Substance P isolated from bovine hypothalamus: amino acid composition.

Using the method of Chang and Leeman for isolation the sialogogic undecapeptide from bovine hypothalamus partly purified Substance P was obtained. The final steps of purification were omitted to prevent losing of other peptides possessing biological activity of Substance P. The qualitative and quantitative content of amino acids in the hypothalamic extract was determined and fourteen amino acids were found. Four of them were not present in the sialogogic undecapeptide or neurotensin. It can be concluded that in the hypothalamic tissue apart from sialogogic undecapeptide and neurotensin, there are other peptides related to these two.