ADRENAL GLAND

Where is it?

Each person has two adrenal glands, one above each kidney. Each adrenal is small weighing about 15grams.

The adrenal produces four major types of hormones;

1. Glucocorticoids.- the major one is known as cortisol. Cortisol is important to maintain life and to protect against stress. One of its major functions is to raise blood glucose level by both increasing production and reducing usage. Too much cortisol can be detrimental by causing muscle wastage and depressing immunity to infection.

2. Mineralocorticoids.- the major hormone is known as aldosterone. Aldosterone ensures that adequate sodium is held in the body by ensuring that the kidney does not leak out too much salt into the urine. Aldosterone increase when upright so ensuring that the body has sufficient salty fluid to maintain blood pressure nad stop you feeling dizzy and light-headed. Likewise in dehydration, aldosterone rises to maintain salt in the body.

3. Androgen.- the most important quantitatively is dehydroepiandrosterone (DHEA) and the most potent androstenedione. DHEA remains low until puberty when a rise in production is responsible for the development of pubic and axillary hair. DHEA level rises until the third decade and then falls away with age such that at the age of 70 years it is two thirds lower. This decrease of DHEA in males is sometimes referred to as the male menopause but this is a misnomer as DHEA decreases in both males and females. The exact function of DHEA in adults is still debatable but may be implicated in maintaining muscle and bone integrity as well as general wellbeing.

4. Catecholamines.- there are two types; noradrenaline and adrenaline. These hormones are released especially in ‘flight and fright’ situations to prevent body collapse but are essential to maintain blood pressure on a daily basis.

Cortisol, aldosterone and DHEA are produced in the outer layers (known as the cortex) of the adrenal gland whilst adrenaline and noradrenaline are produced in the inner core (known as the medulla)

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Ó NHS Tayside; 2006; version 1.0

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