This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine System, Subject name: Physiology
Thyroxine binding globulin (TBG) is increased in: 
Select and explain. 
A. Glucocoicoid therapy, B. Nephrotic syndrome, C. Pregnancy, D. Cancer chemotherapy
C: Pregnancy
Answer: C: Pregnancy 
Explanation: TBG concentration increases in (conditions of high estrogen levels) such as: pregnancy oral contraceptives. TBG concentration is decreased by: Hormones ( androgens, glucocoicoids;) Malnutrition nephrotic syndrome cancer chemotherapy. Drugs, such as phenytoin, salicylates.