Modulation of rat pineal acetyl-CoA: arylamine N-acetyltransferase induction by alpha adrenerglc drugs

The modulatory effects of alpha adrenergic drugs on the induc-tion of rat pineal acetyl-CoA:arylamine N-acetyltransferase (NAT) activity were characterized using both in vivo and organ culture techniques. lntraperitoneal administration of phenoxybenzamine (POB) to rats was followed by a 2- to 3-fold increase in activity of pineal NAT, an enzyme involved in the biosynthesis of the putative pineal hormone melatonin. The increase was greater than 60-fold when POB was administered to ganglionectomized rats. NAT induction after POB administration to ganglionectom-ized rats was not influenced by adrenalectomy, suggesting that the response to POB was not mediated through the release of catecholamines from adrenomedullary catecholamine stores. To determine whether the pharmacologic site of the activity of POB was located within the pineal body itself, pineals were incubate