Three-dimensional analysis of connexin 43 gap junction in the ex vivo rat seminiferous tubules: short-term effects of hormonal effectors.

Cx43 gap junctions are essential for proliferation, differentiation, and apoptosis of germ cells during spermatogenesis. However, only few and indirect observations have been reported on the distribution of Cx43, the predominant Cx within the seminiferous tubules. In the present study, we developed an innovative method that allows visualization of the three- dimensional localization of Cx43 associated with gap junctions and their functionality in isolated spermatogenic stage-specific seminiferous tubules. Cx43 gap junctions were present between myoid cells, between Sertoli cells, and between Sertoli and germ cells. Cx43 levels and coupling were stage-dependent with higher values at stages VI-VIII of spermatogenesis and markedly reduced at stages IX-X. Short-term exposure of seminiferous tubule fragments at stages VI-VIII and of the 42GPA9 Sertoli cell line transfected with a Cx43-GFP vector, to FSH, cAMP, DHT, and 17beta-E(2) significantly altered Cx43 distribution as well as gap junction coupling. These observations highlight a nongenomic effect of these testicular effectors on Cx43 gap junction.