The endocrine system uses hormones to control and coordinate your body's internal metabolism (or homeostasis) energy level, reproduction, growth and development, and response to injury, stress, and environmental factors. Consider the following hormones and their role in the workings of the endocrine system:
Adrenal glands | Aldosterone | Regulates salt, water balance, and blood pressure |
Adrenal glands | Corticosteroid | Controls key functions in the body; acts as an anti-inflammatory; maintains blood sugar levels, blood pressure, and muscle strength; regulates salt and water balance |
Pituitary gland | Antidiuretic hormone (vasopressin) | Affects water retention in kidneys; controls blood pressure |
Pituitary gland | Adrenocorticotropic hormone (ACTH) | Controls production of sex hormones (estrogen in women and testosterone in men) and the production of eggs in women and sperm in men. |
Pituitary gland | Growth hormone (GH) | Affects growth and development; stimulates protein production; affects fat distribution |
Pituitary gland | Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) | Controls production of sex hormones (estrogen in women and testosterone in men) and the production of eggs in women and sperm in men |
Pituitary gland | Oxytocin | Stimulates contraction of uterus and milk ducts in the breast |
Pituitary gland | Prolactin | Initiates and maintains milk production in breasts; impacts sex hormone levels |
Pituitary gland | Thyroid-stimulating hormone (TSH) | Stimulates the production and secretion of thyroid hormones |
Kidneys | Renin and angiotensin | Controls blood pressure, both directly and also by regulating aldosterone production from the adrenal glands |
Kidneys | Erythropoietin | Affects red blood cell (RBC) production |
Pancreas | Glucagon | Raises blood sugar levels |
Pancreas | Insulin | Lowers blood sugar levels; stimulates metabolism of glucose, protein, and fat |
Ovaries | Estrogen | Affects development of female sexual characteristics and reproductive development, important for functioning of uterus and breasts; also protects bone health |
Ovaries | Progesterone | Stimulates the lining of the uterus for fertilization; prepares the breasts for milk production |
Parathyroid glands | Parathyroid hormone (PTH) | Most important regulator of blood calcium levels |
Thyroid gland | Thyroid hormone | Controls metabolism; also affects growth, maturation, nervous system activity, and metabolism |
Adrenal glands | Epinephrine | Increases heart rate, oxygen intake, and blood flow |
Adrenal glands | Norepinephrine | Maintains blood pressure |
Testes (testicles) | Testosterone | Develop and maintain male sexual characteristics and maturation |
Pineal gland | Melatonin | Releases melatonin during night hours to help with sleep |
Hypothalamus | Growth hormone releasing hormone (GHRH) | Regulates growth hormone release in the pituitary gland |
Hypothalamus | Thyrotropin releasing hormone (TRH) | Regulates thyroid stimulating hormone release in the pituitary gland |
Hypothalamus | Gonadotropin releasing hormone (GnRH) | Regulates LH/FSH production in the pituitary gland |
Hypothalamus | Corticotropin releasing hormone (CRH) | Regulates adrenocorticotropin release in the pituitary gland |
Thymus | Humoral factors | Helps develop the lymphoid system |
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The thyroid is a small bow-shaped gland that sits in the front of the neck, just below the Adam’s apple. It produces the hormones:
- triiodothyronine (T3), a hormone that controls energy levels, temperature, metabolism, heart rate, blood pressure and development of a fetus
- thyroxine (T4), a hormone that controls how the heart works, metabolism, health of the muscles and bones and brain development. Some thyroxine is changed into triiodothyronine
- calcitonin, which controls the amount of calcium and phosphate in the blood
What medical conditions are related to the thyroid gland?
Almost 1 in 6 Australians has a thyroid problem. The chance of having trouble with your thyroid becomes greater as you get older.
Sometimes people have problems with their thyroid being overactive and producing too much thyroxine (hyperthyroidism). It can be caused by an autoimmune disorder causing inflammation of the thyroid gland, Grave’s disease, or nodules on the thyroid. Hyperthyroidism makes the body use energy too quickly. Symptoms of hyperthyroidism include:
- weight loss
- fatigue
- nervousness or feeling anxious
- racing heart and palpitations
- increased appetite
- losing weight
- shaking
- difficulty sleeping
- irregular periods
- infertility
- hair loss
- sensitivity to heat
In contrast, if the thyroid gland doesn’t produce enough hormones (hypothyroidism), the metabolism will reduce. This is the most common thyroid condition in Australia and is more common in men. It is often caused by the autoimmune disorder Hashimoto’s disease, but it can also be caused when the thyroid is damaged during surgery or cancer treatments.
Symptoms of hyperthyroidism include:
- being more sensitive to the cold
- fatigue
- dry skin
- brittle hair
- constipation
- weight gain
- depression
- aches and pains
- heavy or irregular periods
- looking pale
- swollen face, hands, ankles or feet
- sleep problems
- breathlessness
- difficulty getting pregnant
- an enlarged thyroid gland (goitre)
Hypothyroidism is usually permanent and is treated by replacing thyroxine.
Your doctor will be able to diagnose these problems by performing a blood test to check for the levels of thyroxine and other related hormones in your body.
If you have a problem with your thyroid, many different treatments are available. They might involve medication and, in some cases, your doctor may recommend surgery.
More information
Learn more about the endocrine system and the different hormones released by the endocrine glands.
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Last reviewed: November 2020