Role of substrates and nucleotides in phosphate uptake by rabbit renal cortical cells.

We investigated the viability of isolated rabbit renal cortical cells and the effect of metabolic intermediates on phosphate uptake. Glucose production and its stimulation by hormones was similar to that previously reported for renal tubules. The uptake of alpha-methylglucoside and phosphate was reduced by 90% when sodium was removed from the media. ATP content of the cells was 9.4 +/- 0.7 nmol/mg protein. Succinate and fumarate stimulated phosphate uptake in a dose-dependent manner by 30-60%. Valeric acid (1 mM) and butyric acid (10 mM) stimulated phosphate uptake by 20-30%. Glucose and fructose stimulated phosphate uptake by 18% but only at low concentrations (0.1 mM). Exogenous nucleotides had no effect on phosphate uptake at 0.2 mM, but inhibited 2.4 mM phosphate uptake at 2 mM. We conclude: rabbit renal cortical cells in suspension are metabolically and functionally viable; tricarboxylic acid cycle and glycolytic intermediates as well as short chain fatty acids can stimulate phosphate uptake, and exogenous nucleotides are hydrolyzed to produce free phosphate causing inhibition of isotopic phosphate uptake.