Parallel bioassay of physalaemin and hylambatin on smooth muscle preparations and blood pressure.

Hylambatin, a novel tachykinin endecapeptide isolated from the skin of the African frog Hylambates maculatus, must be ascribed to the physalaemin subfamily. It differs structurally from all other known tachykinins mainly in having a methionine residue replacing the usual leucine residue at position 2 from the C-terminus. In parallel bioassay on a number of in-vitro and in-vivo test objects, hylambatin and physalaemin were nearly indistinguishable from each other, with few moderate quantitative differences.