What is the function of mineralocorticoids?

Mineralocorticoids, primarily aldosterone, play a crucial role in the regulation of electrolyte and fluid balance in the body. The primary function of these hormones is to promote the reabsorption of sodium (Na+) in the kidneys. This sodium reabsorption leads to an increase in the retention of water, which helps to maintain blood volume and blood pressure. Additionally, mineralocorticoids promote the excretion of potassium (K+) from the body.

This balance of sodium and potassium is vital for various cellular functions, including maintaining the resting membrane potential and action potentials in neurons and muscle cells. The importance of this function is evident particularly in conditions where regulating blood pressure and electrolyte balance is critical, such as in heart failure or kidney disease, where mineralocorticoid activity is often altered.

The other options refer to different hormones or functions: raising blood glucose levels is associated with glucocorticoids, while peptides and proteins mentioned in the incorrect choices don't relate directly to mineralocorticoid functions.