A radioimmunoassay for gamma-melanocyte stimulating hormone

A specific radioimmunoassay for γ-melanocyte stimulating hormone-like peptides has been developed. An antiserum raised in rabbit to synthetic bovine γ₃-MSH, one of the possible γ-MSH peptides, specifically recognizes the portion between His⁵ and Arg¹⁴ of γ₃-MSH without significant cross-reaction with other synthetic γ-MSH-like peptides, α-, β-MSH, adrenocorticotropin, and β-endorphin. The usable range of this RIA is 10 pg to 600 pg of synthetic γ₃-MSH. Three immunoreactive γ-MSH peaks were thus found in gel permeation chromatography of the whole bovine pituitary extract.