Endocrinology is a branch of medicine that deals with disorders of endocrine glands and hormones. Endocrine glands are located in various parts of the body and they secrete hormones directly into the blood stream. Examples of endocrine glands are Pituitary gland, Thyroid gland, Pancreas, Adrenal glands, Ovaries, Testes etc. An endocrinologist specializes in diagnosis and treatment of disorders resulting from under secretion or over secretion of these hormones.
Common diseases treated by an endocrinologist are diabetes, thyroid disorders, thyroid cancer, adrenal nodules, polycystic ovary syndrome, hypogonadism, osteoporosis, hypercalcemia, hyperparathyroidism etc.
Links:
American Diabetes Association
American Thyroid Association
American Association of Clinical Endocrinologists
National Osteoporosis Foundation