The rabbit stomach metabolic precursor of PHLIP-8, a physalaemin-like octapeptide with the amino acid sequence less than Glu-Val-Asp-Pro-Asn-Ile-Gln-Ala, is apparently a glycoprotein, however, precise structural characterization has not been performed. In order to determine the nature of the precursor(s) in nerve and lung tissue, attempts have been made to raise antisera to thyroglobulin-PHLIP-8 complexes; characterization of the antisera has yet to be completed. Bioassays have indicated that, while PHLIP-8 does not possess typical tachykinin properties, relatively large concentrations of this peptide will facilitate enhanced contractile responsiveness in several smooth muscle preparations and, in the rabbit, it lowers blood pressure.
