MIF-1, Tyr-MIF-1, and MSH: Control of MSH Release and Extra-pigmentary Effects

New brain peptides are being discovered with increasing frequency. The discovery of multiple forms of MSH and evidence for a novel peptide structurally related to MIF-1 may provide avenues for new insights into the mechanisms controlling MSH release Demonstration that levels of the new tetrapeptide Tyr-MIF-1 are higher in some parts of the brain than in others and can be altered by neuroendocrine manipulations raises the possibility that this peptide may affect CNS functions regardless of any effects on MSH release. Early studies on the extra-pigmentary effects of MSH and MIF-1, which ushered in the field of brain peptides, provide models for the exploration of these possibilities. Explanations for unusual dose-response relationships, chronic effects after neonatal injections, and the mechanisms by which peripherally administered peptides reach the brain to exert behavioral and EEG actions remain to be found