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Nephron electrolyte transport and sodium‐potassium adenosine triphosphatase activity: influence of nicotine in rat and rabbit.
Author(s) -
Horster M,
König T,
Schmid H,
Schmidt U
Publication year - 1979
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1979.sp012973
Subject(s) - potassium , adenosine triphosphatase , sodium , chemistry , endocrinology , medicine , nicotine , electrolyte , rabbit (cipher) , adenosine , atpase , biochemistry , biology , enzyme , organic chemistry , statistics , mathematics , electrode
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.