The hypothalamus controls the anterior pituitary by means of: a. releasing hormones b. second messengers c. third messengers d. antibodies e. cytokines.

a. releasing hormones

Explanation:

Releasing hormones are the hormones synthesized by hypothalamic neurons and serve to stimulate the anterior pituitary gland to secrete its hormones into the blood through secondary capillary plexus. Each of the releasing hormones stimulates the release of specific hormone from the anterior pituitary.

For example, the growth hormone-releasing hormone (GHRH) stimulates the release of growth hormone while thyrotropin-releasing hormone (TRH) stimulates the release of thyroid-stimulating hormone (TSH) from the anterior pituitary.

Hence, the hypothalamus regulates the release of hormones from the anterior pituitary gland through its releasing hormones.