Different localization of ATP sensitive K+ channel subunits in rat testis.

ATP sensitive K(+) (K(ATP) ) channels are important linkage of cell membrane excitability to its cellular bioenergetic state. These channels are composed of pore-forming subunits and regulatory subunits. The present study focused on the cellular expressions and localizations of these subunits in rat testis. RT-PCR analysis showed that rat testis contained five K(ATP) channel subunits, Kir6.1, Kir6.2, SUR1, SUR2A and SUR2B. Immunoblot assay showed that proteins of Kir6.1, Kir6.2, SUR2A and SUR2B were expressed in rat testis. Immunohistochemistry revealed these K(ATP) channel subunits were positive in different localizations of spermatogenic cells, Sertoli cells and Leydig cells, which implies these subunits playing important roles in spermatogenesis. Co-localization of Kir6.2 with SUR2B was determined in acrosome or head cap of spermatids by double immunofluorescence analysis by indicating K(ATP) channel might be formed by Kir6.2 and SUR2B in acrosome of spermatids. Different localizations of the K(ATP) channel subunits in the cell membrane and membranous organelles of spermatogenic cells and Sertoli cells indicated the complex and multiple functions of K(ATP) channels in rat testis.