Pituitary hormones in the brain: what is their function?

Data concerning the presence in the central nervous system of the anterior and intermediate lobe hormones ACTH, beta-lipotropin, alpha-melanocyte stimulating hormone, beta-endorphin, prolactin, growth hormone, gonadotrophic hormone, and thyrotropin stimulating hormone are reviewed. Available evidence for the ACTH-lipotropin family of peptides indicates that synthesis can occur in brain as well as in pituitary. Although behavioral effects have been described for some of these peptides and their fragments (ACTH, alpha-MSH, beta-endorphin, prolactin), the physiological relevance and the mechanisms of such effects, the nature of the biosynthetic pathways involved, and the factors regulating the brain concentrations of these peptides remain to be explored.