Short-Term aerobic exercise training improves gut peptide regulation in nonalcoholic fatty liver disease

Obesity-related nonalcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease. Exercise and diet are uniformly prescribed treatments for NAFLD; however, there are limited empirical data on the effects of exercise training on metabolic function in these patients. The purpose of this study was to investigate the fasting and glucose-stimulated adaptation of gut peptides to short-Term aerobic exercise training in patients with NAFLD. Twenty-Two obese subjects, 16 with NAFLD [body mass index (BMI), 33.2 - 1.1 (SE) kg/m2] and 6 obese controls (BMI, 31.3±1.2 kg/m2), were enrolled in a supervised aerobic exercise program (60 min/day, 85% of their heart rate maximum, for 7 days). Fasting and glucose-stimulated glucagon-like peptide-1 (GLP-17-36) and peptide tyrosine tyrosine (PYYTotal) concentrations in plasma were assessed before and after the exercise program. Initially, the NAFLD group had higher fasting PYY (NAFLD±117±18.6, control±47.2±6.4 pg/ml, P<0.05) and GLP-1 (NAFLD-12.4±2.2, control-6.2±0.2 pg/ml, P<0.05) and did not significantly increase GLP-1 or PYY in response to glucose ingestion. After the exercise program, fasting GLP-1 was reduced in the NAFLD group (10.7±2.0 pg/ml, P±0.05). Furthermore, exercise training led to significant increase in the acute (0-30 min) PYY and GLP-1 responses to glucose in the NAFLD group, while the total area under the glucose-stimulated GLP-1 response curve was reduced in both NAFLD and controls (P<0.05). In summary, 7 days of vigorous aerobic exercise normalized the dynamic PYY and GLP-1 responses to nutrient stimulation and reduced the GLP-1 response in NAFLD, suggesting that exercise positively modulates gut hormone regulation in obese adults with NAFLD.