THE INFLUENCE OF CHRONIC ADMINISTRATION OF THE SEROTONIN AGONIST DEXFENFLURAMINE ON RESPONSIVENESS TO CORTICOTROPIN-RELEASING HORMONE AND GROWTH HORMONE-RELEASING HORMONE IN MODERATELY OBESE PEOPLE

Evidence exists that the serotoninergic system influences the hypothal amo-pituitary-adrenal axis and pituitary GH secretion. The effect was investigated of chronic (9 weeks) administration of the serotonin rece ptor agonist dexfenfluramine (DF) (15 mg twice daily) versus placebo o n both systems in 24 moderately obese patients with an overconsumption of snacks. Before as well as after treatment, 100 mu g GHRH and 100 m u g CRH was administered iv. Weight loss after 9 weeks was 3.1+/-2.3 k g in the DF group and 0.1+/-1.2 in the placebo group (p<0.001). No sig nificant difference between the changes in the apparently normal ACTH and cortisol response in both groups was found. The apparently low GH response did not increase or normalize, but on the contrary decreased further after DF. No changes were shown in urinary free cortisol excre tion and serum IGF-I levels. It can be concluded that in moderately ob ese patients the use of DF during a 9-week period induced a significan t weight loss, did not influence the responsiveness of the pituitary g land to CRH nor the overall activity of the pituitary adrenal axis and finally, did not normalize the blunted GH response after GHRH.