Immunocytochemical evidence for the presence of arginine vasotocin in the Rat pineal gland

THE discovery that the pineal gland contained melatonin¹ provided the stimulus for a multidisciplinary approach to the study of this organ. Considerable evidence suggests that this gland affects reproductive physiology. For example, it contains biologically active polypeptides. One of the first of these to be identified was arginine vasotocin (AVT), initially isolated from extracts of bovine pineal gland², and later identified chemically and found to have antigonadotropic properties^3,4. There is physiological and radioimmunoassay evidence for the origin of AVT in the pineal gland. We now present immunocytochemical evidence for the presence of this polypeptide in the pineal gland.