Question

Why are renin levels increased during fluid deficit?

Answer 1

Renin levels are increased during fluid deficit as renin acting as an enzyme converts angiotensinogen to angiotensin 1 which is then converted to angiotensin 2 and this acts directly on the kidney tubules to increase sodium reabsorption and release aldosterone. The aldosterone works in the distal tubule of the kidney to promote the exchange of sodium and potassium, sodium is reabsorbed and potassium is lost which brings water with it resulting in an increase in circulating blood volume. This helps in restoring the fluid levels when there is a fluid deficit.