The effects of human chorionic gonadotropin (hCG) stimulation on fat skatole concentrations and hepatic activities of cytochromes P4502E1 (CYP2E1) and P4502A (CYP2A) were studied in Landrace and Duroc breeds of entire male pigs. Pigs were divided into four groups: two control groups of each breed, without hCG stimulation (n = 20 for each breed), and two experimental groups of each breed, with hCG stimulation (n = 18 for each breed). Pigs were slaughtered 3 days after hCG stimulation and activities of CYP2E1 and CYP2A were measured in liver homogenate. Activities of both CYP2E1 and CYP2A were lower in hCG-stimulated pigs than control pigs for both Landrace (p = 0.005 for CYP2E1, p = 0.016 for CYP2A) and Duroc breeds (p = 0.003 for CYP2E1, p = 0.001 for CYP2A), and skatole concentrations in fat were higher in the hCG-stimulated pigs of both breeds (p < 0.01). For both control and hCG-stimulated groups, Duroc pigs had lower skatole concentrations than Landrace pigs (p = 0.001 for both groups). The activity of CYP2E1 did not differ significantly between breeds in either the control group or the experimental group (p = 0.233 for control pigs and p = 0.210 for experimental pigs). However, whereas CYP2A activity did not differ significantly between breeds in the control groups (p = 0.181 for CYP2A), in the hCG-stimulated groups, CYP2A activity was lower in Duroc pigs than in Landrace (p = 0.011). Based on these findings, we conclude that hCG stimulation can suppress hepatic CYP2E1 and CYP2A activities, probably through an increase in the levels of testicular steroids. Between-breed variations in skatole levels in fat were not related to the activities of CYP2E1 and CYP2A.