Distribution of _α1- and _α2-Adrenoceptors in Brush Border and Basolateral Membranes from Rat Kidney Cortical Tubules

Abstract

To examine the localization of α-adrenoceptors within the kidney tubule, binding experiments with ¹²⁵I-HEAT and ³H-yohimbine were performed using cortical homogenates, basoalteral membranes (BLM) and brush border membranes (BBM). B_max values for ¹²⁵I-HEAT or ³H-yohimbine binding were 2.3 or 2.0-fold that of the homogenate in BBM and 8.2- or 10.7-fold in BLM, respectively. K_d values for ¹²⁵I-HEAT or ³H-yohimbine were not significantly different between BBM and BLM. These results indicate that both types of α-adrenoceptors seem to be localized largely in the BLM.