Effects of short term metformin administration on androgens in normal men

OBJECTIVE: To study the effect of metformin on androgens in normal men.

METHODS: A total of 12 healthy males volunteered to participate in the study. A blood sample was obtained from each of them and analyzed for the following: Testosterone (total and free), sex hormone binding globulin dehydroepiandrosterone sulphate, 17-hydroxyprogesterone, luteinizing hormone, and follicle stimulating hormone. In addition, each participant was subjected to a glucose tolerance test and his insulin level was measured. Metformin 850 mg twice daily for 2-weeks was given to each subject after which the above tests were repeated. A paired t-test was used to assess the statistical significance of any observed differences before and after metformin.

RESULTS: After metformin administration, there was a significant reduction in serum level of total testosterone (p=0.0001), free testosterone (P=0.002), and 17 hydroxyprogesterone (p=0.0001). There was also a significant increase in serum level of sex hormone binding globulin (p=0.009) and dehydroepiandrosterone sulphate (P=0.0008). Serum levels of luteinizing hormone and follicle stimulating hormone showed no significant changes. Similarly, there were no changes in fasting plasma glucose, fasting serum insulin, weight, or blood pressure.

CONCLUSION: Metformin administration was associated with a reduction in total testosterone, free testosterone, and 17-hydroxyprogesterone and an increase in sex hormone binding globulin and dehydroepiandrosterone sulphate in normal males. The clinical significance of these findings needs further investigation.