Exercise-induced changes in insulin action are associated with ACE gene polymorphisms in older adults

We evaluated the association between insulin resistance and the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) gene polymorphism in a group of older hypertensive subjects (63 +/- 1 yr, n = 35) before and after a 6-mo aerobic exercise program (AEX). Insulin sensitivity index (S(I)), assessed by the frequently sampled intravenous glucose tolerance test, was significantly (P = 0.0001) increased following AEX. In addition, there was a significant (P = 0.001) interaction between AEX and ACE genotype. S(I) increased significantly (P < 0.05) more in those with the II (2.5 +/- 0.8 microU x 10(-4) x min(-1) x ml(-1)) ACE genotype compared with both the DD and ID (0.7 +/- 0.1 and 0.7 +/- 0.2 microU x 10(-4) x min(-1) x ml(-1), respectively) ACE genotypes. Similarly, there was a significant (P = 0.036) decrease in the acute insulin response to glucose (AIR(G)) and a significant (P = 0.05) interaction between AEX and ACE genotype. AIR(G) decreased significantly (P < 0.05) more in those with the II (-17.6 +/- 5.6 mU/ml) ACE genotype compared with both the DD and ID (-1.4 +/- 6.2 and -3.6 +/- 2.5 mU/ml) ACE genotypes. In conclusion, we demonstrated that those older hypertensives with the ACE II genotype have the greatest improvement in insulin action following AEX.