1. What are the anatomic layers of the adrenal cortex, and which hormones do they produce?

• Zona glomerulosa: the superficial layer. Mineralocorticoid production occurs here

• Zona fasiculata: the middle layer

• Zona reticularis: the deepest layer

• The deepest two layers are for the production of glucocorticoids, androgens, and oestrogens. Progestogens are also produced, but they act mainly as precursors in the production of the other hormones

2. What is the basic composition of these hormones?

They are all steroid hormones, with a common cyclopentanoperhydrophenanthrene ring structure at the core of the molecule.

3. From which molecule are these hormones all derived?

The common source is dietary cholesterol. This is converted to another precursor, pregnenolone by enzymes of the cytochrome P450 system.

4. What are the main mineralocorticoids, glucocorticoids, androgens and oestrogens produced?

• Mineralocorticoid: Aldosterone

• Glucocorticoid: Cortisol

• Androgen: Dehydroepiandrosterone (DHEA)

• Oestrogen: Oestradiol. Only a small amount of this is secreted

5. What are the physiological effects of aldosterone?

• Sodium balance: stimulation of sodium reabsorption in the distal convoluted tubule (DCT) and collecting duct of the kidney, sweat glands, salivary glands and gut

• Potassium balance: through the active exchange with sodium ions at the membrane, leading to the loss of serum potassium

• Acid-Base balance: H+ may also be exchanged with Na+, leading to loss of H+ from the plasma. Therefore, aldosterone excess may lead to a metabolic alkalosis

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