Peptides, Vol. 4. pp. 50%515, 1983. ~' Ankho International Inc. Printed in the U.S.A. Presence of Vasopressin, Oxytocin and Neurophysin in the Retina of Mammals, Effect of Light and Darkness, Comparison with the Neuropeptide Content of the Neurohypophysis and the Pineal Gland' G. GAUQUELIN,* G. GEELEN,* F. LOUIS,? A. M. ALLEVARD,* C. MEUNIER,* G. CUISINAUD,§ S. BEN JANET,¶ N. G. SEIDAH,¶ M. CHRETIEN,¶ J. J. LEGROS? AND C. GHARIB* *Laboratoire de Physiologic, Facult6 de M~;decine Grange-Blanche, 69373, Lyon C~;dex 08, France "~Secteur de Neuroendocrinologie, Laboratoire de Radioimmunologie CHU Sart-Tilman-B 4000 LN'ge-Belgique §D~;partement de Physiologie et Pharmacologie Clinique, ERA CNRS 894 Facult6 de Pharmacie, 69008, Lyon ¶htstitut de Recherches Cliniques de Montr~;al, l lO Av. des Pins, Ouest, Montr~;al, Canada Received 25 January 1983 GAUQUELIN, G., G. GEELEN, F. LOUIS, A. M. ALLEVARD, C. MEUNIER, G. CU1SINAUD, S. BEN JANET, N. G. SEIDAH, M. CHRET1EN. J. J. LEGROS AND C. GHARIB. Presence ofvasopressin, oxytocin and neurophysin in the retina of'mammals, e[~'ct of' liL, ht and darkness, comparison with the neuropeptide content of the neurohypophysis and the pim'al ,ehmd. PEPTIDES 4(4) 50%515, 1983.--Arginine vasopressin (AVP) and oxytocin (OT) as well as their CNS carrier neurophysins (Np) have been found in the pineal gland. In view of the analogy between the pineal gland and the retina, the contents of these neuropeptides in rat, human and bovine retinae were determined. AVP. OT and Np were detected by specific radioimmunoassay (RIA) and their presence confirmed by RIA measurements (1) in rat and human retinae on HPLC fractions and (2) by the detection of the C-terminal portion of the precursor to AVP and its associated Np propressophysin (CPP). The AVP and OT content in the retina of the rat was modified by light: AVP and OT content was smaller at 2 a.m. than at 2 p.m.. but was increased by a 7 day constant exposure to darkness. In contrast, pituitary content was decreased after 7 days of constant darkness. If one optic nerve was cut we observed a decrease in retinal AVP content compared to the contralateral side and a decrease in pituitary AVP content. Our data clearly demonstrate the presence of AVP, OT and Np in the retina and their variation induced by light. It is probable that these peptides are of central origin. Retina Vasopressin Oxytocin Neurophysin Pineal gland Neurohypophysis Darkness APART from melatonin (and its precursors) [18, 19, 26, 27], dopamine [6] and noradrenaline [17] a wide variety of neuropeptides have been shown to exist in the retina of many vertebrates. These peptides include substance P (SP) [3, 9, 24] vasoactive intestinal polypeptide (VIP) [3,24], enkephalines [24], somatostatin [1, 3, 21-24], gas- trin/cholecystokinin (CCK) [3,4], LHRH [16] and neuroten- sin [1,24]. These neuropeptides have usually been charac- terized using immunohistochemical techniques. The pituitary peptides, arginine vasopressin (AVP) and oxytocin (OT), as well as their central nervous system car- riers, the neurophysins (Np) have now been extensively evaluated in the mammalian pineal gland [5, 7, 8]. Because of the structural similarities, however, between the cone cells ~This work was supported by Grants from the Fondation pour la Recherche M6dicale, Facult6 de Medecine Grange-Blanche (Universite CI. Bernard Lyon I) and MRC of Canada. '-'Requests for reprints should be addressed to CI. Gharib, Laboratoire de Physiologie, Facult6 de M6decine, Grange-Blanche. 8 avenue Rockefeller, 69373, Lyon C6dex 08, France. 509