Several organs play a major role in helping the endocrine system to work well. Although these organs are not glands themselves, they do produce, store, and send out hormones that help the body to function properly and maintain a healthy balance.
Besides providing a connection between mother and fetus, the placenta is a special endocrine organ. It produces hormones that are similar to those produced elsewhere in the body. Human chorionic gonadotropin (hCG), , and are among the most important of these because they help maintain a normal pregnancy and prepare a woman's breasts for milk production and breastfeeding.
In a normal pregnancy, hCG stimulates the ovary to produce estrogens and progestins and helps stimulate normal development of the fetal genitals. The estrogens in the placenta stimulate breast development, promote normal labor, and help produce a steady rise in prolactin. The progestins stimulate breast development and help reduce uterine muscle contractions until the baby has fully developed. Human placental lactogen increases the amount of blood glucose and lipids (fatty substances) circulating in the mother's blood to ensure there is a food source for the developing baby.
The skin, liver and kidneys work together to synthesize 1,25-diydroxy vitamin D (calcitriol), the active form of , which helps maintain normal levels of calcium and phosphorus in the blood. In the skin, a molecule made from cholesterol is converted to vitamin D by exposure to ultraviolet rays from the sun. Vitamin D undergoes further chemical changes, first in the liver and then in the kidneys, to become calcitriol. Calcitriol acts on the intestine, kidneys, and bones to maintain normal levels of blood calcium and phosphorus.
Adipose tissue is typically known as body fat. Adipose tissue can be found all around the body. It is located under the skin, between muscles, and even around the organs. Adipose tissue is also an important endocrine-related organ. It contains many other cells that produce hormones as a response to signals from the rest of the body’s organs. Many other hormones are also released from adipose tissue and are responsible for different functions such as:
Having too much or too little adipose tissue can lead to other health problems. Typically, too much adipose tissue leads to obesity, which increases the risk for type 2 diabetes, high blood pressure and cholesterol, heart disease, and stroke. Too little adipose tissue can be a sign of other conditions such as lipodystrophy and anorexia.
The heart works to pump blood throughout the body through the circulatory system. The heart supplies oxygen gives nutrients to tissues and helps remove other wastes. Hormones also play an important role in maintaining healthy cardiovascular function. When blood pressure rises, the heart releases A-type natriuretic peptide and B-type natriuretic peptide. These hormones help lower blood pressure by relaxing the arterioles, which transport blood from arteries to capillaries. It also lowers blood pressure by preventing the secretion of renin and aldosterone, as well as the reabsorption of sodium ions by the kidneys. These actions reduce blood pressure by reducing the volume of blood in the circulatory system.
In addition to being required for bodily movements and participating in the regulation of body temperature, skeletal muscle commonly uptakes over 70% of glucose after a meal. After a meal, blood glucoses rises, which leads to the release of insulin. Insulin is the hormone that stimulates the uptake of glucose into skeletal muscle for energy or storage purposes. The actions of insulin result in the return of blood sugar back to normal levels. In people with type 2 diabetes, tissues such as skeletal muscle are no longer responsive to the actions of insulin, which leads to abnormally high blood sugar levels, or hyperglycemia. Another key example of endocrine function of skeletal muscle includes angiogenic factors. VEGF, for example, can act on skeletal muscle and help increase blood flow to skeletal muscle, allowing for proper oxygen, nutrient and hormone delivery to this tissue.
Severe hypoglycemia can be dangerous and must be treated promptly. It is important for patients, caregivers, providers, and the pubic to all be in the KNOW.
The Hormone Health Network is the public education affiliate of the Endocrine Society dedicated to helping both patients and doctors find information on the prevention, treatment and cure of hormone-related conditions.
All Network materials, including the content on this site, are reviewed by experts in the field of endocrinology to ensure the most balanced, accurate, and relevant information available. The information on this site and Network publications do not replace the advice of a trained healthcare provider.
Paid advertisements appear on the Hormone Health Network. Advertising participation does not influence editorial decisions or content.