A short history of parathyroid hormone, its biological role, and pathophysiology of hormone excess.

Research on parathyroid hormone (PTH) over the preceding century was an exciting but sometimes confusing tale, with steady advances yet long periods of stalled progress, angry debates, and missed opportunities. There were sometimes fierce debates about the function of the parathyroids. These were finally resolved by 1925 when a potent biologic extract useful for testing in animals was finally made by Collip, and the role of PTH in calcium metabolism was established unequivocally. In the decades that followed, the pathophysiology of hormone excess (severe bone loss and other symptoms) was elucidated. Diagnosis can now be made with high reliability, even in the absence of clinical manifestation. The modern clinical profile of asymptomatic hyperparathyroidism is best described as a disorder in which there are neither signs nor symptoms traditionally associated with hypercalcemia or PTH excess.