Endocrinology is the branch of medicine that deals with the hormone-secreting glands (ex: thyroid, pituitary, adrenal, pancreas, ovaries, testes, etc.); also deals with diabetes. Endocrinology refers to the endocrine system - a collection of hormone-producing glands which regulate the body's rate of metabolism, growth and reproductive development and functioning. An increase or decrease in production interferes with the process it controls. Examples of problems include thyroid conditions and diabetes.