Dysregulation of plasma pro-opiomelanocortin-related peptides in neurotic depression.
In order to assess whether a central hypothalamic impairment could account for the pro-opiomelanocortin (POMC)-related peptide over-secretion in depressive disorders, plasma B-lipotropin (B-LPH), B-endorphin (B-EP) and cortisol concentrations were measured in 9 patients affected by neurotic depression: every 4 h over a 24-h period; in response to insulin-induced hypoglycaemia (0.1 IU/kg body weight), and during dexamethasone (DXM) administration (0.5 mg X 4/day for 2 days). Eight age-matched healthy volunteers (controls) were also studied. B-EP and B-LPH were determined by specific radioimmunoassays after plasma extraction and gel chromatography. Compared with the controls, the patients showed a 3 times higher plasma B-EP, twice the normal B-LPH levels, and a 20% cortisol increase. The neurotic depressed patients showed and evening-related decrease in the levels of the 3 hormones, expressed as mean values, similar to that in the controls, whereas the single cosinor analysis revealed a significant circadian rhythm of B-LPH and B-EP only in 3 and 2 patients, respectively. Insulin-induced hypoglycaemia (ITT) stimulated the release of B-LPH and cortisol in both groups, whereas the B-EP increase was absent in the patients. DXM reduced plasma cortisol and B-LPH levels in controls and patients, but in the latter it failed to reduce the B-EP concentrations. The present data indicate that neurotic depressed patients are characterized by increased activity of the hypothalamic-pituitary-adrenal axis, with maintained circadian rhythmicity.(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002940:Circadian Rhythm; D003866:Depressive Disorder / Q000097:blood*; D003907:Dexamethasone / Q000494:pharmacology; D004723:Endorphins / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011333:Pro-Opiomelanocortin / Q000097:blood*; D001615:beta-Endorphin; D008083:beta-Lipotropin / Q000097:blood*
D001786:Blood Glucose; D004723:Endorphins; D007328:Insulin; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D003907:Dexamethasone; D008083:beta-Lipotropin; D006854:Hydrocortisone