Natriuresis and chloruresis during hydropenia in the rat
Luke, R.G.
American Journal of Physiology 224(1): 13-20
1973
ISSN/ISBN: 0002-9513 PMID: 4683292 Document Number: 66447
The effect of water deprivation on NaCl in urine was studied in rats. Consistently increased losses of Na and Cl were present during 24 h of thirst with a range of intakes of Na and chloride, except when salt intake was sufficient to increase Na and chloride concentrations in urine above values found in the papillary interstitium. During water deprivation on a low-salt diet, papillary Na concentration was 331 m-equiv/kg tissue water and the calculated gradient for passive backdiffusion from the papilla to the collecting duct urine was 252 m-equiv/litre compared with 232 m-equiv/litre in normally hydrated rats. The losses of Na and Cl were maintained during hydropenia prolonged for 48 h. Pitressin during continued water intake also increased Na and Cl in urine. Deoxycorticosterone, 2 mg, in water deprivation prevented the increases. Creatinine, urea N and total osmolar excretion fell during hydropenia.