Renal function and sodium balance in conscious Dahl S and R rats.
Renal transplantation studies have indicated that some form of renal dysfunction underlies the development of hypertension in Dahl salt-sensitive (S) rats. In the present study, we compared renal hemodynamic and tubular function of conscious Dahl S and salt-resistant (R) rats. Prehypertensive Dahl S rats had a blunted natriuretic response to an intravenous isotonic sodium chloride load compared with the responses of normotensive Dahl R or hypertensive Dahl S rats. This difference was probably not related to a generalized defect in renal tubular handling of sodium and water, since prehypertensive Dahl S rats excreted quantities of sodium comparable to those of R or hypertensive S rats when infused with hypertonic sodium chloride solutions. Dahl S rats also elevated free water clearance and lowered urine osmolality similar to R rats when challenged with a hypotonic saline load. Renal blood flows and glomerular filtration rates were similar in prehypertensive Dahl S, hypertensive Dahl S, and Dahl R rats. The possible link between sodium retention and the development of hypertension in Dahl S rats was examined further by measuring the changes in sodium and water balance, extracellular fluid volume (ECV), and blood pressure after exposure to an 8% sodium chloride diet. No differences could be detected in the salt and water balances of Dahl S and R rats exposed to a high-salt diet for 14 days. ECV increased significantly by 10% in Dahl S rats on the 1st day of a high-salt diet, whereas no change was observed in Dahl R animals.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D001794:Blood Pressure; D001826:Body Fluids / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D003243:Consciousness; D004351:Drug Resistance; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D006439:Hemodynamics; D006973:Hypertension / Q000139:chemically induced; D007668:Kidney / Q000502:physiology*; D007684:Kidney Tubules / Q000502:physiology; D051381:Rats; D011922:Rats, Mutant Strains; D012079:Renal Circulation; D012964:Sodium / Q000097:blood / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*
D012965:Sodium Chloride; D012964:Sodium