Serum IGF-I and hormonal responses to incremental exercise in athletes with and without left ventricular hypertrophy

We investigated the response of insulin-like growth factor (igfi),insulin-like growth factor binding protein-3 (igfbp-3) andsome hormones, i.e., testosterone (t), growth hormone (gh),cortisol (c), and insulin (i), to maximal exercise in road cyclistswith and without diagnosed left ventricular hypertrophy. mmodeand two-dimensional doppler echocardiography wasperformed in 30 professional male endurance athletes and agroup of 14 healthy untrained subjects using a hewlett-packardimage point hx ultrasound system with standard imaging transducers.echocardiography and an incremental physical exercisetest were performed during the competitive season. venousblood samples were drawn before and immediately after themaximal cycling exercise test for determination of somatomedinand hormonal concentrations. the basal concentration of igf-iwas statistically higher (p < 0.05) in athletes with left ventricularmuscle hypertrophy (lvh) when compared to athletes with anormal upper limit of the left ventricular wall (lvn) (p < 0.05)and to the control group (cg) (p < 0.01). the igf-i level increasedsignificantly at maximal intensity of incremental exercisein cg (p < 0.01), lvn (p < 0.05) and lvh (p < 0.05)compared to respective values at rest. long-term endurancetraining induced an increase in resting (p < 0.01) and postexercise(p < 0.05) igf-i/igfbp-3 ratio in athletes with lvhcompared to lvn. the testosterone (t) level was lower in lvhat rest compared to lvn and cg groups (p < 0.05). these resultsindicate that resting serum igf-i concentration were higherin trained subjects with lvh compared to athletes withoutlvh. serum igf-i/igfbp-3 elevation at rest and after exercisemight suggest that igf-i act as a potent stimulant of left ventricularhypertrophy in chronically trained endurance athletes.