Which hormone causes the kidneys to conserve water?

a. tsh

b. thyroxine

c. adh

d. corticosteroids

C) ADH

ADH (Antidiuretic Hormone) The brain and kidneys regulate the amount of water excreted by the body. When the blood volume is low, the concentration of solutes in the blood is high. When the hypothalamus senses this low blood volume and increased serum osmolality it synthesizes ADH, a small peptide molecule.