Plasma melatonin levels in affective states

Abstract

Melatonin is a major endocrine product of the pineal gland. It is produced at night when noradrenaline acts on beta-adrenergic receptors to stimulate enzymes which catalyse the formation of melatonin from serotonin. It is believed by some that nocturnal melatonin levels reflect beta-receptor function. The melatonin rhythm is also thought to be an indication of circadian rhythmicity. The nocturnal production of melatonin was studied in patients with depression and panic disorder and in control subjects. Midnight concentrations of melatonin in eleven depressed patients were significantly lower than 18 control subjects (27.1 +/- 5.1 pg/ml compared with 51.6 +/- 4.1 pg/ml; p less than 0.02, t-te..