Triphosphopyridine nucleotide-linked dehydrogenases in the adrenal cortex in man: the effect of corticotrophin and the distribution of enzymes

Four TPN linked dehydrogenases – Isocitric Dehydrogenase, Glucose-6-phosphate Dehydrogenase, 6 Phosphogluconic Dehydrogenase and the Malic Enzyme – were studied in human adrenal cortex and found to be present almost exclusively in the soluble part of the cell sap. The effect of corticotrophin on these enzymes was studied by comparing the enzyme activities in the cortex of the adrenal glands removed before and after corticotrophin administration. Glucose-6-phosphate dehydrogenase showed marked increase in activity after corticotrophin administration. This increase was not parallel to the concomitant weight increase occurring in the adrenal gland. Glucose-6-phosphate dehydrogenase is uniformly distributed in the »normal« adrenal cortex. After corticotrophin administration however the increase takes place principally in the middle third of the cortex. These findings are discussed in relation to the current theories of the mechanism of corticotrophin action.