What is the hormonal system?

The hormonal system (also called the endocrine system) has various glands that release different hormones.

Hormones are like the body’s communication system. They take messages from one part of your body (the gland) to another part of your body (the target cell).

What are endocrine glands?

Endocrine glands release hormones into your bloodstream. Your endocrine glands influence reproduction, metabolism, growth and many other functions.

You also have exocrine glands in your body — these are glands that make and release chemicals into a duct. For example, you have exocrine glands in your digestive system.

The hypothalamus and pituitary gland

The hypothalamus is an area of your brain that links your brain to your hormonal system.

The hypothalamus is connected to the pituitary gland (a small gland at the base of your brain) by a stalk.

Some of the hormones released by your hypothalamus help control your pituitary gland, also known as the ‘master gland’. The pituitary gland in turn controls many of the other endocrine glands, including your:

• thyroid gland
• adrenal glands
• ovaries
• testes

The hypothalamus and the pituitary gland also make some hormones that don’t directly act on other glands in the body.

What hormones does my hypothalamus make?

Hormones made in the hypothalamus include:

• growth hormone releasing hormone (GHRH)
• thyrotrophin releasing hormone (TRH)
• corticotrophin releasing hormone (CRH)
• gonadotrophin releasing hormone (GnRH)
• oxytocin
• vasopressin (also called anti-diuretic hormone)
• dopamine
• somatostatin

What hormones does my pituitary gland make?

Your pituitary gland makes:

• growth hormone (GH)
• thyroid stimulating hormone (TSH)
• adrenocorticotrophic hormone (ACTH)
• follicle stimulating hormone (FSH)
• luteinising hormone (LH)
• prolactin

Your pituitary gland also stores and releases some of the hormones made by your hypothalamus, including:

• oxytocin
• vasopressin

What are the other endocrine glands and what do they do?

The other endocrine glands are found in various places in your body. They release different hormones that have many different actions.

Endocrine gland	Action	Hormone(s) made
Thyroid gland	Your thyroid is a gland found in the front of your neck. Hormones made in your thyroid influence your: metabolism energy levels body temperature calcium levels	Tri-iodothyronine (T3) Thyroxine (T4) Calcitonin
Parathyroid glands	Your parathyroid glands are 4 small glands in your neck that regulate calcium levels in your blood.	Parathyroid hormone (PTH)
Adrenal glands	Your adrenal glands sit on top of your kidneys. Your adrenal glands influence your: body’s stress response blood pressure control metabolism	Adrenaline Cortisol Aldosterone Dehydroepiandrosterone (DHEA) Testosterone (in small amounts)
Pineal gland	Your pineal gland is a very small gland near the centre of your brain. It helps keep your circadian rhythm (your internal body clock).	Melatonin
Pancreas	Your pancreas is a long gland found behind your stomach, under your liver. The pancreas is an exocrine and endocrine gland. The main endocrine function of the pancreas is to control your blood sugar levels.	Insulin Glucagon Vasoactive intestinal peptide (VIP) Somatostatin
Ovaries (found in females)	Your ovaries are 2 glands found on each side of your womb. The ovaries store and release eggs and make hormones involved in puberty and reproduction.	Oestrogen Progesterone Testosterone Anti-mullerian hormone (AMH) Inhibin A and Inhibin B
Testes (found in males)	The testes are 2 glands found in the scrotum. The testes make sperm and hormones involved in puberty and reproduction.	Testosterone Anti-mullerian hormone (AMH) Estradiol Inhibin B

You can develop a medical condition if your endocrine glands make too much or not enough hormones.

There are many different causes of endocrine conditions, and treatment depends on the cause.

Resources and support

Hormones Australia has more information about your endocrine glands and the conditions that affect them.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.