Dr. Chopra is a Professor of Medicine at UCLA. Dr, Chopra has been a faculty member at UCLA for over 28 years beginning his stellar career as an Assistant Professor of Medicine in July 1971. He is nationally and internationally recognized for his research in thyroidology, specifically for developing radioimmunoassays for thyroxine (T4), triidothyronine (T3), and reverse triidothyronine (rT3) which have been widely used both clinically and in research. He was the first and is one of the world’s experts on the peripheral metabolism of iodothyronines. He is considered the "father of the field of thyroid hormone metabolism."