IMCD cells cultured from Dahl S rats absorb more Na+ than Dahl R rats.
Dahl salt-sensitive (S) rats develop hypertension in response to a high-salt diet, whereas 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 whether there were intrinsic differences. Monolayers obtained from prehypertensive 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 rat monolayers always displayed higher transport rates than R rat monolayers with the same treatment. The Na+ entry pathway in both S and R rat monolayers was via an 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 adenosine 3',5'-cyclic monophosphate 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.
Husted
R F
RF
Department of Internal Medicine, University of Iowa, Iowa City, USA.
Takahashi
T
T
Stokes
J B
JB
D000818:Animals; D000838:Anions / Q000378:metabolism; D001692:Biological Transport; D002455:Cell Division; D002478:Cells, Cultured; D003345:Corticosterone / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics; D004553:Electric Conductivity; D004734:Energy Metabolism; D005260:Female; D006973:Hypertension / Q000139:chemically induced* / Q000235:genetics*; D007679:Kidney Medulla; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains / Q000235:genetics; D012964:Sodium / Q000493:pharmacokinetics*; D012965:Sodium Chloride / Q000494:pharmacology*
D000838:Anions; D012965:Sodium Chloride; D012964:Sodium; D003345:Corticosterone