Substrate oxidation and inhibition of sodium transport in the isolated perfused rat kidney.
The relationship between the oxidative substrate-turnover-rate and the active Na+-transport was investigated. Our special interest was directed to the possible dependence of the oxidative turnover-rate of one selected substrate from the mode of reduction of the Na+-transport. The following methods were used: 1. Blocking the active Na+-transport by the addition of ouabain to the perfusion medium (0, 5 mg/ml); 2. Reduction of the sodium concentration in the perfusion medium to 100mM substituting NaCl by Tris/HCl; 3. Reduction of the perfusion pressure resulting in a low GFR and a low tubular Na+-load. The perfusion medium contained the following substrates in normal plasma concentrations: Na-palmitate, Na-oleate, Na-propionate, Na-acetate, D-glucose, Na-pyruvate, Na-L-lactate and Na-glutamate. The substrate in question was uniformly 14C-labelled; its amount oxidized per unit time was calculated on the basis of the 14CO2 formed. The following substrates were studied; Na-acetate, Na-pyruvate and Na-L-lactate. There were no significant differences between the results of the three methods described.
D000085:Acetates / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects*; D002245:Carbon Dioxide / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D005919:Glomerular Filtration Rate; D007668:Kidney / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D008297:Male; D008861:Microsomes / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology; D010101:Oxygen Consumption; D011773:Pyruvates / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D000085:Acetates; D007773:Lactates; D011773:Pyruvates; D002245:Carbon Dioxide; D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases