Abstract: This invention provides a new class of hormone-like peptides having the following sequence:a-X.sub.1 -Arg-Val-X.sub.2 -[(Gln).sub.m)-(Val).sub.n -(Gly).sub.o - (X.sub.3).sub.p -(X.sub.4).sub.q -(Pro).sub.r -(X.sub.5).sub.s -(X.sub.6).sub.t -(X.sub.7).sub.u ]-cwherein the definitions for the various substituents and amino acids are given in the specification. The peptide is synthesized by a method which comprises protecting the amino group of the amino acids; forming a metal salt of the protected amino acid at the beginning of the sequence; coupling the salt to a resin; coupling the amino acids in sequence to the resin to form the peptide; cleaving the formed peptide from the resin; removal of the remaining protecting groups; and final purification of the synthesized peptide by either extraction and gel-filtration or Biogel P2-500. The peptides, some of which have also been extracted from the brains of estivating lungfish Protopterus annectens (Owen), have biological activity.

Abstract: Novel hormone-like peptides having an anti-metabolic biological activity have been isolated from the brains of estivating lungfish Protopterus annectens (Owen) and have the following formula:a-X.sub.1 -arg-val-X.sub.2 -gln-val-gly-X.sub.3 -X.sub.4 -pro-X.sub.5 -(gly).sub.n -(asp).sub.m -c,wherein, a, X.sub.1, X.sub.2, X.sub.3, X.sub.4, X.sub.5, c, n and m are defined in the specification.Both hypothermic and decreased oxygen consumption activity have been demonstrated in in vivo tests. In vitro tests have demonstrated suppression of DNA-production followed by a decrease in protein biosynthesis.