Adrenal glands are present over the kidneys. These consist of the outer part known as adrenal cortex and inner part adrenal medulla. Adrenal cortex is further divided into three zones and each zone secretes certain hormones. The outermost zone is zona glomerulosa that secretes mineralocorticoids, the middle zone is zona fasciculata that secretes glucocorticoids and innermost zone is zona reticularis that secretes sex corticoids.

Aldosterone is the most important mineralocorticoid secreted. This hormone is responsible for maintenance of sodium levels in the blood. The main function is to reabsorb sodium so that its excretion is decreased. Thus if there is impairment of adrenal cortex the reabsorption will not occur and its excretion will increase and this will lower the level of sodium in blood.