Effects of low-potassium diet on N-ethylmaleimide-sensitive ATPase in the distal nephron segments.
The present study was undertaken to investigate whether or not potassium deficiency influences N-ethylmaleimide (NEM)-sensitive ATPase in the distal nephron segments of the rat. One group of animals was fed a low-K diet, whereas the normal K-group was given the same diet after supplementation with KCl. The nephron segments examined were: the medullary and cortical thick ascending limbs, the distal convoluted tubule, and the cortical, outer and inner medullary collecting ducts. NEM-sensitive ATPase activity in microdissected segments was measured by a fluorometric microassay. The plasma K+ concentration in the low-K group was 3.1 +/- 0.3 mEq/l compared with 4.2 +/- 0.1 mEq/l in the normal-K group. NEM-sensitive ATPase activity in the outer medullary collecting duct of low-K diet animals was significantly greater than in normal-K animals. There was no significant difference in NEM-sensitive ATPase activity between the two groups of animals in the other nephron segments examined. It is suggested that NEM-sensitive H-ATPase activity in the outer medullary collecting duct is modulated by the potassium status of the animal.
Department of Pharmacology and Therpeutics, University of Florida College of Medicine, Gainesville.
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Garg
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Narang
D000818:Animals; D001835:Body Weight; D004032:Diet; D005033:Ethylmaleimide / Q000494:pharmacology*; D007668:Kidney / Q000473:pathology; D008297:Male; D009399:Nephrons / Q000201:enzymology*; D009929:Organ Size; D011188:Potassium / Q000097:blood / Q000652:urine; D011191:Potassium Deficiency / Q000097:blood / Q000201:enzymology* / Q000652:urine; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D006180:Proton-Translocating ATPases; D005033:Ethylmaleimide; D011188:Potassium