In vitro steroid production by follicles of frog Rana esculenta: mammalian gonadotropin-releasing hormone effects.
The effects of mammalian gonadotropin-releasing hormone on ovarian release of progesterone, androgens and estradiol-17 beta were studied in vitro by a superfusion system carried out on follicles of adult female Rana esculenta, collected at different periods of the annual reproductive cycle. The follicles were superfused with medium alone, pituitary, mammalian gonadotropin-releasing hormone, or pituitary plus mammalian gonadotropin-releasing hormone. For follicles obtained in the prereproductive period, pituitary plus mammalian gonadotropin-releasing hormone increased the estradiol values much more than pituitary alone. In the reproductive period, pituitary alone increased the estradiol values much more than pituitary plus mammalian gonadotropin-releasing hormone. For follicles obtained in the recovery period, mammalian gonadotropin-releasing hormone alone stimulated the highest estradiol production, and pituitary plus mammalian gonadotropin-releasing hormone increased the estradiol values much more than pituitary alone. The results reported here suggest that mammalian gonadotropin-releasing hormone and/or pituitary have a direct effect on ovarian estradiol secretion, and that this effect varies with the annual reproductive cycle.
Zerani
M
M
Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
Gobbetti
A
A
Polzonetti-Magni
A
A
D000728:Androgens / Q000378:metabolism*; D000818:Animals; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D066298:In Vitro Techniques; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D011374:Progesterone / Q000378:metabolism*; D011893:Rana esculenta / Q000378:metabolism*
D000728:Androgens; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol