Studies with Mouse Pituitary Thyrotropic Tumors. VI. Monodeiodination of Tetrac

SummaryI-131 labeled 3,5,3′,5′tetraiodothyroacetic acid was injected into healthy mice and into mice bearing 3 different strains of pituitary thyrotropic tumors, a pituitary adrenotropic tumor, and a fibrosarcoma. I-131 labeled 3,5,3′triiodothyroacetic acid was detected as a metabolite in the 3 thyrotropic tumors but in no other tissue. It is suggested that thyrotrope cells conduct monodeiodination of tetraiodothyroacetic acid as well as of thyroxine, and that such monodeiodination is conducted uniquely by the thyrotropes.