Which hormone is related to the body's water balance and is not secreted by the anterior pituitary?

The hormone that plays a crucial role in regulating the body's water balance and is not secreted by the anterior pituitary is anti-diuretic hormone (ADH), also known as vasopressin. ADH is produced in the hypothalamus and then transported to the posterior pituitary gland, where it is released into the bloodstream. Its primary function is to promote water reabsorption in the kidneys, reducing urine output and helping maintain blood volume and blood pressure.

In contrast, the other hormones listed are all associated with the anterior pituitary gland. Thyroid hormone is actually produced by the thyroid gland and is not secreted by the pituitary at all, while growth hormone and follicle-stimulating hormone are directly released by the anterior pituitary and are involved in different physiological processes such as growth regulation and reproductive functions, respectively. Therefore, understanding the origin and function of each hormone clarifies why anti-diuretic hormone stands out as the correct choice in this context.