Sensitive enzyme immunoassay for Manduca allatotropin and the existence of an allatotropin-immunoreactive peptide in Periplaneta americana

Antisera to Manduca sexta allatoropin were raised in rabbits and were used to develop a competitive enzyme immunoassay for this neuropeptide. The detection limit of the assay is less than 2 fmol/well. A useful quantification can be obtained from 2 to 30 fmol/well. No cross-reactivity was observed with several insect peptides, but the enzyme-linked immunosorbent assay does recognize Ala⁶, Leu⁷, Ser⁸]-allatotropin, a myotropin recently isolated from Locusta migratoria. The assay was used to study the distribution of allatotropin within the nervous system of Manduca sexta. The peptide is present in the retrocerebral complex, the brain, and the ventral nerve cord of this species, in quantities of respectively 0.01, 1.2, and 1.7 pmol per insect. An allatotropin-immunoreactive peptide was found in the nervous system of Periplaneta americana. It is present in the ventral nerve cord (3.3 pmol/insect), brain (1.9 pmol/insect), and retrocerebral complex (0.09 pmol/insect). These data suggest that peptides of this family are generally present in insects. © 1993 Wiley-Liss, Inc.