Irinotecan is widely used in the treatment of solid tumors, especially in colorectal cancer and lung cancer. Molecular testing for UGT1A1 genotyping is increasingly required in China for optimum irinotecan administration. In order to determine the performance of laboratories with regard to the whole testing process for UGT1A1 to ensure the consistency and accuracy of the test results, the Natio...

Background: FOLFIRI regimen, which is composed of 5-FU, Leucovorin, and Irinotecan, is used in the first-line chemotherapy of metastatic colorectal cancer. Irinotecan life threatening toxicity is partly related to cytotoxic drug metabolite which is primarily inactivated by the UGT1A1 enzyme. The primary aim of the present research was to find the correlation between UGT1A1-genotype and clinical...

Humanized mice that express the human UDP-glucuronosyltransferase (UGT) 1 locus have been developed in a Ugt1-null background as a model to improve predictions of human UGT1A-dependent drug clearance. Enzyme kinetic parameters (K(m) and V(max)) and pharmacokinetic properties of three probe drugs were compared using wild-type and humanized UGT1 mice that express the Gilbert's UGT1A1*28 allele [T...

The human UDP-glucuronosyltransferase (UGT) 1A (UGT1A) locus is regulated in a tissue specific fashion in liver and extrahepatic tissues. Three extrahepatic UGT1A proteins, UGT1A7, UGT1A8, and UGT1A10, have been discovered and are believed to contribute to the diversity of extrahepatic glucuronidation. UGTs eliminate by glucuronidation a broad variety of endobiotic and xenobiotic substrates, wh...

Well-done cooked protein containing foods derived from muscle can contain 1–200 parts per billion of mutagenic/carcinogenic heterocyclic amines. The most abundant of these compounds, 1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridin-2-amine (PhIP), has recently been classified by the National Toxicology Program (NTP) to be ‘‘a reasonably anticipated human carcinogen.’’ This is in part because of the e...

The co-ordinated induction of several hepatic drug-metabolizing enzymes is a common feature in the regulation of drug biotransformation under normal and pathological conditions. In the present study the activity and expression of bilirubin UDP-glucuronosyltransferase (UGT1A1) were investigated in livers of BioBreeding/Worcester diabetic, fasted and acetone-treated rats. Bilirubin glucuronidatio...

We develop a strategy for haplotype analysis of PCR products that contained two adjacent heterozygous loci using sequencing with specific primers, allele-specific primers, and ddNTP-blocked primers. To validate its feasibility, two sets of PCR products, including two adjacent heterozygous SNPs, UGT1A1⁎6 (rs4148323) and UGT1A1⁎28 (rs8175347), and two adjacent heterozygous SNPs, K1637K (rs1117601...

Many phase I and II enzymes are under hormonal regulation, resulting in sex-related expression patterns. This sex-related enzyme expression can result in differential metabolism of physiologically active endogenous substances, altered xenobiotic clearance, and differences in susceptibility to drug toxicities. Treatment of female Sprague-Dawley (SD) rats with 5 mg testosterone propionate/kg/day,...

A metabolite formed by incubation of human liver microsomes, etoposide, and UDP-glucuronic acid was identified as etoposide glucuronide by liquid chromatography-tandem mass spectrometry analysis. According to the derivatization with trimethylsilylimidazole (Tri-Sil-Z), it was confirmed that the glucuronic acid is linked to an alcoholic hydroxyl group of etoposide and not to a phenolic group. Am...

The anticancer prodrug, irinotecan, is converted to its active form 7-ethyl-10-hydroxycamptothecin (SN-38) by carboxylesterases, and SN-38 is inactivated by UDP-glucuronosyltransferase (UGT)1A1-mediated glucuronidation. UGT1A9 also mediates this reaction. In a recent study, it was reported that the UGT1A9 IVS1+399 (I399)C>T polymorphism is associated with increased SN-38 glucuronidation both in...