Which hormone is key for vascular constriction in addition to water reabsorption?

Antidiuretic hormone (ADH), also known as vasopressin, plays a crucial role in both water reabsorption and vascular constriction. It is produced in the hypothalamus and released from the posterior pituitary gland.

When present in the bloodstream, ADH promotes the reabsorption of water in the kidneys, specifically in the collecting ducts. This process leads to a decrease in urine volume and helps maintain fluid balance and blood pressure. Additionally, ADH can cause blood vessels to constrict, which increases vascular resistance and elevates blood pressure. This dual role is vital, especially in situations where the body needs to retain water and manage blood pressure simultaneously, such as during dehydration or significant blood loss.

In contrast, other hormones listed do not have the same combination of functions. Insulin primarily regulates glucose levels, adrenaline is more focused on "fight or flight" responses and increasing heart rate, whereas cortisol is involved in stress responses and metabolism but does not directly contribute to vascular constriction in the same way ADH does.