Sulfation in isolated kidney tubule fragments of rats. Dependence on inorganic sulfate.
Uptake and conjugation of sulfate was studied in isolated kidney tubule fragments of rats: Sulfate is rapidly taken up, and maximal cellular concentrations are attained after 5-10 min; intracellular steady-state levels depend on the sulfate concentrations of the medium and attain a maximal value at 2 mM. At 1 mM sulfate in the medium the ratio of intracellular/extracellular concentrations of the inorganic anion amount to about 0.25. Formation of 7-hydroxycoumarin sulfate increases almost linearly up to an extracellular sulfate concentration of 500 microM. Thereafter, rates of sulfation increase more slowly and maximal sulfation rates are attained at 2 mM sulfate. The data indicate that sulfation of 7-hydroxycoumarin proceeds at almost maximal rates in kidney tubule fragments at physiological serum sulfate concentrations.
D000818:Animals; D066298:In Vitro Techniques; D007684:Kidney Tubules / Q000378:metabolism*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D013431:Sulfates / Q000378:metabolism*; D014468:Umbelliferones / Q000378:metabolism
D013431:Sulfates; D014468:Umbelliferones; C031477:7-hydroxycoumarin