Pituitary cells were shown to release corticotropin (ACTH) in response to interleukin-2 (IL-2) and to express a protein that is related to the α-chain of the IL-2 receptor (IL-2R). The α-chain-like molecule was bound by a rat monoclonal antibody to the murine IL-2 receptor as well as to IL-2. Sodium dodecylsulfate-polyacrylamide gel electrophoretic analysis of the affinity-purified material from pituitary cells demonstrated a protein which was similar to that which was isolated from activated splenocytes. Thus, IL-2 and its receptor may be one of several hormone-receptor pairs utilized by both the immune and neuroendocrine systems for intersystem communication. © 1989.