Effect of a peptide and some of its analogs on the reproduction of Sarcophaga bullata and Locusta migratoria

The studies on freshly emerged female flies Sarcophaga bullata (Diptera) or Locusta migratoria (Orthoptera), respectively, demonstrate that oogenis is strongly affected by an injection of the oostatic peptide and also by its synthesized analogs with a lowered number of proline residues: H - Tyr - As p - Pro - Ala - X - Oft where X = Pro(n), n = 0 to 5. The effects of these peptides were followed by hatchability as well as morphological and histolo gical analyses of the developing eggs. Radiolabelling of the biologically active peptides made possible to study t he time coarses of the distribution of them and their metabolites in the tr eated mother body and moreover, their transfer into organs of males and fem ales of the next generation The kinetics evaluated in this way in the treat ed insect body was correlated with the corresponding morphological and hist ological analyses. To study the possible relationship between the peptide structure and regula tion of insect reproduction, corresponding peptide isosters and cyclopeptid es were also synthesized and tested.