What is the primary function of angiotensin II in the body?

The primary function of angiotensin II in the body is to increase blood pressure. This peptide hormone plays a crucial role in the regulation of blood pressure and fluid balance. It does so through several mechanisms: it causes blood vessels to constrict, which increases the resistance the heart must work against, thereby raising blood pressure. Additionally, angiotensin II stimulates the release of aldosterone from the adrenal glands, which promotes sodium and water retention by the kidneys. This retention further contributes to increased blood volume, enhancing blood pressure.

While other options reference important physiological functions, they do not relate to the primary role of angiotensin II. Lowering blood sugar levels is primarily regulated by insulin and other hormones. Tissue repair is more associated with growth factors and wound healing processes. Appetite stimulation typically involves hormones related to hunger signals, such as ghrelin and leptin.