ADRENOCORTICOTROPIN-INDUCED GENERATION OF 5'-PHOSPHORIBOSYLPYROPHOSPHATE AND ITS RELATION TO NUCLEOTIDE SYNTHESIS IN ADRENAL CORTEX

Corticotropin added at a level of 1-0.01 nM to a high-speed supernatant fraction prepared from a homogenate of adrenal cortex stimulated the synthesis of uridine 5′-phosphate. Stimulus occurred in the presence of glucose 6-phosphate and NADP+. Corticotropin was thought to activate adrenal glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and thus the pentose phosphate pathway with an increase in 5′-phosphoribosylpyrophosphate. In the presence of [carboxy-14C]orotate, added or generated 5′-phosphoribosylpyrophosphate formed [carboxy-14C]orotidine 5′-phosphate. The subsequent decarboxylation of this latter compound gave rise to 14Co2 which was used as a measure of pyrimidine synthesis. Corticotropin also stimulated the rate of decarboxylation of [1-14C]glucose 6-phosphate added to the supernatant fraction. © 1969.