METFORMIN AND METOPROLOL CR TREATMENT IN NONOBESE MEN

Objective. To study the effect of metformin and metoprolol CR on insul in sensitivity, blood lipids, fibrinolytic activity and blood pressure . Design. A double-blind, placebo controlled, triple cross-over study with randomization to either metformin, 850 mg b.i.d., or metoprolol C R 100 mg o.d., or placebo for a period of 18 weeks. The glucose uptake was measured with the euglycaemic clamp technique after every 6 weeks ' treatment period. Blood pressure and blood samples were taken every 3rd week. Subjects. Eighteen non-obese men (53+/-6 years of age). Resu lts. Metformin decreased C-peptide (P<0.02), FFA (P<0.003), total and low-density lipoprotein cholesterol, tissue plasminogen activator anti gen and the urinary potassium excretion (P<0.05 for all), but not bloo d pressure compared to placebo. Metoprolol CR reduced diastolic blood pressure and pulse rate; fasting free fatty acids and the urinary pota ssium increased (P < 0.05 for all). No effect of metformin or metoprol ol CR was seen on the glucose disposal rate, blood glucose, plasma ins ulin, triglycerides, high-density lipoprotein cholesterol, lipoprotein (a), uric acid or plasminogen activator inhibitor 1 activity or antige n. The glucose uptake was not particularly decreased in these subjects . Conclusion. The study shows that metformin has some favourable effec ts on metabolism and that metoprolol CR is fairly neutral in this rega rd. The lack of effect of metformin on glucose disposal rate and blood pressure can be explained by the fact that the individuals studied we re neither insulin resistant nor hypertensive. The data does not precl ude an antihypertensive effect by treating a concomitant insulin resis tance.