Aldosterone

Aldosterone release is dependent upon two primary stimuli. Both an increase in angiotensin II concentration, and an increase in plasma [K+] lead to the release of aldosterone into the circulation. Although the half-life of aldosterone is only twenty minutes, its action peaks about thirty minutes after release due to the production of proteins and an increase in the number of channels present. For a more detailed discussion of the relationship between renin, angiotensin, and aldosterone, please see the renin page.

From this explanation of the physiological effects of renin, you should be able to understand the consequences involved with hypo- and hyperaldosteronism. Hypoaldosteronism will result in decreased sodium uptake in the collecting ducts, causing a decrease in ECV. This leads to an increase in sympathetic tone, and increased concentrations of renin, angiotensin II, and ADH. Hyperaldosteronism will show the opposite effects.

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