EFFECT OF AFTERNOON CLOMIPRAMINE INFUSION ON NEUROHORMONES IN DEPRESSED-PATIENTS AND NORMAL SUBJECTS

The neuroendocrine effects of afternoon intravenous infusion of clomipramine (CMI), a selective serotonin (5-HT) reuptake inhibitor, were studied in eight depressed patients and ten normal subjects. 100 ml NaCl containing 10 mg CMI were infused during 30 min in the afternoon (from 15:00 to 15:30), when the function of the hypothalamo-pituitary-adrenal system was at rest period. Blood samples were obtained 20 and 0 min before, and 30, 60, 90, 120 and 150 min after the start of the infusion. In normal subjects, CMI led to responses of significant increases in plasma ACTH, serum cortisol and serum prolactin levels, but did not in serum growth hormone (GH) levels. In depressed patients, plasma ACTH and serum cortisol responses to CMI were significantly blunted, but serum prolactin responses did not show any significant difference when compared with those in normal subjects. However, serum GH levels in depressed patients showed significant increases responses to CMI. These results suggest that the reduction in ACTH and cortisol responses in depressed patients following afternoon CMI infusion may be due to an impairment of brain 5-HT function, and that the paroxysmal increase response of GH to CMI in depressed patients may be depending upon the depressive phase.