Biopterin cofactor biosynthesis: independent regulation of GTP cyclohydrolase in adrenal medulla and cortex

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Science  17 Jul 1981:
Vol. 213, Issue 4505, pp. 349-350
DOI: 10.1126/science.7017928


Guanosine triphosphate cyclohydrolase, the enzyme that is apparently rate-limiting in biopterin biosynthesis, is increased in adrenal cortex and medulla of rats treated with insulin or reserpine. Denervation and hypophysectomy block the increase in medullary and cortical enzyme activity, respectively, whereas cycloheximide presents the increase in both tissues. These results provide evidence for induction and regulation of guanosine triphosphate cyclohydrolase.