Heterologous gap junctions between oocyte and follicle cells inBufo arenarum: Hormonal effects on their permeability and potential role in meiotic arrest

Abstract

The physiological significance of follicle cell-oocyte gap junctional coupling in the ovarian follicle Bufo arenarum was investigated. Lucifer Yellow injected into the oocyte readily passed to the overlying follicle cells, demonstrating effective dye coupling. We determined that the gap junction coupling varies during the annual sexual cycle. In winter there is a marked decrease in the amount or absence of heterologous gap junction contacts. In contrast, during the breeding season, gap junctions were normally coupled. We studied in vivo and in vitro the effects of frog pituitary hormone (FPH) and follicle stimulating hormone (FSH) on gap junction coupling. The results suggest that FSH induce the coupling of gap junctions enabling a greater metabolic cooperation necessary for oocyte growth and maintenance. On the other hand, nuclear maturation under physiological conditions seemed to have a direct consequence on the gap junction uncoupling and the interruption of the gap junctional flow of an oocyte maturation inhibition factor by the effects of LH-like gonadotropin or progesterone. © 1996 Wiley-Liss, Inc.