TY - JOUR T1 - Selective Expression of CYP2A13 in Human Pancreatic α-Islet Cells JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1878 LP - 1882 DO - 10.1124/dmd.112.046359 VL - 40 IS - 10 AU - Yu Guo AU - Liang-Ru Zhu AU - Gang Lu AU - Hui Wang AU - Jun-Yan Hong Y1 - 2012/10/01 UR - http://dmd.aspetjournals.org/content/40/10/1878.abstract N2 - Exposure to cigarette smoke is an etiological factor of human pancreatic cancer and has been associated with an increased risk of pancreatic diseases, including pancreatitis and diabetes. The toxicants in cigarette smoke can reach pancreatic tissue, and most of the toxicants require cytochrome P450 (P450)-mediated metabolic activation to exert their toxicity. Among all the human P450 enzymes, CYP2A13 is the most efficient enzyme in the metabolic activation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a major tobacco-specific toxicant and a suspected human carcinogen. It also metabolically activates 4-aminobiphenyl, another toxicant in cigarette smoke. Immunohistochemical analysis in this study demonstrated that CYP2A13 was selectively expressed in the islets but not in the exocrine portion of adult human pancreas. Further study using dual immunofluorescence labeling technique showed that CYP2A13 protein was mainly expressed in the α-islet but not in β-islet cells. The selective expression of CYP2A13 in human pancreatic α-islet cells suggests that these islet cells could be damaged by the toxicants existing in cigarette smoke through CYP2A13-mediated in situ metabolic activation. Our result provides a mechanistic insight for human pancreatic diseases that have been associated with cigarette smoke exposure. ER -