Final answer:
Aldosterone is the hormone secreted by the adrenal cortex in response to low dietary salt intake, and is part of the renin-angiotensin-aldosterone system, playing a vital role in sodium and potassium regulation.
Step-by-step explanation:
The hormone released by the adrenal cortex in response to low dietary salt intake is aldosterone. This is because aldosterone, often referred to as the "salt-retaining hormone," plays a critical role in the body's regulation of sodium (Na+) and potassium (K+) levels. It is a component of the renin-angiotensin-aldosterone system (RAAS) in which low blood volume or pressure triggers the kidneys to secrete renin.
This enzyme catalyzes the conversion of angiotensinogen to angiotensin I, which subsequently becomes angiotensin II in the lungs. Angiotensin II then stimulates the adrenal cortex to release aldosterone. As a result, aldosterone promotes Na+ reabsorption in the kidneys, as well as water retention, and increases K+ excretion.