Metabolic Activation of Heterocyclic Amines and Expression of Xenobiotic‐Metabolizing Enzymes in the Gastrointestinal Tract of Rats

Abstract

ABSTRACT:28 Heterocyclic amines (HCAs) get entry into human body mainly through ingestion of 29 pan-fried meats cooked at high temperatures. Exposure of the gastrointestinal tract (GIT) to 30 ingested xenobiotics prior to delivery to the liver may lead to metabolic activation, which may 31 explain the high incidence of GIT carcinogenesis. Therefore, the current study investigated the 32 mutagenic activation of two heterocyclic amines, 2-aminoanthracene (2-AA) and 3-amino-1- and rectum, and it was detected at high levels in the ileum and cecum. Furthermore, we 37 revealed high metabolic activation of 2-AA and Trp-P-2 in the jejunum. The mRNA expression 38 of phase I and II enzymes in rat GIT corresponded with their mutagenic activation ability. In 39 conclusion, our results suggest that different expression levels of XME among GIT tissues may 40 contribute to the tissue-specific differences in metabolic activation of xenobiotics such as 41 heterocyclic amines in rats.