The aim of this study is to investigate whether metformin has inhibitory effect on exercise-induced lipolysis in subcutaneous adipose tissue in healthy lean man. Ten healthy lean mean will follow protocols consisting of 60 minutes of exercise on bicycle ergometer combined with a) orally administered metformin and b) locally administered metformin into adipose tissue and c) without metformin treatment. Microdialysis is used for assessment of metabolites in situ in subcutaneous adipose tissue.

Metformin and physical activity are often recommended as the first therapeutic agents to improve glycemic control for prediabetes and type 2 diabetes (ADA). It has been reported that metformin decrease plasma concentration of non-esterified fatty acids in patients with type 2 diabetes which might be associated with the inhibition of lipolysis in adipose tissue. However, the inhibition of lipolysis during physical exercise, would not be probably beneficial. Thus, the effect of metformin on lipolysis during exercise is investigated in this protocol. As the lipolysis regulation is often impaired in obese and diabetic patients, the healthy lean men were chosen for this pilot study. Glycerol will be analyzed as a measure of lipolytic rate in adipose tissue and in plasma. Lactate levels will be observed. Our findings should provide a new background about the combination of physical activity and metformin medication.

Inclusion Criteria:

• healthy lean men, non obese, BMI 20-28 kg/m2

Exclusion Criteria:

• weight change within the 3 months before the study,
• hypertension,
• impaired fasting glucose
• diabetes
• hyperlipidemia
• drug or alcohol abuse
• smoking