According to the American College of Physicians: Endocrinology is the diagnosis and care of disorders of the endocrine system. The principle endocrine problems 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.
References: American College of Endocrinology