Comparative biochemistry of the pineal glands of birds and mammals

Abstract

Melatonin is synthesized from serotonin in the pineal gland by N-acetyltransferase and hydroxyindole-O-methyltransferase (HIOMT). The activities of these two enzymes have been compared in the pineal glands of rats, hamsters, chickens, and sparrows. Three different patterns of pineal biochemistry have been observed in the four species. Evidence for the regulation of pineal N-acetyltransferase activity by a noradrenergic system exists in rats but not in chickens, hamsters, and sparrows. © 1976 by the American Society of Zoologists.