John’s research in calcium metabolism spans fundamental protein biology, including the development of RIAs, protein sequencing and synthesis, mechanisms of prohormone processing, and the use of recombinant DNA tools to allow cloning of hormones and receptors. Importantly, this research has spun off clinical applications including the use of calcitonin for Paget’s disease, the use of PTH analogs for osteoporosis, the application of RIAs to distinguish primary hyperparathyroidism from humoral hypercalcemia of malignancy, and the development of long-acting forms of PTH (LA-PTH) for hypoparathyroidism.