Immunolocalization of the secretory isoform of Na-K-Cl cotransporter in rat renal intercalated cells.

摘要: Two bumetanide-sensitive ion cotransporters that carry Na+, K+, and Cl- in a coupled fashion have been identified. One type, the "absorptive" isoform, carries these ions across apical plasma membrane of thick ascending limb Henle9s loop. Another "secretory" cotransporter, has identified number epithelial tissues by physiological means, but its sites expression kidney not fully characterized. Complementary DNA believed to code for secretory isoform (called "BSC2" or "NKCC1") recently cloned. This study used specific affinity-purified antipeptide antibody this protein immunolocalization rat kidney. Immunoblot studies using show abundant immunoreactivity against bands 140-190 120 kd parotid gland, colon, stomach, where form cotransporter techniques. distribution supports hypothesis represents cotransporter. Studies revealed same are associated with fractions chiefly outer medulla. Immunolocalizations is selectively intensely localized basolateral subfraction medullary collecting duct cells. An independently produced monoclonal (T4) Na-K-Cl displays localization. Dual localizations respect principal cells (aquaporin-2) intercalated (band 3 H(+)-ATPase) alpha-intercalated rat. distinctive localization suggests may play role renal NH4+ and/or acid secretion cell type.