Endocrinology (from the Greek endo and krino - "within to separate") is the medical specialty that deals with the effect of hormones on metabolic processes and the diseases that result from an absence or surplus of such hormones. Compared to some other fields, it's comparatively new, first coming into its own as a medical specialty when the disease diabetes mellitus was found to have been the result of the absence of the hormone insulin. Since that time, dozens of hormones have been discovered and isolated, their effect on the human body defined, and the diseases associated with such hormones identified.
Lisa Cuddy is a specialist in endocrinology.