Imcd cells cultured from dahl s rats absorb more na+ than dahl r
rats.
Husted, Russell F., Takeshi Takahashi, and John B. Stokes.
Laboratory of Epithelial Transport, Department of Internal
Medicine, University of Iowa and The Department of Veterans Affairs
Medical Center, Iowa City, IA 52242
APStracts 3:0140F, 1996.
Dahl salt sensitive (S) rats develop hypertension in response to a
high salt diet while Dahl salt resistant (R) rats do not. There is
good evidence that the Dahl S kidneys have diminished natriuretic
capacity. We studied the rate of Na+ transport by primary cultures of
the inner medullary collecting duct from these two strains, to
determine if there were intrinsic differences. Monolayers obtained
from pre-hypertensive S rats transported Na+ at twice the rate as
monolayers from age matched R rats. Mineralocorticoid and
glucocorticoid hormones increased Na+ transport from both strains;
the S monolayers always displayed higher transport rates than R
monolayers with the same treatment. The Na+ entry pathway in both S
and R monolayers was via a Na+ channel. The difference in Na+
transport was not explained by a difference in the metabolism of
corticosterone, ATP content, citrate synthase activity,
ultrastructural appearance, or rate of maturation. Monolayers from S
rats tended to have higher protein and DNA content, but these
differences could not account for the difference in Na+ transport.
Anion secretion in response to cAMP agonists was similar. These
results demonstrate intrinsic differences in renal tubular cells that
may play an important role in the pathogenesis of salt-sensitive
hypertension.
Received 12 October 1995; accepted in final form 30 July 1996.
APS Manuscript Number F342-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996