ABSTRACT
In the case of hormones originally identified in the pituitary, adrenocorticotropin was the first described in the immune system. The studies to date clearly show that cells of the immune system contain receptors for neuropeptides and can also be considered a source of pituitary, hypothalamic, and neural peptides. In addition to hormones commonly found in the neuroendocrine system, a number of other peptides have also been identified as being produced by cells of the immune system. When one considers the increasing number of neuropeptides so far identified, it seems that virtually all known neuropeptides will be found in the immune system and many produced by cells of the immune system. In the case for prolactin receptors, they have been found on normal human and mouse lymphocytes including all the major immune cell types.
