Low doses of the pesticide lindane induce protein release by the fat body of female cockroach Blaberus craniifer (Dictyoptera)

Abstract

In the ovoviviparous cockroach Blaberus craniifer, low doses of the pesticide lindane (1–6 μg/g of body mass) have been implicated in the enhancement of ovarian growth and vitellogenesis onset in headless female ovaries. In order to investigate lindane effects on protein release by the fat body, we used antibodies raised against egg proteins to quantify protein levels in fat body, hemolymph and ovaries of treated–fed or –decapitated females 3- or 5-days -old. In vitro assays used fat body in Grace's medium to quantify the protein amount released in the medium. Individual data for each treatment were related to their corresponding control in paired series. In vivo, ovarian enhanced protein content was linked to an enhanced protein secretion by the fat body. This was ascertained in vitro by high levels of released protein in the medium containing lindane (1 μM) by fat body from females, but not from males. This effect was inhibited by EDTA, a calcium chelator. The present results confirmed that low doses of lindane (about 3 μg/g of body mass) acted as a juvenile hormone analogue, at the level of the ovaries, by enhancing protein uptake, and also at the level of the fat body, by triggering protein release. This property is calcium-dependent.