Aminergic involvement in the control of luteinizing hormone secretion in the domestic fowl

Abstract

Neuropharmacologic agents have been used, in vivo, to investigate the possible involvement of the biogenic amines in the hypothalamic control of luteinizing hormone (LH) secretion in the domestic fowl. Inhibitors of norepinephrine (NE)/dopamine (DA) synthesis (for DA NE α-methyl- p-tyrosine, α-mpt; for NE diethyldithiocarbamic acid, DDC) and granule reuptake of catecholamines (reserpine) and the α-adrenergic antagonist (phenoxybenzamine) induced reductions in the circulating concentrations of LH. The administration of p-chlorophenylalanine (an inhibitor of 5-hydroxytryptamine (5HT) synthesis) and methysergide (a 5HT antagonist) also depressed plasma levels of LH. Neither β-adrenergic (propranolol) nor cholinergic (atropine) blockers affected circulating LH levels. These data suggest the involvement of a catecholamine (probably acting via α-adrenergic receptors), together with some serotoninergic components in the hypothalamic control of LH in the chicken.