title: Propranolol inhibits the in vitro conversion of thyroxine into triiodothyronine by isolated rat liver parenchymal cells.
abstract: A model for the in vitro study of the conversion of thyroxine into triiodothyronine using isolated rat liver parenchymal cells is described. Isolated liver cells (mean protein content 18 mg/ml) convert approximately 0.8% of 1.3 microM exogenously added T4 into T3 during thirty minutes incubation. Carbimazole (50 microM) has no effect on the conversion process, whereas propylthiouracil (50 microM) inhibits the conversion. The beta-adrenoceptor blocking agent propranolol lowers the conversion ratio when added in concentrations of 580 and 1160 microM, but has no inhibitory effect when 290 microM is added.
mesh_terms: D000818:Animals; D002231:Carbimazole / Q000494:pharmacology; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011433:Propranolol / Q000494:pharmacology*; D011441:Propylthiouracil / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000096:biosynthesis*
chemical_list: D014284:Triiodothyronine; D011441:Propylthiouracil; D002231:Carbimazole; D011433:Propranolol; D013974:Thyroxine