Effects 2-Aminoanthracene Exposure on Insr, Irs, Akt and Glut4 Expression

The modulation of the toxic effects of 2-aminoanthracene (2AA) on the expression of insulin receptor (Insr), insulin receptor substrate (Irs1), v-akt murine thymoma viral oncogene homolog 1 (Akt1) and solute carrier family2, facilitated glucose transporter member 4 (Glut4) liver is being investigated. These genes play vital roles including regulatory activity in insulin signaling and glucose metabolism (Akt1), important glucose transporter essential for the development of type 2 diabetes (Glut4) and activation and processing of insulin signaling transduction (Insr, Irs). In a previous study to assess the toxic effects of 2AA using global gene expression coupled with DAVID bioinformatics tool, it was found that several genes that regulate the insulin signaling pathway may be altered by 2AA toxicity. The objective of the current investigation is to examine the mRNA expression of four specific genes that mediate insulin signaling due to 2AA toxicity. Polynuclear aromatic amine, 2AA is a by-product of cigarette smoke and broiled meat. Twenty four post-weaning 3-4 week old F-344 male rats were exposed to 0 mg/kg-diet (control), 50 mg/kg-diet (Low Dose - LD), 75 mg/kg-diet (medium dose - MD) and 100 mg/kg-diet (high dose - HD) 2-AA for 2wks and 4wks. The mRNA expression of Insr, Irs1, Akt1 and Glut4 was determined by quantitative real-time PCR followed by the quantification of Akt1 via enzyme-linked immunosorbent assay (ELISA) assay. Transcripts Glut4 and Insr were not expressed at all in all treatment groups. Akt1 gene was up-regulated in animals treated to 2AA for both two and four weeks. Similarly, Irs1 mRNA was only up-regulated in rats that ingested 2AA for four weeks. It appears Akt1 and Irs1 proteins were targets of 2AA intoxication. This study is still ongoing to quantify the level of protein expression of Akt1 in the livers of rats exposed to 2AA