Direct Measurement of Endothelin Receptor in Human Bladder Base and Dome Using ¹²⁵I-Endothelin

Abstract

KONDO, S., FUSHIMI, E., MORITA, T. and TASHIMA, Y. Direct Measurement of Endothelin Receptor in Human Bladder Base and Dome Using ¹²⁵I-Endothelin. Tohoku J. Exp. Med., 1992, 167 (2), 159-161-The amount of endothelin receptor in human bladder base and dome was measured by radioligand binding techniques using ¹²⁵I-endothelin-1 (¹²⁵I-ET). Specimens were obtained from 5 patients who underwent total cystectomy under diagnosis of bladder cancer. ¹²⁵I-ET bound to the bladder base with the K_D value of 0.004±0.003nM and to the bladder dome with the K_D value of 0.007±0.003nM. These values were not significantly different. The B_max values (fmol/mg protein) of ¹²⁵I-ET binding to human bladder were 2.74±2.81 to the base and 47.3±9.52 to the dome. There were much larger amount of endothelin receptors in the dome compared to the base. The existence of endothelin receptors in human bladder suggests the possible roles of endothelin on the human bladder function.