Kidney Function and Net Glucose Production in Normal and Acidotic Sheep

Abstract

Net glucose production and renal function were assessed simultaneously in normal sheep which were subsequently made acidotic by ammonium chloride administration. Arteriovenous differences in glucose concentration were measured, together with p-aminohippuric acid and inulin clearances in one kidney. In normal sheep there was a small net output of glucose by the kidney [20 Ilg min- 1 (kg body weight)-l] which was increased threefold during acidosis. The increase was associated with an elevated venous-arterial difference in glucose concentration and a fall in renal blood flow, while glomerular filtration rate did not change. The increase in the proportion of blood being filtered indicates that there is a greater perfusion of the active zone of the cortex, which is the major site of glucose production in the kidney. This suggests that changed intrarenal events are associated with the physiological response of the kidney to altered acid-base status. The contribution by the kidneys to the overall glucose requirements in sheep, even during acidosis, is unlikely to be greater than 6%.