Hormonal control of vitellogenin synthesis in Pyrrhocoris apterus (L.) (Heteroptera)

Abstract

A vitellogenic female-specific protein was demonstrated in the haemolymph of Pyrrhocoris apterus females by electrophoresis under native conditions. One day before oviposition, eggs contained a major protein with electrophoretic mobility corresponding to that of haemolymph vitellogenin. SDS-PAGE revealed two subunits of the female-specific protein with M, 186 and 150 kDa. The latter was found together with several other polypeptides in the yolk. The identification of the 150 kDa polypeptide as vitellogenin was accomplished by means of ovariectomy and immunoblotting. In control bugs, temporal changes in the vitellogenin titre were recorded; traces of vitellogenin were found in the haemolymph and fat body on day 2 after adult ecdysis, its titre reached a maximum on day 4 and then decreased. Allatectomy of the females resulted in vitellogenin disappearance and a rise in 78 and 82 kDa polypeptides in the haemolymph. Application of a juvenile hormone analogue restored the ability of allatectomized females to produce female-specific polypeptides and to sequester them into the ovaries. The results showed that the synthesis of the 186 and 150 kDa polypeptides depended on juvenile hormone action.