alpha-MSH and neurofilament M-protein share a continuous epitope but not extended sequences. An explanation for neurofibrillary staining with alpha-MSH antibodies.

The long recognized neurofibrillary immunoreactivity of the nervous system with alpha-MSH antibodies arises from an epitope on neurofilament M-protein which we have now characterized. It is situated in the amino terminal residues where M-protein and alpha-MSH exhibit similar but not identical sequences. Their divergence past residue 5 precludes a physiological significance of the crossreactivity which seems to have arisen fortuitously. Our results question previous speculations as to the existence of extrapituitary alpha-MSH-like hormones.