Effect of methoprene and 20-hydroxyecdysone on vitellogenin production in cultured fat bodies and backless explants from unfed female Dermacentor variabilis

The effect of 20-hydroxyecdysone (20HE) and the juvenile hormone analogue m ethoprene (JHA) on vitellogenin (Vg) production in fat body organ cultures and backless explants of unfed female Demacentor variabilis was measured. A n indirect double antibody enzyme linked immunosorbent assay (ELISA) was de veloped using a monoclonal antibody that recognized a 98 kDa subunit of Vg and a Vg specific polyclonal antibody made against vitellin (Vn). Peak Vg t iters in culture medium from fat body cultures treated with 0.1 mu M 20HE o r 1 mu M 20HE were 24 ng/ml and 20 ng/ml respectively. In culture medium fr om backless explants treated with 0.1 mu M 20HE or 1 mu M 20HE, peak Vg tit ers were 36 ng/ml and 26 ng/ml, respectively. JHA produced only a slight in crease in Vg titers that was statistically different from Vg titers produce d by 20HE but was not statistically different from hormone-free controls. T hese results support the conclusion that Vg production in fat body trophocy tes of D. variabilis is regulated by 20HE. (C) 1999 Elsevier Science Ltd. A ll rights reserved.