Primary structure of four allatostatins: neuropeptide inhibitors of juvenile hormone synthesis.

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Abstract
Four neuropeptides that inhibit juvenile hormone synthesis by the corpora allata have been isolated from brains of the virgin female cockroach Diploptera punctata. These allatostatins are 8-13 amino acids long, are amidated, and show sequence similarity, including a 3-amino acid sequence at the C-terminal end that is common to all four peptides. The peptide sequences are as follows: allatostatin 1, Ala-Pro-Ser-Gly-Ala-Gln-Arg-Leu-Tyr-Gly-Phe-Gly-Leu-NH2; allatostatin 2, Gly-Asp-Gly-Arg-Leu-Tyr-Ala-Phe-Gly-Leu-NH2; and allatostatin 3, Gly-Gly-Ser-Leu-Tyr-Ser-Phe-Gly-Leu-NH2; and allatostain 4, Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-NH2. An in vitro bioassay of the synthesized allatostatins showed > 40% inhibition of juvenile hormone synthesis by corpora allata of virgin females with 10-9 M allatostatin 1, 10-8 M allatostatins 2 and 4, and 7 .times. 10-7 M allatostatin 3. Inhibition by allatostatins 1-4 was reversible. In addition, allatostatin 1 inhibited juvenile hormone synthesis by corpora allata from mated females and last-instar larvae of D. punctata and corpora allata of adult female Periplaneta americana.