INHIBITION OF VITELLOGENIN PRODUCTION BY ALLATOSTATIN IN THE GERMAN-COCKROACH

Allatostatins with a typical YXFGL-amide C-terminus constitute a neuro peptide family, which was discovered because of its inhibitory action on insect juvenile hormone synthesis. In the search for possible new f unctions for allatostatins we focused our attention on the fat body. O ur previous studies on the cockroach Blattella germanica suggested the occurrence of factors terminating vitellogenesis, and the hypothesis here was that allatostatins might be one of these factors. Our experim ents have shown that allatostatin impaired vitellogenin release in fat bodies incubated in vitro, and that this effect appears to be mediate d by the inhibition of vitellogenin glycosylation. Fluvastatin also in hibited vitellogenin release, and mevalonolactone counteracted the inh ibitory effects of allatostatin. These results suggest that allatostat in acts upon the mevalonate pathway and synthesis of dolichol, which w ould explain the inhibition of vitellogenin glycosylation. We finally conclude that allatostatins may effectively contribute to the terminat ion of the vitellogenic cycle in B. germanica.