Center and a residency at the Boston City Hospital. In 1956 he joined the laboratory of Ted Astwood as a research fellow at Tufts Medical School, where he was able to continue his studies on parathyroid hormone. This area of research occupied most of his research career. At that time only a few polypeptide hormones had been characterized. It was known that injection of an extract of parathyroid glands into test animals raised calcium levels in the blood, but the nature of the active substance was not known. Many investigators had already tried to purify this factor without success. Gerry thought of the novel idea of using phenol extraction to remove the hormone from proteins with which it was associated and to inactivate proteases causing its degradation. This approach was very successful and a paper published in 1959 established Gerry as the leader in the field.
Despite his early success Gerry felt he needed further training in research and applied to a new, prestigious training program at the National Institutes of Health in Bethesda, Maryland. Gerry was selected for the Research Associate Training Program and in 1959 joined the laboratory of William Jakoby, where he received training in enzyme biochemistry. In 1961 he accepted a research associate position in the Metabolic Diseases Branch of the National Institute of Arthritis and Metabolic Diseases and established his own research group. He spent his entire career in the branch, eventually becoming its chief in 1973.
When Gerry started his own laboratory, he returned to the parathyroid hormone field. His first goal was to obtain sufficient amounts of highly purified protein to determine its sequence. This was a challenging problem because the amount of hormone in each parathyroid is very low; parathyroid glands are small and protein purification techniques were in their infancy. Aurbach and colleagues were able to overcome these obstacles and they obtained sufficient