In vitro effect of methyl farnesoate on the vitellogenin content of ovary and hepatopancreas, in the crayfish Cherax quadricarinatus

Vitellogenin levels were determined in pieces of either ovary or hepatopancreas taken from females of the crayfish Cherax quadricarinatus during both early pre-reproductive and reproductive periods, and exposed in vitro to 0.15, 1.5, or 15 mu M of the juvenoid methyl farnesoate (MF). A significant accumulation of vitellogenin was seen in ovaries treated with 15 mu M of MF during the early pre-reproductive period. Besides, protein synthesis, measured as tritiated leucine incorporation, was correspondingly increased in ovaries taken during both pre- and post-reproductive periods and exposed to 15 mu M of M F. On the other hand, no stimulating effect of M F on the vitellogenin content of the hepatopancreas was seen in any period. These results, taken together, support the hypothesis of the endogenous vitellogenin synthesis stimulated by MF during the early ovarian maturation. However, this hormone was not able to stimulate vitellogenin synthesis in the ovary during the reproductive period.