Renal Na excretion in dehydrated and rehydrated adrenalectomized sheep maintained with aldosterone.
The effect of water deprivation for 19 h on renal Na excretion of conscious adrenalectomized (ADX) sheep maintained on a constant intravenous infusion of aldosterone and cortisol (ADX-constant steroid sheep) was investigated. Both ADX and normal sheep showed large increases in renal Na excretion when they were deprived of water. ADX-constant steroid sheep also exhibited a normal postprandial natriuresis 3-6 h after feeding, whether or not water was available to drink. In another experiment, sheep deprived of water for 41 h were then allowed to drink water. Both normal and ADX-constant steroid sheep exhibited a large reduction of renal Na excretion in the 6 h after rehydration. Changes in plasma Na and K concentration and osmolality were similar in normal and ADX-constant steroid sheep during periods of dehydration and rehydration. These results show that change in aldosterone secretion is not a major factor in causing either dehydration-induced or postprandial natriuresis. Neither is it a major cause of rehydration-induced renal Na retention.
McKinley
M J
MJ
Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria 3052, Australia. mmck@hfi.unimelb.edu.au
Evered
M D
MD
Mathai
M L
ML
D000315:Adrenalectomy; D000450:Aldosterone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001835:Body Weight; D003681:Dehydration / Q000378:metabolism* / Q000628:therapy; D005260:Female; D005440:Fluid Therapy; D006854:Hydrocortisone / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D009994:Osmolar Concentration; D011188:Potassium / Q000652:urine; D012756:Sheep; D012964:Sodium / Q000097:blood* / Q000652:urine*; D014868:Water Deprivation
D000450:Aldosterone; D012964:Sodium; D011188:Potassium; D006854:Hydrocortisone