BOVINE PREANTRAL FOLLICLES AND ACTIVIN - IMMUNOHISTOCHEMISTRY FOR ACTIVIN AND ACTIVIN RECEPTOR AND THE EFFECT OF BOVINE ACTIVIN-A IN-VITRO

Activin was originally isolated from follicular fluid as a factor stim ulating FSH from the pituitary. Recent studies also suggest a local ro le for activin in the development of preantral and early antral follic les. In the present study, activin and activin receptor immunoreactivi ty are shown in oocyte and granulosa cells of bovine preantral follicl es. In addition, activin immunoreactivity was observed in the theca of secondary follicles. During culture of isolated preantral follicles, activin increased follicular growth and granulosa cell proliferation i n a dose-dependent manner. This increase was further stimulated by add ition of FSH. In conclusion, activin and its receptor are present on b ovine preantral follicles, and additional activin stimulates developme nt of those follicles. (C) 1997 by Elsevier Science Inc.