London Medical Endocrinology

The word ‘adrenal’ sounds like adrenaline for a reason. Our adrenal glands produce our body’s ‘fight or flight’ hormone, adrenaline. Along with the related hormones noradrenaline and dopamine, the adrenal hormones work together to maintain our blood pressure and heart rate. But that’s not their only function. Our adrenal glands release additional hormones that are essential for healthy daily life. They are also responsible for producing steroid hormones such as cortisol and aldosterone and the androgens (male sex hormones) DHEA, androstenedione and testosterone.

You have two small triangle-shaped adrenal glands located on top of either kidney. The adrenal glands are composed of two parts: the adrenal cortex and the adrenal medulla. They each produce various hormones that impact different functions in the body. The adrenal cortex is regulated by the pituitary gland, a small, pea-sized gland located in the brain. 

What are the functions of the adrenal hormones?

The adrenal cortex is the outer part of the gland. It produces the following essential hormones:

• Cortisol helps the body respond to stress and regulates metabolism.
• Aldosterone helps control blood pressure. 
• DHEA is a male sex hormone (androgen) that is converted in the testes to testosterone.  

The adrenal medulla is the inner part of the adrenal gland. It secretes catecholamines, the hormones responsible for your body’s fight or flight response:

• Epinephrine (also called adrenaline) increases your heart rate and rushes blood to your muscles and brain, giving you a rush of strength and heightened performance in times of stress.
• Norepinephrine (also called noradrenaline) works with adrenaline to increase blood pressure, help break down fat and increase blood sugar levels to provide more energy to the body.

What might go wrong with the adrenal glands?

Adrenal disorders result from either too much of a particular hormone being secreted or not enough. This hormone imbalance might result from a problem with the adrenal glands or a problem with the pituitary gland.

If you have an adrenal problem, you might experience various symptoms depending on which hormones are affected. Commonly experienced signs and symptoms of an adrenal disorder could include:

• fatigue
• anxiety and panic attacks
• weight changes 
• changes in heart rate and blood pressure
• changes in blood sugar
• skin changes

Our adrenal experts have experience treating all types of adrenal problems. 

• Adrenal insufficiency – This is when the adrenal glands do not produce enough essential steroid hormones, which affects vital functions such as energy levels, response to illness and fluid balance. It can result from an autoimmune disease called Addison’s Disease or from a loss of pituitary function.
• Cushing’s syndrome – This condition results from an overproduction of cortisol. It is typically caused by a small tumour in the adrenal gland or on the pituitary gland (in this case, it is referred to as Cushing’s Disease).
• Hyperaldosteronism – This is when the body overproduces the hormone aldosterone, either because of a general overproduction or due to a small, usually benign tumour (this is called Conn’s syndrome). It is characterised by increased blood pressure, sodium retention and low serum potassium levels in the blood. The resulting hypertension is often referred to as endocrine hypertension.
• Adrenal cancer – This is a rare form of cancer that begins in the adrenal glands. Symptoms can be caused by the tumour secreting hormones or the large size of the tumour pressing on nearby organs.
• Congenital adrenal hyperplasia (CAH) – This genetic disorder is often first diagnosed in children. It results in excess androgenic steroids and aldosterone and too little cortisol.  
• Phaeochromocytoma – This is a type of tumour on the adrenal gland that causes too much adrenaline or other catecholamines. It can cause endocrine hypertension, a type of secondary high blood pressure caused by hormone imbalance.
• Paraganglioma – This rare neuroendocrine tumour (NET) forms near blood vessels and nerves outside the adrenal glands and can be associated with excess production of catecholamines and gut hormones.