Fast induction of vitellogenin gene expression by juvenile hormone III in the cockroach Blattella germanica (L.) (Dictyoptera, Blattellidae)

The present paper describes the effect of juvenile hormone III (JH III) upo n vitellogenin (Vg) gene expression in cardioallatectomized females of Blat tella germanica. Northern blot analyses of time course studies showed that Vg mRNA can be detected 2 h after the treatment with 1 mu g of JH III. West ern blot analyses revealed that Vg protein is detectable 4 h after the same treatment. The study of the influence of the age showed that 48-h-old fema les seem more sensitive than 24-h-old females, whereas differences were les s apparent between 48- and 72-h-old females. Dose-response studies indicate d that 0.01 mu g of JH III is ineffective, whereas the doses of 0.1, 1 and 10 mu g induced the synthesis of Vg in a dose-dependent fashion. Finally, t he administration of three successive doses, of 0.01 mu g of JH III each, d id not result in detectable Vg production, whereas two doses of 0.01 mu g f ollowed by one of 1 mu g of JH III induced a greater response than that res ulting from a sole dose of 1 mu g of JH III, which suggests that sub-effect ive doses of JH III elicit a priming effect on Vg production. (C) 1999 Publ ished by Elsevier Science Ltd. All rights reserved.