Part of that extra thickness is caused by the protein keratin, which is nourished in deeper layers of the skin but forms a surface layer of dead cells on the epidermis. This extra thickness may also explain why your hands and feet become wrinkled when you soak in the tub.
Antidiuretic hormone (ADH), also called arginine vasopressin (AVP), is a hormone that helps regulate water balance in the body by controlling the amount of water the kidneys reabsorb while they are filtering wastes out of the blood. This test measures the amount of ADH in the blood.
ADH is also called arginine vasopressin. It is a water-regulating hormone made by the hypothalamus (in the brain), and stored in the posterior pituitary gland. ADH is the chemical that tells the kidneys how much water to conserve. ADH constantly regulates and balances the amount of water in the blood. Higher water concentration increases the volume and pressure of the blood. Osmotic sensors and baroreceptors work in tandem with ADH to maintain water metabolism.