What releases ADH in order to increase blood pressure?

The release of antidiuretic hormone (ADH), also known as vasopressin, is primarily governed by the posterior pituitary gland. This hormone plays a crucial role in the regulation of blood pressure and fluid balance in the body.

When there is an increase in blood osmolality or a decrease in blood volume, baroreceptors and osmoreceptors stimulate the hypothalamus to synthesize ADH. The posterior pituitary then releases this hormone into the bloodstream. ADH acts on the kidneys, promoting water reabsorption in the renal collecting ducts, which helps concentrate the urine and decreases water loss from the body. By retaining water, ADH increases blood volume, which can subsequently lead to an increase in blood pressure.

In contrast, structures like the adrenal cortex, liver, and kidneys have their own distinct roles in the endocrine system and in regulating blood pressure but do not directly release ADH. The adrenal cortex is more involved in releasing hormones like aldosterone, while the liver plays a role in various metabolic processes, and the kidneys are the target organs for ADH action. However, the actual secretion of ADH itself comes solely from the posterior pituitary.