Which hormone acts on the distal convoluted tubules to increase water reabsorption?

The hormone that increases water reabsorption in the distal convoluted tubules is antidiuretic hormone (ADH), also known as vasopressin. ADH is secreted by the posterior pituitary gland in response to increased plasma osmolality or decreased blood volume. Its primary action occurs on the collecting ducts and distal convoluted tubules of the nephron.

When ADH is present, it promotes the insertion of aquaporin channels into the membranes of these tubules, allowing more water to be reabsorbed back into the bloodstream. This process concentrates the urine and helps to regulate body fluids, thus reducing urine volume and conserving water during times of dehydration.

In contrast, while aldosterone also plays a crucial role in regulating electrolytes and fluid balance, it primarily functions to increase sodium reabsorption and potassium excretion in the renal tubules rather than directly affecting water reabsorption. Renin is involved in the regulation of blood pressure and fluid balance but does not have a direct action on water reabsorption. Erythropoietin is primarily involved in the production of red blood cells and does not influence water reabsorption directly. Therefore, antidiuretic hormone is the correct choice for the hormone