Metabolic Adaptation of the Pentose Phosphate Cycle in the Renal Cortex of Rats. I. Nutritional Regulation of the Glucose-6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase Activities | ADAPTACION METABOLICA DEL CICLO DE LAS PENTOSAS FOSFATO EN CORTEZA RENAL DE RATA. I.-Regulacion NUTRICIONAL DE LAS ACTIVIDADES GLUCOSA 6-Fosfato DESHIDROGENASA Y 6-Fosfogluconato DESHIDROGENASA