APStracts 5:0051F, 1998.

Cloning, renal distribution and regulation of the rat na+:hco3- cotransporter.. Burnham[, Charles E., Ob]lambda], Michael Flagella, Zhaohui Wang[lambda], Hassane Amlal[lambda], Gary. E. Shull, and Manoocher Soleimani[lamba]. Departments of [lambda] Medicine and Molecular Genetics, University of Cincinnati School of Medicine, Cincinnati, Ohio, and Veterans Affairs Medical Centers at Cincinnati

APStracts 5:0051F, 1998.

We recently reported the cloning and expression of a human kidney Na+:HCO3- cotransporter (NBC-1) (Burnham, C.E., Amlal, H., Wang, Z., Shull, G.E., and Soleimani, M. J.Biol.Chem.272:19111-19114, 1997). In order to expedite in vivo experimentation, we now report the cDNA sequence of rat kidney NBC-1. In addition, we describe both the organ and nephron segment distributions, and the regulation of NBC-1 mRNA under three models of pH stress: chloride depletion alkalosis (CDA), metabolic acidosis, and bicarbonate loading. Rat NBC-1 cDNA encodes an open reading frame of 1035 amino acids, with 96% and 87% identity to human and salamander NBC-1, respectively. Rat NBC-1 mRNA is expressed at high levels in kidney and brain, with lower levels in colon, stomach, and heart. None appears in liver. In the kidney, NBC -1 is expressed mainly in the proximal tubule, with traces found in medullary thick ascending limb and papilla. HCO3- loading decreased NBC-1 mRNA levels, which were unchanged either by metabolic acidosis or by CDA.

Received 6 October 1997; accepted in final form 19 February 1998.
APS Manuscript Number F322-7.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 9 March 1998