Stage-specific and differential expression of gap junctions in the mouse ovary: connexin-specific roles in follicular regulation

Gap junction communication plays an essential role in follicle growth. Immu nocytochemistry and confocal microscopy were used to examine the expression of gap junction connexins of the alpha and beta subfamilies in follicles f rom primordial to preovulatory stages in the ovaries of prepubertal and adu lt mice. Connexin-specific antibodies detested alpha (1), alpha (4), alpha (6), beta (1), beta (2) and beta (4) connexins within follicles. In adult o varies connexin immunolabeling was stronger in larger (more mature) follicl es than it was in smaller follicles, with comparatively reduced labelling d etected in prepubertal ovaries. In healthy Collides, labelling for alpha su bfamily connexins was detected between granulosa cells, whereas labelling f or beta subfamily connexins was found in the theca. Labelling for beta subf amily connexins and alpha (4) connexin (preantral stage) was detected on th e oocyte surface membrane. in atretic follicles, labelling for beta (4) con nexin appeared between the granulosa cells. These results demonstrate that alpha and beta connexin subfamilies are segregated to separate cellular com partments in the mouse follicle. The results are discussed in the light of possible roles for differential gap junctional communication in the regulat ion of folliculogenesis, oocyte maturation and atresia.