TG and hypothyroidism: In addition, in vitro toxicity profile data for PCB 180 have shown weak antiestrogenic potency but moderate antiandrogenic potency [48] as well as hypothyroidism, possibly due to the reduced transport of thyroid hormones by transthyretin (TTR) and/or the induction of UDP-glucuronosyl tranferases (UGTs), the enzymes responsible for elimination of thyroid hormones [19].