What hormone inserts aquaporins into the distal convoluted tubule and collecting ducts in the kidney?

The correct answer is C, which identifies antidiuretic hormone (ADH) as the hormone responsible for inserting aquaporins into the distal convoluted tubule and collecting ducts in the kidney. This process is crucial for regulating water reabsorption in the body.

ADH, also known as vasopressin, is released from the posterior pituitary gland in response to increased plasma osmolality or decreased blood volume. When ADH reaches the kidneys, it promotes the insertion of aquaporin-2 channels into the apical membranes of the epithelial cells of the distal convoluted tubule and collecting ducts. This insertion enhances the permeability of these segments of the nephron to water, allowing for increased water reabsorption back into the bloodstream, thereby concentrating the urine and reducing water loss.

In the absence of ADH, aquaporins are not present in these tubules, leading to decreased water reabsorption, more dilute urine, and potential dehydration. This process is vital for maintaining the body's fluid balance and is a key regulatory mechanism in the kidneys.

The other hormones mentioned, while they play important roles in renal function and fluid balance, do not specifically insert aquaporins in this manner. For example, aldosterone primarily regulates