GLUTAMINE TRANSPORT IN RAT-KIDNEY MITOCHONDRIA IN METABOLIC-ACIDOSIS

Abstract

In order to study factors regulating renal ammoniagenesis, the transport and metabolism of L-glutamine were studied in mitochondria from kidneys of control and acidotic rats. On incubation in 1 mM [(14)C]glutamine, there was production and accumulation of [(14)C]glutamate within the matrix space. However no [(14)C]glutamine was detected in the matrix space, even with 10 mM [(14)C]glutamine as substrate or with inhibition of glutamine deamidation (low temperature, p-chloromercuribenzoate, mersalyl). These results suggest that glutamine crosses the inner membrane by a carrier-mediated step and that this step is rate-limiting in glutamine deamidation. In chronic acidosis there is a fourfold inc..