I-Melatonin yihomoni ekhutshwe yi-pineal gland yobuchopho kwizilwanyana ezanyisayo nakubantu.Kuba inokwenza iiseli ezivelisa imelanin ukukhanya, kungoko igama elithi melatonin, ekwabizwa ngokuba yipineal hormone, melatonin, melatonin.Emva kokuba i-melatonin yenziwe yaza yagcinwa kumzimba wepineal, ukuvuseleleka kwemithambo-luvo kugcina iiseli zepineal zikhuphe imelatonin.Ukukhutshwa kwe-melatonin kunesingqisho esicacileyo se-circadian, esicinezelwa emini kwaye sisebenze ebusuku.I-Melatonin inokuthintela i-hypothalamic-pituitary-gonadal axis, ukunciphisa umxholo we-gonadotropin ekhupha ihomoni, i-gonadotropin, i-hormone ye-luteinizing kunye ne-follicle evuselela i-hormone, kwaye ingenza ngokuthe ngqo kwi-gonads ukunciphisa umxholo we-androgen, i-estrogen kunye ne-progesterone.