[Isoform 1]: UDP-glucuronosyltransferase (UGT) that catalyzes phase II biotransformation reactions in which lipophilic substrates are conjugated with glucuronic acid to increase the metabolite's water solubility, thereby facilitating excretion into either the urine or bile (PubMed:12181437, PubMed:15472229, PubMed:18004206, PubMed:18004212, PubMed:18719240, PubMed:19830808, PubMed:23288867). Essential for the elimination and detoxification of drugs, xenobiotics and endogenous compounds (PubMed:12181437, PubMed:18004206, PubMed:18004212). Catalyzes the glucuronidation of endogenous estrogen hormones such as estradiol, estrone and estriol (PubMed:15472229, PubMed:18719240, PubMed:23288867). Involved in the glucuronidation of bilirubin, a degradation product occurring in the normal catabolic pathway that breaks down heme in vertebrates (PubMed:17187418, PubMed:18004206, PubMed:19830808). Also catalyzes the glucuronidation the isoflavones genistein, daidzein, glycitein, formononetin, biochanin A and prunetin, which are phytoestrogens with anticancer and cardiovascular properties (PubMed:18052087, PubMed:19545173). Involved in the glucuronidation of the AGTR1 angiotensin receptor antagonist losartan, a drug which can inhibit the effect of angiotensin II (PubMed:18674515). Involved in the biotransformation of 7-ethyl-10-hydroxycamptothecin (SN-38), the pharmacologically active metabolite of the anticancer drug irinotecan (PubMed:12181437, PubMed:18004212, PubMed:20610558).

UDP-glucuronosyltransferase (UGT) that catalyzes phase II biotransformation reactions in which lipophilic substrates are conjugated with glucuronic acid to increase the metabolite's water solubility, thereby facilitating excretion into either the urine or bile (PubMed:10702251, PubMed:15472229, PubMed:15470161, PubMed:18674515, PubMed:18719240, PubMed:19022937, PubMed:23288867, PubMed:23756265, PubMed:26220143, PubMed:17442341). Essential for the elimination and detoxification of drugs, xenobiotics and endogenous compounds (PubMed:15470161, PubMed:18674515, PubMed:23756265). Catalyzes the glucuronidation of endogenous steroid hormones such as androgens (epitestosterone, androsterone) and estrogens (estradiol, epiestradiol, estriol, catechol estrogens) (PubMed:2159463, PubMed:15472229, PubMed:18719240, PubMed:19022937, PubMed:23288867, PubMed:26220143, PubMed:17442341). Also regulates the levels of retinoic acid, a major metabolite of vitamin A involved in apoptosis, cellular growth and differentiation, and embryonic development (PubMed:10702251). Contributes to bile acid (BA) detoxification by catalyzing the glucuronidation of BA substrates, which are natural detergents for dietary lipids absorption (PubMed:23756265). Involved in the glucuronidation of the AGTR1 angiotensin receptor antagonist losartan, caderastan and zolarsatan, drugs which can inhibit the effect of angiotensin II (PubMed:18674515). Also metabolizes mycophenolate, an immunosuppressive agent (PubMed:15470161).