AJP - Regulatory, Integrative and Comparative Physiology, Vol 260, Issue 5 879-R888, Copyright © 1991 by American Physiological Society

ARTICLES

Characteristics of renal transport of taurine in reptilian brush-border membranes

S. Benyajati and J. L. Johnson
Department of Physiology and Biophysics, College of Medicine, University of Oklahoma, Health Sciences Center, Oklahoma City 73190.

We examined characteristics of taurine transport across renal brush-border membranes (BBM) of the garter snake (Thamnophis sirtalis), a species that demonstrates both net reabsorption and secretion of taurine in vivo. Transport was examined by a rapid filtration technique at 25 degrees C. Inwardly directed Na+ gradient specifically stimulated taurine uptake. Under initial taurine equilibrium condition, a small overshoot of taurine uptake driven by an inwardly directed NaCl gradient could be observed. No stimulation of taurine uptake was observed under Na+ equilibrium or K+, Li+, or choline gradients conditions. Reptilian renal BBM taurine transport also displayed specific Cl- requirement: replacement of NaCl by NaSCN or Na(+)-gluconate gradients inhibited taurine uptake. The uptake was stimulated under Cl- gradient compared with Cl- equilibrium conditions. Taurine transport was not stimulated by H+ gradient in either direction, although it was inhibited by acidic pH (less than 7.0). Amiloride and furosemide had no effects. The transport was electrogenic, stimulated by an inside negative membrane potential, and inhibited by other beta-amino acids. Overall, the reptilian BBM transport system for taurine resembles those observed in both mammalian and fish renal BBM.

This article has been cited by other articles:

				S. Benyajati and J. L. Renfro Taurine secretion in primary monolayer cultures of flounder renal epithelium: stimulation by low osmolality Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2000; 279(2): R704 - R712. [Abstract] [Full Text] [PDF]