Circulating melatonin in man: episodic secretion throughout the light-dark cycle.
A sensitive and specific RIA for melatonin has been validated for human plasma. Five young adult men had plasma samples obtained every 20 min during two 24-h periods. One was a normal active period and the other a basal period with complete bed rest. Melatonin was found to be secreted episodically throughout the 24 h in each condition, with secretory episodes clearly present during the waking day in the presence of bright light.
D000328:Adult; D002940:Circadian Rhythm; D003624:Darkness; D006801:Humans; D008027:Light; D008297:Male; D008550:Melatonin / Q000097:blood*; D011863:Radioimmunoassay
D008550:Melatonin