Internal secretion and Releasing factor

Internal secretion noun - The secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect.

Releasing factor and internal secretion are semantically related. In some cases you can replace phrase "Releasing factor" with "Internal secretion", this phrases are similar.

Releasing factor noun - 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.

Internal secretion and releasing factor are semantically related. You can use "Internal secretion" instead a noun phrase "Releasing factor".