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, Ken-ichi; Kishi, Hisashi; Itoh, Mariko; Watanabe, Gen; Terranova, Paul F.; Arai, Koji Y.; Uehara, Kohkichi; Groome, Nigel P.; Taya, Kazuyoshi

doi:10.1677/joe.0.1720247

Cited by 10 publications

(16 citation statements)

References 30 publications

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“…Our immunohisochemical approach suggests that the inhibin/ activin subunits bA and bB localize in the syncytiotrophoblast of the placenta, indicating secretion of activin A, AB, or B from these cells. From these results, in the second half of pregnancy in the golden hamster, we postulate that placenta is a potent source of activin A, consistent with our previous report [10]. Activin was discovered to be a secretagogue factor of FSH [12,23,24].…”

Section: Discussionsupporting

confidence: 90%

“…It is believed that in the golden hamster, the antral follicles that develop in the second half of pregnancy supply enough estrogens to maintain pregnancy, leading to parturition. We previously reported that during this period, large amounts of activin A are secreted from the placenta [10]. Our previous studies also suggest that this activin A is the factor that is involved in developing the antral follicles that emerge at the same time during the second half of pregnancy.…”

Section: Introductionmentioning

confidence: 77%

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Placental activin A is required for follicular development during the second half of pregnancy in the golden hamster (Mesocricetus auratus)

Furuta

Arakawa

Shi

et al. 2008

Endocr

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Numerous antral follicles develop during the second half of pregnancy in the golden hamster even though LH and FSH are maintained at basal levels. To investigate the possible hormone actions of activin A associated with follicular development, pregnant golden hamsters were placentectomized on day 6 of pregnancy and animals were sacrificed at day 8, 10, 12, or 14 of pregnancy. There was a drastic decrease in the plasma concentrations of activin A from day 10 of pregnancy in the operated group compared to the controls. Positive immunohistochemical staining of inhibin/activin subunits bA and bB in the syncytiotrophoblast of the placenta revealed the source of activin A, AB, or B. The number of healthy follicles did not change until day 12 between the operated and the control groups, but decreased in numbers in the operated groups thereafter. The decreased concentrations of inhibin A, B, and estradiol-17b in the operated groups at day 10 and 12 correlated well with the number of mature follicles in response to hCG treatment. In conclusion, we revealed that activin A secreted from the placenta induces folliculogenesis to maintain the high levels of estradiol-17b needed to induce uterine dilatation for fetus growth and impending parturition.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 77%

Placental activin A is required for follicular development during the second half of pregnancy in the golden hamster (Mesocricetus auratus)

Furuta

Arakawa

Shi

et al. 2008

Endocr

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“…Both A and B subunits can also combine with the subunit and form inhibin-A ( A) and -B ( B) respectively. In the ovary, activin-A is the most studied type (Tisdall et al 1994, Yokota et al 1997, Zhao et al 2001, Thomas et al 2003 and plays an important role in ovarian follicle development (Ohshima et al 2002, Lovell et al 2003, but activin-B has also been described (Bristol & Woodruff 2004). The activities of activin are modulated by its binding protein follistatin, which was originally purified from mammalian follicular fluid as a FSH inhibitor (Phillips & de Kretser 1998).…”

Section: Introductionmentioning

confidence: 99%

Gene expression and protein localisation for activin-A, follistatin and activin receptors in goat ovaries

Silva¹,

Hurk²,

Tol³

et al. 2004

Journal of Endocrinology

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We studied the protein and mRNA expression of activin-A, follistatin and activin receptors in goat ovaries to find evidence of their possible role in ovarian activity, particularly in the various stages of follicle development. Ovaries of cyclic goats were collected and then either fixed in paraformaldehyde for immunohistochemical localisation of activin-A, follistatin, activin receptors IIA/B (ActR-IIA/B) and IA (ActR-IA) proteins or used to obtain samples to demonstrate mRNA expression of activin-A ( A subunit), follistatin, ActR-IIA, -IIB, -IA and -IB, using RT-PCR. For this latter goal, primordial, primary and secondary follicles were isolated mechanically, washed to remove the stromal cells and then used for RT-PCR. In addition, oocytes, cumulus, mural granulosa and theca cells from small (<3 mm) and large (3-6 mm) antral follicles, luteal cells and surface epithelium were collected to study mRNA expression. Activin-A and follistatin proteins were found in oocytes of all follicle classes, granulosa cells from the primary follicle stage onwards, theca cells of antral follicles, corpora lutea and ovarian surface epithelium. In antral follicles, these proteins were detected both in cumulus and mural granulosa cells. ActR-IIA/B protein was found at the same follicular sites, and also in granulosa cells of primordial follicles onward. The localisation of ActR-IA corresponded with that of ActR-IIA/B, but the former protein was absent in the theca of large antral follicles. The mRNAs for activin-A ( A subunit), follistatin, and ActR-IIA, -IIB, -IA and -IB were detected at all follicular and cellular types studied, except that ActR-IIB was not found in follicles that had not developed an antrum yet. In conclusion, in goat ovaries, transcripts of activin-A ( A subunit), its receptors and its binding protein follistatin are expressed and their proteins formed at all follicular stages and in corpora lutea. These findings indicate a role of activin-A in the local regulatory system during the entire follicular development and during luteal activity.

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“…and estradiol-17β is altered [2,3]. Maximal values of circulating inhibins, activin A, progesterone and estradiol-17β are noted during the second half of pregnancy, followed by a decrease at the end of pregnancy [2,3].…”

mentioning

confidence: 98%

“…Maximal values of circulating inhibins, activin A, progesterone and estradiol-17β are noted during the second half of pregnancy, followed by a decrease at the end of pregnancy [2,3]. In addition, a large number of antral follicles develop during the second half of pregnancy [4], whereas all large antral follicles degenerate at the end of pregnancy because of a lack of post partum ovulation [4,5], as seen in rats [6] and mice [7].…”

mentioning

confidence: 99%

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

Cited by 10 publications

References 30 publications

Placental activin A is required for follicular development during the second half of pregnancy in the golden hamster (Mesocricetus auratus)

Placental activin A is required for follicular development during the second half of pregnancy in the golden hamster (Mesocricetus auratus)

Gene expression and protein localisation for activin-A, follistatin and activin receptors in goat ovaries

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

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