Aerobic exercise intervention (EM group) notably increased PRLR, p-JAK2, and p-STAT5 levels (P < 0.01), indicating that exercise may mitigate hepatic steatosis in NAFLD mice, likely through activation of the classical PRLR-mediated JAK2/STAT5 signaling pathway in liver. The gene discussed is STAT5B; the disease is fatty liver disease.