Ornithine dec arboxylase—apparent lack of involvement in the induction of n-acetyltransferase in rat pineal gland

Abstract

The potential role ornithine decarboxylase in the induction of serotonin- N-acetyltransferase in the rat pineal gland has been studied. The injection of isoproterenol (5 mg/kg, s.c.) resulted in an apparent induction of serotonin- N-acetyltransferase within 1 hr with a maximal response at 4 hr. No change in ornithine decarboxylase was observed in the first hour following isoproterenol administration. Rat pineal glands in organ culture responded to addition of 2 μM isoproterenol with a similar induction of N-acetyltransferase. There was a small but significant decrease in ornithine decarboxylase in the cultured rat pineal glands in response to isoproterenol. Additional experiments indicated that isoproterenol also did not elevate ornithine decarboxylase in the superior cervical ganglia under conditions known to induce tyrosine hydroxylase in this organ. The results of this study are consistent with our previous finding that ribosomal RNA synthesis is unaffected during the induction process in the pineal gland.