Evidence for the role of follicle stimulating hormone in maintaining the oocyte meiotic arrest in pre-antral follicles.
The study was designed to clarify the physiological role of FSH in maintaining the meiotic arrest in vitro of oocytes derived from intact and from hypophysectomized hamsters. The sensitivity to FSH in maintaining the meiotic arrest of oocytes during incubation of pre-antral follicles of adult golden hamsters was estimated: log dose-response curves were characterized by an ED50 of about 0.2 pg FSH/ml (= 1 microU). After hypophysectomy oocytes of the pre-antral follicles were screened for the presence of a germinal vesicle (GV). The breakdown of the GV (GVBD) rose from 0 on day 0 to 48.8 +/- 13.8% on day 1, to 55.9 +/- 6.8% on day 2 and to 64.3 +/- 7.4 on day 6 (p < 0.001 vs day 0). Incubation without FSH of the pre-antral follicles obtained from the same hypophysectomized animals showed an almost complete disappearance of the GV at the same time intervals. Incubation with 2 pg FSH/ml (= 10 microU) still demonstrated the inhibiting effect of FSH on the meiotic resumption: 13.4 +/- 4.3% (day 0), 36.9 +/- 16.3% (day 1), 38.7 +/- 21.0% (day 2) and of 38.1 +/- 12.6% (p > 0.1) on day 6. These results demonstrate that very low doses of FSH are able to maintain the meiotic arrest in oocytes of pre-antral follicles of the golden hamster and that deprivation of FSH by hypophysectomy involves a disappearance of GV oocytes to a certain extent.
Goverde
H J
HJ
Department of Obstetrics & Gynaecology, Catholic University, Nijmegen, The Netherlands.
Janssen
G H
GH
D000818:Animals; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology / Q000502:physiology*; D007016:Hypophysectomy; D008540:Meiosis / Q000502:physiology; D008647:Mesocricetus; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D006080:Ovarian Follicle / Q000166:cytology / Q000502:physiology*
D005640:Follicle Stimulating Hormone