Phosphorylation and expression of connexin-43 ovarian gap junction protein are regulated by luteinizing hormone.

摘要: One important role of the junctional communication in ovarian follicle is to mediate transmission cAMP, regulatory signal that maintains oocyte meiotic arrest. Luteinizing hormone (LH) interrupts cell-to-cell within follicle, leading a decrease intraoocyte concentrations cAMP followed by resumption meiosis. Our experiments were directed at exploration mechanisms involved LH-induced breakdown preovulatory follicle. Immunofluorescence and Western blot analysis, using highly specific antibodies, showed connexin-43 (Cx43), gap junction protein, present cytoplasmic membranes follicular cells multiple phosphorylated forms. The relative amounts different forms Cx43 vary response LH: short time exposure (10 min) stimulated phosphorylation immediate dephosphorylation, while longer incubations (8 24 h) with this resulted elimination protein. Forskolin mimicked phosphorylation/dephosphorylation, as well protein level. A gonadotropin-releasing analog (GnRHa) also induced an phosphorylation/dephosphorylation later reduction amount Cx43. direct PKC activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), was completely blocked kinase C inhibitor, staurosporine. This inhibitor partially interfered LH, but not forskolin-induced Analysis effect LH on gene expression revealed significant (45%) mRNA level h incubation. drop GnRHa. results suggest gating mechanism junctions rat follicles comprised two steps: represented change state manifested level, due attenuation its expression. Phosphorylation may occur through PKA-, PKC-dependent pathways.