Renal excretion of pyruvate, lactate and alpha-ketoglutarate in kidney donors before and after nephrectomy and in patients with terminal uremia.

The excretional patterns of lactate, pyruvate and alpha-ketoglutarate have been investigated in 7 patients with terminal uremia and in 10 kidney donors with normal renal function before and after unilateral nephrectomy. Methods for analysis of the three substances in urine were elaborated. In all patients, the levels of renal excretion of lactate and pyruvate were very low, and clearance values were independent of the glomerular filtration rate (GFR). alpha-ketoglutarate clearance varied to some extent with renal function, but no correlation to GFR was found, and exceeded the GFR in uremic patients, indicating that the net result of renal handling of alpha-ketoglutarate may be a tubular secretion.