Sex steroids affect triglyceride handling, glucose-dependent insulinotropic polypeptide, and insulin sensitivity: a 1-week randomized clinical trial in healthy young men.

OBJECTIVE

To evaluate metabolic effects of sex steroids in nonfasting and fasting conditions, independent from changes in body composition.

RESEARCH DESIGN AND METHODS

A randomized clinical trial was performed to create contrasting sex steroid levels in healthy young men: by letrozole (aromatase inhibitor) to lower estradiol (E(2)) and increase testosterone (group T, n = 10) versus letrozole plus E(2) patches to lower T and raise E(2) (group E, n = 10). Mixed meals and hyperinsulinemic-euglycemic clamps were performed before and after a 1-week treatment period.

RESULTS

Following intervention, the postprandial triglyceride response displayed a diverging response with a decline in group T and an increase in group E; the postprandial glucose-dependent insulinotropic polypeptide (GIP) response increased in group T. Insulin sensitivity increased in group T but remained unaltered in group E.

CONCLUSIONS

In healthy young men, short-term changes in sex steroids affect postprandial triglyceride and GIP response and insulin sensitivity.