title: Effect of propranolol in combination with TSH and ovine prolactin on plasma thyroid hormone levels and in vitro hepatic monodeiodination of thyroxine in brook charr, Salvelinus fontinalis (Mitchill).
abstract: 1. Ovine TSH stimulated an increase in plasma T4 levels in brook charr, but plasma T3 levels, hepatic T3 content and hepatic T4-monodeiodination to T3 were unaffected. TSH-induced plasma T4 levels were further enhanced in propranolol-pretreated fish. 2. Fish treated with ovine prolactin + TSH had elevated plasma T3 levels, hepatic T3 content and hepatic T4-monodeiodination rates compared with TSH-treated animals. Propranolol-pretreatment further enhanced hepatic T4-monodeiodination in these fish. 3. Propranolol, a beta-adrenoceptor blocker, appears to enhance peripheral T4 to T3 conversion in physiological situations when plasma thyroid hormone levels and T4-monodeiodination rates are high.
authors.affiliation: Department of Zoology, University of Guelph, Ontario, Canada.
authors.forename: J F
authors.initials: JF
authors.lastname: Leatherland
authors.forename: P A
authors.initials: PA
authors.lastname: Flett
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000008:administration & dosage; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology*; D012487:Salmonidae / Q000378:metabolism*; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000008:administration & dosage; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism; D014337:Trout / Q000378:metabolism*
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine; D011388:Prolactin; D013972:Thyrotropin; D011433:Propranolol; D013974:Thyroxine