releasing factor n 1: a substance produced by the hypothalamus that is capable of accelerating the secretion of a given hormone by the anterior pituitary gland [syn: {releasing factor}, {releasing hormone}, {RF}] 2: any of several hormones produced in the hypothalamus and carried by a vein to the anterior pituitary gland where they stimulate the release of anterior pituitary hormones; each of these hormones causes the anterior pituitary to secrete a specific hormone [syn: {releasing hormone}, {RH}, {releasing factor}, {hypothalamic releasing hormone}, {hypothalamic releasing factor}]