What is Endocrinology?

Endocrinology is a branch of medicine dealing with the endocrine system. The endocrine system is a complex group of glands that make different hormones. Hormones are substances that help to control various activities in your body such as metabolism (food burning and waste elimination), growth, development and reproduction. Hormones also control the way you respond to your surroundings and they help to provide proper amount of energy and nutrition your body needs to function.

The most important glands that make up the endocrine system include the pituitary, thyroid, parathyroid, pancreas, ovaries, testes, adrenal and hypothalamus.


In the original 1902 definition by Bayliss and Starling, they specified that to be classified as a hormone, a chemical must be produced by an organ or gland, be released (in small amounts) into the blood and then transported by blood to a distant organ to exert its specific function. This definition holds true for most "classical" hormones, but there are also paracrine mechanisms (chemical communication between cells within a tissue or organ), autocrine signals (a chemical that acts on the same cell) and intracrine signals (a chemical that acts within the same cell).

Endocrinology as a profession

  • An endocrinologist is a specially trained doctor. Your physician or general practitioner refers you to an endocrinologist when you have a problem such as thyroid disorders, calcium issues or adrenal problems.
  • Endocrinologists also treat patients who are overweight or obese due to metabolic or hormonal problems. Thyroid, adrenal, ovarian, and pituitary disorders can also cause obesity. Endocrinologists identify factors linked with obesity such as insulin resistance, PCOD and genetic problems.
  • Endocrinologists are also involved in research and use this experience to treat patients with hormone imbalance.


The medical specialty of endocrinology involves evaluation of a wide variety of symptoms and signs. The long-term management of endocrine disorders involves hormonal replacement for deficiency or correction of excess hormones. Most endocrine disorders are chronic diseases that need life-long care.

The diagnosis and treatment of endocrine diseases are guided by laboratory tests to a greater extent than for most specialties. Many diseases are investigated through excitation/stimulation or inhibition/suppression testing. This may involve an injection with a stimulating agent to test the function of an endocrine gland. Blood is then sampled to assess the changes of relevant hormones or metabolites. An endocrinologist needs extensive knowledge of clinical chemistry and biochemistry to understand the uses and limitations of these investigations.

A second important aspect of the practice of endocrinology is distinguishing human variation from disease. Atypical patterns of physical development and abnormal test results must be put together to come to a definite diagnosis. Diagnostic imaging of endocrine organs may reveal incidental findings called incidentalomas, which may or may not represent disease. Its our clinical task to judge the importance of such tumors and then advise an appropriate management plan.