Nephron electrolyte transport and sodium-potassium adenosine triphosphatase activity: influence of nicotine in rat and rabbit.
1. The influence upon mammalian renal epithelial transport of L-nicotine was studied in different types of experiments. 2. The kidney in situ (rat), when infused with nicotine (1 mg hr-1 kg-1 I.V.), lowered its absolute and fractional K+-absorption significantly and reversibly, but Na+-absorption did not change. Effects on glomerular function and an irreversible effect upon epithelial Na+ and K+ absorption were prevailing at higher infused amounts (10 or 50 mg hr-1 kg-1). 3. Single dissected nephron segments (collecting tubule, rabbit) were perfused in vitro, and the Na+ and K+-transtubular net flux was measured while L-nicotine (50 ng/ml.) had been added to the contraluminal side of the epithelium. Both, Na+-absorption and K+-secretion were decreased reversibly. 4. The activity of the Na+-K+-activated ATPase was significantly decreased in the cortical collecting tubule and in the proximal convoluted tubule of the rabbit after incubation of single in vitro dissected nephron segments with L-nicotine (50 or 100 ng/ml.). In contrast, nicotine added to a homogenate of renal cortical tissue had no effect on the Na+-transport enzyme or on key enzymes of glycolysis and gluconeogenesis. 5. These observations on the kidney in situ and on defined, perfused and non-perfused nephrons in vitro suggest that L-nicotine has dose-dependent, direct epithelial and mediated systemic effects on mammalian renal ion transport.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004848:Epithelium / Q000378:metabolism; D005260:Female; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D007672:Kidney Cortex / Q000201:enzymology; D008297:Male; D009399:Nephrons / Q000201:enzymology / Q000378:metabolism*; D009538:Nicotine / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D009538:Nicotine; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium