Major thyroxine binding protein ?
Albumin
Prealbumin
Globulin
Transferrin
Ans. is 'c' i.e., GlobulinMost of the circulating thyroid, hormones are protein bound, leaving only 0.02% T4 and about 0.2% T3 unbound or free.There are three hormone binding plasma proteins, i.e., thyroxine binding globulin (major thyroid hormone binding protein), thyroxine binding albumin and thyroxine binding prealbumin.Thyroid binding globulin level is raised in pregnancy and by drugs estrogens, methadone, heroin, tranquilizers, clofibrate.TBG decreases by glucocoicoid, androgen, danazol, asparginase (cancer chemotherapy) and nephrotic syndrome.