THE QUANTITATIVE HISTOCHEMISTRY OF THE SYMPATHOADRENAL SYSTEM II. ENZYMES OF THE CITRIC ACID, PENTOSE PHOSPHATE AND GLYCOGENOLYTIC PATHWAYS

The activities of enzymes from the citric acid cycle, pentose phosphate pathway and glycogen cycle were measured in collections of sympathoadrenal cells and compared with other neuronal groups. Enzymes from each pathway are found in groups of sympathetic neurons and adrenal medullary cells. The citric acid cycle has the highest capacity among glucose pathways in sympathoadrenal cells. Differences in glycolytic and citric acid cycle capacities between sympathetic ganglion and the other neuronal groups may be related to differences in capillary density. The capacity of the pentose phosphate pathway and reduced nicotinamide adenine dinucleotide phosphate-linked isocitric dehydrogenase is higher in sympathoadrenal cells than in the other cells surveyed. The enzyme activities in sympathetic ganglion are in excess of those needed to sustain the rates of glucose metabolism previously observed in this structure.