Department of Internal Medicine III and Clinical Endocrinology, Medical Faculty, Erasmus University, Rotterdam, The Netherlands
(Received 19 November 1976)
Recently data have suggested that in man the contribution to the overall turnover of thyroxine (T4) of pathways along which this prohormone is converted either into metabolically active 3,3′,5-tri-iodothyronine (T3) or into inactive 3,3′,5′-tri-iodothyronine (reverse T3, rT3) is under physiological control. We describe here the synthesis of [125I]rT3 and the production and characterization of antisera raised against an rT 3-bovine serum albumin (rT3-BSA) conjugate.
3,3′,5′-Tri-iodo-l-thyronine-BSA, prepared essentially according to the method of Olivier, Parker, Brasfield & Parker (1968), l-rT3 and 3,3′-di-iodo-l-thyronine (3,3′-T2) were obtained by courtesy of Dr E. Scheiffele (Henning GmbH., Berlin); l-T4 and l-T3 were purchased from Sigma Chemical Co. (St Louis, Missouri, U.S.A.); 3-iodo-l-tyrosine (MIT) and 3,5-di-iodo-l-tyrosine (DIT) were obtained from Calbiochem AG (Lucerne, Switzerland); Na125I (sp.act. approximately 14 mCi/μg) from The Radiochemical Centre (Amersham) and goat anti-rabbit