Specific stimulation of brain serotonin mediated neurotransmission by dexfenfluramine does not restore growth hormone responsiveness in obese women
DESIGN The study had a randomized, cross-over, placebo controlled design. d-FF was administered in a dose of 15 mg twice daily during 6 days. On days 5 and 6 of treatment (with either d-FF or placebo) an i.v. bolus injection of 100 mug hGHRH(1-44) or a continuous infusion of p-galanin (40 pmol/kg/min over 40 minutes) were administered in randomized order. All tests were performed in the follicular phase of two consecutive menstrual cycles.
PATIENTS Eight obese women (body mass index (BMI) 34.5 ± 3.6 kg/m2); 7 normal weight (BMI 21.9 ± 1.9 kg/m2) age-matched control women. All women had a regular menstrual cycle. None used oral contraceptive drugs.
MEASUREMENTS GH response to either stimulus was measured both during treatment with d-FF and during treatment with placebo.
RESULTS The GH response to galanin and the response to GHRH were significantly smaller in obese subjects. d-FF significantly reduced the galanin induced GH secretion in obese subjects, but not in normal weight controls. It did not significantly affect GH release in response to GHRH in either group.
CONCLUSION This study confirms that GH secretion in response to stimuli with varying mechanisms of action is blunted in obese subjects. A decrease of central serotonin mediated neurotransmission does not appear to play a role in the pathogenesis of this phenomenon.
Document Type: Research Article
Affiliations: 1: Departments of General Internal Medicine, 2: Center for Human Drug Research, University Hospital Leiden, The Netherlands 3: Clinical Chemistry and 4: Pharmacy,
Publication date: May 1, 1996