Influence of melatonin administration on glucose tolerance and insulin sensitivity of postmenopausal women. Cagnacci A, Arangino S, Renzi A, Paoletti AM, Melis GB, Cagnacci P, Volpe A. Institute of Obstetrics and Gynaecology of Modena, Modena, Italy. cagnacci@unimo.it OBJECTIVE: The effect of melatonin on human carbohydrate metabolism is not yet clear. We investigated whether melatonin influences glucose tolerance and insulin sensitivity in aged women. PATIENTS: Twenty-two postmenopausal women of whom 14 were on hormone replacement therapy. DESIGN: After an overnight fast, at 0800 hours on two nonconsecutive days, placebo or melatonin (1 mg) were administered randomly and in a double blind fashion. Forty-five minutes later, an oral glucose tolerance test (75 g; OGTT) was performed in 13 women. In another nine women insulin-dependent (Si) and -independent (Sg) glucose utilization was tested by a frequently sampled intravenous glucose tolerance test (FSIGT). RESULTS: Areas under the response curve to OGTT (AUC) for glucose (1420 +/- 59 vs. 1250 +/- 55 mmol x min/l; P < 0.01), and C-peptide (42,0980 +/- 45,320 vs. 33,528 +/- 15,779 pmol x min/l; P < 0.02) were higher following melatonin than placebo, while Si values were lower (2.6 +/- 0.28 units vs. 3.49 +/- 0.4 units; P < 0.03). Si modifications induced by melatonin were inversely related to Si values of the placebo day (r(2) = 0.538; P < 0.025). CONCLUSIONS: The present results indicate that in aged women administration of 1 mg of melatonin reduces glucose tolerance and insulin sensitivity. The present data may have both physiological and clinical implications. Clin Endocrinol (Oxf) 2001 Mar;54(3):339-46 Publication Types: Clinical Trial Randomized Controlled Trial PMID: 11298086 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.