Means values ± standard errors of gamma glutamyl transferase activity (GGT) in liver-soluble (A) and membrane-bound (B) fractions, expressed as pmol/min/mg prot., linear regressions established between GGT and plasma triglycerides (TG) (C); and leucyl aminopeptidase activity (LeuAP) in liver-soluble (D) and membrane-bound (E) fractions, expressed as pmol/min/mg prot. S: standard diet, VOO: virgin olive oil diet, Bch: butter plus cholesterol diet. * indicates significant differences between VOO or Bch vs. S, * p < 0.05. # indicates significant differences between VOO and Bch, # p < 0.05.