhibins, activin A, progesterone

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“…Dev. 43: [279][280][281][282][283][284][285][286][287] 1997) ntral follicles usually exist in the ovary during pseudopregnancy of the rat, although plasma reported previously [4,5]. A specific surge of FSH is not essential for the recruitment and development of a new set of follicles in cyclic rats [6].…”

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confidence: 99%

Roles of the Basal Level of LH and FSH in the Regulation of Follicular Development during Pseudopregnancy in the Rat.

Kishi

Kondoh

Nagamine

et al. 1997

Journal of Reproduction and Development

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Abstract. Present study was conducted to investigate roles of the basal level of FSH and LH in the follicular maturation and maintenance during pseudopregnancy of the rat. Antiserum against luteinizing hormone releasing hormone (LHRH-AS) or charcoal-treated porcine follicular fluid (PFF; a crude inhibin preparation) was given to individual animals on day 5 of pseudopregnancy. Plasma LH and inhibin decreased after treatment with LHRH-AS. Contrarily, plasma FSH increased after LHRH-AS injection. The number of follicles capable of ovulating in response to human chorionic gonadotropin (hCG) in animals given LHRH-AS declined gradually, reached a nedir at 24 h after the treatment, and then returned to control levels during the subsequent 24 h. On the other hand, plasma FSH levels in rats given three injections of 0.5 ml PFF at 6-h intervals, compared to those in control animals, remained significantly lower at nearly all time points during the first 24 h after the initial PFF injection, and thereafter the hormone levels temporarily increased, being significantly elevated above the control value at 30 and 42 h after the initial PFF injection. Only in the rats given intraperitoneal injections of 0.5 ml PFF, compared to the control animals, plasma LH concentrations remained significantly lower at 9 h after the initial PFF injection and those values were significantly higher at 36 h after the initial treatment. The number of follicles capable of ovulating in response to hCG decreased in PFF-treated animals in a dose-dependent-manner. The follicular development in animals given injection of 0.5 ml PFF were virtually or completely inhibited from 12 to 36 h after the initial injection of PFF. Present results clearly indicate that the basal secretion of both LH and FSH are essential for follicular development and maintenance during pseudopregnancy of the rat. These results also suggest that inhibin is a primary factor to suppress FSH secretion in the pseudopregnant rat. Key words: Pseudopregnant rat, Inhibin, Follicles, FSH, LH.(J. Reprod. Dev. 43: [279][280][281][282][283][284][285][286][287] 1997) ntral follicles usually exist in the ovary during pseudopregnancy of the rat, although plasma reported previously [4,5]. A specific surge of FSH is not essential for the recruitment and development of a new set of follicles in cyclic rats [6]. On the other hand, there is a previous study that shows the importance of basal levels of FSH in plasma to cause a normal follicular development and maturation in cyclic rats [7]. It has been known that both LH and FSH are necessary to maintain the activity of growing follicles [8,9]. Administration of LH caused a follicular A concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were suppressed to the basal level [1][2][3]. Plasma concentrations of inhibin and estradiol showed relatively high basal levels during this period as

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Peripheral blood levels of immunoreactive inhibin during pseudopregnancy, pregnancy and lactation in the rat

Cited by 41 publications

References 32 publications

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A

Roles of Basal Levels of Circulating Luteinizing Hormone on Follicular Maturation in the Pregnant Golden Hamster (Mesocricetus auratus).

Roles of the Basal Level of LH and FSH in the Regulation of Follicular Development during Pseudopregnancy in the Rat.

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