IGF-1 response to arm exercise with eccentric and concentric muscle contractions in resistance-trained athletes with left ventricular hypertrophy

摘要

The study aimed at evaluating changes in plasma levels of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), testosterone, growth hormone (GH), cortisol, and insulin in resistance-trained male athletes with (n=9) and without (n=9) left ventricular hypertrophy (LVH) in response to eccentric (ECC) and concentric (CON) arm exercise. 10 age-matched healthy non-trained subjects served as controls. M-mode and 2D Doppler echocardiography were used to estimate LV mass. Resting IGF-1 concentration was higher in LVH athletes compared to controls (52??5nM vs. 46??7nM, p0.05). ECC exercise resulted in higher (p0.05) serum IGF-1 concentrations in athletes with LVH (70??11nM, n=9) compared to those without LVH (62??10nM, n=9), and to untrained controls (54??6nM). Both CON and ECC exercise resulted in higher serum IGFBP-3 levels in LVH athletes compared to controls (242??57 and 274??58, athletes, vs. 215??63 and 244??67, controls, nM, p0.05). In ECC exercise, GH concentrations were lower in LVH than in non-LVH athletes (4.7??2.1 vs. 6.1??1.8ng??mL1, p0.05). No differences in other hormones were found between groups. In conclusion, LVH is accompanied by elevated resting serum IGF-1 and enhanced response to eccentric arm exercise. These findings suggest a role of IGF-1, possibly released from contracting muscle, in stimulating LV hypertrophy in resistance training. ? Georg Thieme Verlag KG Stuttgart ?? New York.