Enteral Infusion of Green Tea Extract Selectively Enhances the Biliary Secretion of ∨14C-Benzo[a]pyrene in Rats without Affecting Other Biliary Lipids
2011
Noh, S.K., Changwon National University, Changwon, Republic of Korea | Kim, J.Y., Changwon National University, Changwon, Republic of Korea
Recently, we have demonstrated that green tea extract (GTE) decreases the intestinal absorption of benzo[a]pyrene (BAP), which is an extremely lipophilic food contaminant. The present study was conducted to examine if an enteral infusion of GTE would influence the biliary secretion of BAP and lipids in rats. Female rats were fed an AIN-93G diet with or without (control) GTE at 5 g/kg diet for 4 week. Following the 4-week dietary treatment, rats with bile duct cannula were infused continuously for 8 hr at 3.0 mL/hr via a duodenal catheter with a lipid emulsion containing 4.0 μmol BAP labeled with ∨14C (∨14C-BAP), 20.7 μmol cholesterol, 452 μmol triolein, and 3.1 μmol α-tocopherol, and 396.0 μmol Na-taurocholate with or without 76.1 mg GTE powder in PBS buffer (pH, 6.4). Bile was collected hourly via bile cannula for an 8 hr period. Our results showed that bile flow did not differ between groups. However, the biliary secretion of ∨14C-BAP was significantly enhanced by GTE infusion, compared with those infused with the lipid emulsion alone. However, GTE did not affect the biliary outputs of cholesterol, fat, phospholipid and α-tocopherol. These findings indicate that GTE has a profound stimulatory effect on the biliary excretion of BAP in rats, without affecting other biliary lipids. The mechanism(s) by which GTE enhances the biliary secretion of BAP remains to be investigated.
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