The interaction between gluconeogenic metabolism and accumulation of phosphate by chick kidney tubule cells

Abstract

Pyruvate promotes both phosphate uptake and glucose synthesis by isolated chick kidney proximal tubule cells. 3-Mercaptopicolinate inhibits both glucose synthesis and the promoted phosphate accumulation to the same extent. Glycerol also stimulates glucose synthesis, but does not affect phosphate accumulation. Oxygen utilization by the tissue is slightly stimulated by glycerol and pyruvate, but the enhancement of uptake by pyruvate is unlikely to result from raised cellular oxidative phosphorylation. The action of pyruvate is not a direct effect on the phosphate transporter, or on the transport of phosphate across the basolateral membrane, but entails an obligatory flux to triose phosphate.

Study of the mechanism by which the Na+-Pi co-transporter of mouse kidney proximal-tubule cells adjusts to phosphate depletion

“…Hexokinase was determined by the method of Chou & Wilson (1975), lactate dehydrogenase by the method of Vassault (1983) and alkaline phosphatase by the procedure of Jahan & Butterworth (1986). Gluconeogenesis from pyruvate was measured by the method described by Grahn et al (1985). Protein was determined by the biuret method, with bovine serum albumin as standard (Plummer, 1987).…”

“…The method was essentially the same as that described by Grahn et al (1985) with chick kidney cells. The tubule cells were incubated at 37°C with gentle shaking in isolation medium containing I mM-Pi and 1 mg of bovine serum albumin/ml.…”