An internist who concentrates on disorders of the internal (endocrine) glands such as the thyroid and adrenal glands. The principle problems endocrinologists encounter include goiter, thyroid nodules, thyroid dysfunction, diabetes mellitus, hyper- and hypocalcemia, adrenal cortex dysfunction, endocrine hypertension, gonadal disorders, disorders of sodium and water balance, manifestations of pituitary disorders, disorders of bone metabolism, and hyperlipidemia. While not strictly an endocrine disorder, obesity is considered part of the spectrum of endocrinology because it often enters into the differential diagnosis of endocrine disease and is a major element in the management of type 2 diabetes. Prevention focuses on the complications of obesity, diabetes, hyperlipidemias, thyroid disease, and the iatrogenic effects of glucocorticoids. Endocrinologists are called on to treat problems concerning subnormal growth, early or late puberty, excess hair growth, high blood glucose or calcium levels, osteoporosis, pituitary tumors, and reproduction. They provide consultation for postoperative and chronic disease patients who require special nutritional support , and often participate in basic or clinical research.