Rh and Releasing factor

Rh noun - A blood group antigen possessed by Rh-positive people; if an Rh-negative person receives a blood transfusion from an Rh-positive person it can result in hemolysis and anemia.

Releasing factor and rh are semantically related. In some cases you can use "Releasing factor" instead a noun "Rh".

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.

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