Increase of ornithine decarboxylase activity elicited by reserpine in the peripheral and central monoaminergic systems of the rat.

Ornithine decarboxylase activity was increased about tenfold in adrenal glands and in brain regions preponderantly containing aminergic neurons, by a single dose of 16 mumol/kg of reserpine. Maximal enzyme activity in the adrenal glands was observed at about 8 hr after reserpine administration. The ornithine decarboxylase activity-time curves in the brain regions showed a concomitant polyphasic course, with the highest maximum at 12 hr postinjection. Ornithine decarboxylase induction is discussed as an early event in the cascade of molecular events preceding the induction of cell typic enzymes.