HETEROLOGOUS GAP-JUNCTIONS BETWEEN OOCYTE AND FOLLICLE CELLS IN BUFO-ARENARUM - HORMONAL EFFECTS ON THEIR PERMEABILITY AND POTENTIAL ROLE IN MEIOTIC ARREST

The physiological significance of follicle cell-oocyte gap junctional coupling in the ovarian follicle Bufo arenarum was investigated. Lucif er Yellow injected into the oocyte readily passed to the overlying fol licle cells, demonstrating effective dye coupling. We determined that the gap junction coupling varies during the annual sexual cycle. In wi nter there is a marked decrease in the amount or absence of heterologo us 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 hormo ne (FSH) on gap junction coupling. The results suggest that FSH induce the coupling of gap junctions enabling a greater metabolic cooperatio n necessary for oocyte growth and maintenance. On the other hand, nucl ear 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. (C) 1996 Wiley-Liss, Inc.