Melatonin synthesis by the retina.
Melatonin fulfills many of the criteria for classification as a hormone. Until recently it was considered to be elaborated exclusively by pineal organs. Melatonin synthesis by other tissues has been indicated but not demonstrated unequivocally. Trout retinas in a whole-organ culture system in vitro synthesized tritiated melatonin from a substrate containing tritiated serotonin. This raises the possibility that the trout retina is an endocrine organ.
D000818:Animals; D046508:Culture Techniques; D008550:Melatonin / Q000096:biosynthesis*; D012160:Retina / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D014337:Trout
D012701:Serotonin; D008550:Melatonin