PATTERNS OF HEMOLYMPH VITELLOGENIN AND OVARIAN VITELLIN IN THE GERMAN-COCKROACH, AND THE ROLE OF JUVENILE-HORMONE

The concentrations of fat body and haemolymph vitellogenin and ovarian vitellin during the first gonadotropic cycle of the cockroach Blattel la germanica (L.) (Dictyoptera, Blattellidae) have been studied. For t hese purposes, a polyclonal antibody against B. germanica vitellogenin and vitellin has been obtained, and an ELISA to quantify these protei ns has been developed. Ovarian vitellin levels follow a pattern which parallels those of basal oocyte growth and Juvenile Hormone production by the corpora allata. This suggests that Juvenile Hormone regulates vitellogenin uptake into oocytes. Fat body and haemolymph vitellogenin levels give cyclic and parallel patterns. However, the cycle of Juven ile Hormone appears delayed with respect to that of vitellogenin. We s uggest that the production of Juvenile Hormone, although cyclic in pro file, does not modulate alone the cycle of vitellogenin. At least a su pplementary mechanism, apparently independent of Juvenile Hormone, may be involved in the decline of vitellogenin production at the end of t he vitellogenic cycle.