Many neurotransmitters may be involved in central regulation of body tempera ture in normothermia, during heat and cold stress, in fever, and in exercise. Emphasis on amines and prostaglandins has declined somewhat, and a major focus in recent years has been upon the possibility that certain peptides partici pate in central nervous system (CNS) mediation of temperature control (9, 10). Several of these peptides were originally isolated from pituitary tissue or the alimentary canal, but they also occur in widespread regions of the CNS. While some, such as adrenocorticotropic hormone (ACTH), have well known func tions in the periphery, the central roles of most peptides are much less un derstood.