As aldosterone increases sodium uptake, a low sodium content would induce an increase in aldosterone level. This occurs through the production of intermediary substances.

A fall of plasma sodium would decrease plasma osmolality and this in turn would decrease ADH secretion. This decrease ADH secretion results in an increase in water loss and hence a decrease inplasma volume. This reduced plasma volume stimulates the granular cells of the juxtaglomerular comples. These cells in turn liberate a substance called Renin.

Renin acts on angiotensinogen, a plasma protein. Angiotensinogen is converted into angiotensin I which is in turn converted into angiotensin II in the lung tissue. Apart from acting as a vasoconstrictor, angiotensin II acts upon the adrenal gland to increase production of aldosterone.