AJP - Renal Physiology, Vol 258, Issue 2 388-F396, Copyright © 1990 by American Physiological Society

ARTICLES

Proton gradient-dependent renal transport of glycine: evidence for vesicle studies

H. Roigaard-Petersen, H. Jessen, S. Mollerup, K. E. Jorgensen, C. Jacobsen and M. I. Sheikh
Institute of Medical Biochemistry, University of Aarhus, Denmark.

The characteristics of renal transport of glycine by luminal membrane vesicles isolated from either proximal convoluted part (pars convoluta) or proximal straight part (pars recta) of rabbit proximal tubule were investigated. In vesicles from pars convoluta two transport systems have been characterized: a Na(+)-dependent system with intermediate affinity (half-saturation 3.64 mM) and a Na(+)-independent system that, in the presence of H+ gradient (extravesicular greater than intravesicular), can accelerate the transport of glycine into these vesicles. This is the first demonstration of H(+)-glycine cotransport across the luminal membrane of rabbit kidney proximal convoluted tubule. By contrast, in membrane vesicles from pars recta, transport of glycine was strictly dependent on Na+ and occurred via a dual transport system, namely a high-affinity (half-saturation 0.34 mM) and a low-affinity system (half-saturation 8.56 mM). The demonstration of competition between the H(+)-gradient dependent uptake of glycine, L-alanine, and L-proline, but insignificant inhibition with L-phenylalanine in vesicles from pars convoluta suggests that glycine, L-proline, and L-alanine probably share a common proton gradient-dependent transport system. In vesicles from pars recta, the Na(+)-dependent uptake of glycine was inhibited by low concentrations of L-alanine and L-phenylalanine, whereas addition of L-proline to the incubation medium did not significantly alter the uptake of glycine, suggesting that the Na(+)-dependent high-affinity system for glycine located in pars recta is shared with the high-affinity L-alanine and L-phenylalanine but not L-proline transport system.

This article has been cited by other articles:

				S. Broer Amino Acid Transport Across Mammalian Intestinal and Renal Epithelia Physiol Rev, January 1, 2008; 88(1): 249 - 286. [Abstract] [Full Text] [PDF]

				L. Ingrosso, S. Marsigliante, V. Zonno, C. Storelli, and S. Vilella An L-proline-dependent proton flux is located at the apical membrane level of the eel enterocytes Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1619 - R1624. [Abstract] [Full Text] [PDF]