Which hormone system do kidneys utilize for blood pressure regulation?

The kidneys utilize the renin-angiotensin-aldosterone system (RAAS) for blood pressure regulation, which is crucial for maintaining fluid balance and systemic blood pressure. When blood pressure drops, the kidneys sense this change and release an enzyme called renin. Renin then converts angiotensinogen, a protein produced by the liver, into angiotensin I. This substance is further transformed into angiotensin II by angiotensin-converting enzyme (ACE), primarily in the lungs.

Angiotensin II is a powerful vasoconstrictor, which means it narrows blood vessels, thereby increasing blood pressure. Additionally, it stimulates the secretion of aldosterone from the adrenal cortex, which prompts the kidneys to retain sodium and water, further contributing to increased blood volume and pressure. The overall effect of this system is to restore blood pressure to normal levels through a combination of vascular resistance and fluid retention.

In contrast, the HPA axis primarily involves the interaction between the hypothalamus, pituitary gland, and adrenal gland, mainly influencing stress responses rather than directly regulating blood pressure. The insulin signaling pathway is focused on glucose metabolism and does not play a role in blood pressure regulation. Lastly, the gastric regulation system deals with digestive processes,