Final answer:
The hormone primarily responsible for water retention is antidiuretic hormone (ADH), and progesterone can also bind to aldosterone receptors, contributing to water retention.
Step-by-step explanation:
The hormone responsible for water retention in the body is known as antidiuretic hormone (ADH), or vasopressin. ADH acts on the kidneys to promote water reabsorption from the collecting ducts, thus reducing urine volume and helping to conserve water in the body. Furthermore, progesterone can bind to receptors for aldosterone, a hormone that, when released, also promotes water retention by increasing sodium reabsorption in the kidneys, which in turn leads to water retention due to the osmotic movement of water back into the bloodstream.
Aldosterone is released in response to the hormone angiotensin II, which is part of the renin-angiotensin system, a crucial regulator of blood pressure and fluid balance. While progesterone is structurally similar to aldosterone and can thus bind to the same receptor, it usually provides a milder effect compared to aldosterone itself.