A CHRONOBIOLOGICAL STUDY OF MELATONIN AND CORTISOL SECRETION IN DEPRESSED SUBJECTS - PLASMA MELATONIN, A BIOCHEMICAL MARKER IN MAJOR DEPRESSION

  • 1 January 1984
    • journal article
    • research article
    • Vol. 19  (8) , 1215-1228
Abstract
The temporal organization of plasma melatonin and cortisol secretion was examined in healthy rested controls and in depressed patients. Eleven patients suffering from a primary affective disorder (10 female, 1 male) and 8 male controls were studied over a 24-h period. Blood was collected at 2-h intervals during the day and at 1-h intervals at night. Plasma melatonin and cortisol levels were determined by radioimmunoassay. In addition, melatonin was determined in plasma sampled at 0300 h in older male controls (n = 8) and in females (n = 10) at ovulation. The controls showed low or undetectable (< 5 pg/ml) diurnal plasma melatonin levels and a very marked nocturnal rhythm (acrophase: 0227 h, mesor: 34.4 pg/ml, amplitude: 58.7 pg/ml). For the 3 control groups, no significant difference was observed in the nocturnal melatonin peak at 0300 h. The depressed patients also showed a significant melatonin rhythm but with lower amplitude (14.5 pg/ml) and mesor (19.1 pg/ml). The latter rhythm was not significantly phase-advanced with respect to the controls (acrophase at 0118 h and 0234 h, respectively). In 9 of the 11 patients, nocturnal melatonin secretion was less marked and frequently associated with hypercortisolemia. An additional episodic melatonin secretion was observed in the late afternoon in only 2 patients. In depressed patients, there was an increase in the mean cortisol secretion level (mesor at 13.6 .mu.g/100 ml against 9.1 .mu.g/100 ml in the controls), but the amplitude and the acrophase were not significantly modified. These data are discussed in terms of both the hypothalamus-pituitary-adrenal-epiphysis and aminergic abnormalities.