QUANTITATIVE HISTOCHEMISTRY OF THE KIDNEY. I. SEGMENTAL DISTRIBUTION OF ENZYMES IN THE RENAL PROXIMAL TUBULE OF NORMAL RATS

Abstract

The activities of eight enzymes were measured with quantitative microchemical techniques in 0.005 to 0.1 µg samples of convoluted and straight portions of the renal proximal tubules of rats. Satisfactorily homogeneous analytical data were obtained from samples dissected directly from frozen-dried sections. Significant differences between the two regions were found in the activity of each of the eight enzymes. Malic dehydrogenase, lactic dehydrogenase, isocitric dehydrogenase, and glutamic-oxalacetic-transaminase were more active in the convoluted than in the straight portion while glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, glutamic dehydrogenase, and alkaline phosphatase were more active in the straight segment.