THYROIDVolume 5, Number 6, 1995Mary Ann Liebert, Inc.

LATS Prize Lecture

Dr. J. Enrique Silva was born and raised in Santiago, Chileand graduated from the University of Chile School ofMedicine in Santiago. At the outset of his scientific career, hedemonstrated an interest in thyroid research, specifically in io¬dine deficiency. In 1974 Enrique came to the United States totrain with Dr. Jack H. Oppenheimer in Minneapolis and, notsurprisingly, he developed an interest in thyroid hormone ac¬tion. He completed his training with Dr. P. Reed Larsen inBoston where he studied the regulation of TSH secretion by T3and T4. This work indicated for the first time the existence ofa distinct 5'-deiodinase, which was later shown by Silva andLarsen to be Type II 5'-deiodinase.After returning to Chile for a few years, he immigrated to

the United States and was appointed to the Faculty of HarvardMedical School. His efforts were concentrated on the metabo¬lism and action of thyroid hormone in the brain. These studies

demonstrated that the concentration of T3 in the brain is largelycontrolled by local mechanisms acting upon the Type II 5'-deiodinase and the degradation of T3. These studies showedthat the brain had a great capacity to adapt to low T4 concen¬trations and provided an explanation as to why endemic cre¬

tinism is not very frequent, except in areas with profound io¬dine deficiency where levels of fetal thyroxine are extremelylow. Largely because of this work, Dr. Silva was awarded theVan Meter-Armour Award of the American ThyroidAssociation in 1983.After another seminal paper in Nature in 1983 showing that

the Type II deiodinase of brown adipose tissue was stimulatedby the sympathetic nervous system, Dr. Silva focused his re¬search on the role of thyroid hormone on the regulation of ther¬mogenesis and energy balance. He and his colleagues havedemonstrated that the T3 generated by the Type II 5'-deiodi¬nase in brown fat is essential for the function of this tissue.More recently, he has shown that the sympathetic nervous sys¬tem and thyroid hormone interact synergistically in this tissue,thus forming a powerful model to understand thyroid hormoneadrenergic relationships. Dr. Silva presented this work in hisaddress at the 11th International Thyroid Congress. For thiswork as well for his continued support of thyroid research inSouth America, notably his fostering of numerous young in¬vestigators from that continent, Dr. Silva was awarded the 1995Lecture Prize of the Latin American Thyroid Society at the 11thInternational Thyroid Congress.In 1991 Dr. Silva moved to McGill University and the Jewish

General Hospital in Montreal, Canada, where he is Chief ofEndocrinology and Professor of Medicine. He is also a mem¬

ber of the Metabolism and Nutrition Committee of the MedicalResearch Council of Canada.

Joao H. RomaldiniPresident, LATS

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