Effect of exercise intensity on circulating hepatokine concentrations in healthy men

Fibroblast growth factor 21 (FGF21), follistatin and leukocyte cell-derived chemotaxin 2 (LECT2) are novel hepatokines that are modulated by metabolic stresses. This study investigated whether exercise intensity modulates the hepatokine response to acute exercise. Ten young, healthy men undertook three 8-h experimental trials: moderate-intensity exercise (MOD; 55% peak oxygen uptake), high-intensity exercise (HIGH; 75% peak oxygen uptake), and control (CON; rest), in a randomised, counterbalanced order. Exercise trials commenced with a treadmill run of varied duration to match gross exercise energy expenditure between trials (MOD vs HIGH; 2475 +/- 70 vs 2488 +/- 58 kJ). Circulating FGF21, follistatin, LECT2, glucagon, insulin, glucose and nonesterified fatty acids (NEFA) were measured before exercise and at 0, 1, 2, 4, and 7 h postexercise. Plasma FGF21 concentrations were increased up to 4 h postexercise compared with CON (P <= 0.022) with greater increases observed at 1, 2, and 4 h postexercise during HIGH versus MOD (P <= 0.025). Irrespective of intensity (P >= 0.606), plasma follistatin concentrations were elevated at 4 and 7 h postexercise (P <= 0.053). Plasma LECT2 concentrations were increased immediately postexercise (P <= 0.046) but were not significant after correcting for plasma volume shifts. Plasma glucagon (1 h; P = 0.032) and NEFA (4 and 7 h; P <= 0.029) responses to exercise were accentuated in HIGH versus MOD. These findings demonstrate that acute exercise augments circulating FGF21 and follistatin. Exercise-induced changes in FGF21 are intensity-dependent and may support the greater metabolic benefit of high-intensity exercise.