Vitellogenin synthesis by fat body and ovary in the terrestrial isopod, Armadillidium vulgare.

Vitellogenin synthesis in Armadillidium vulgare was investigated in tissue cultures. The synthesis of vitellogenin was assayed by the incorporation of [35S]methionine into precipitin with anti-vitellin serum. The forms of synthesized vitellogenin were analyzed by polyacrylamide gel electrophoresis and fluorography. The fat body synthesized vitellogenin and its rate was correlated with the molting cycle: a maximum level at stage D and lower levels at A-C and E of the molting cycle. Four forms of vitellogenin (Vg 1-4) were synthesized; the larger forms (Vg 1-2) were prominent. The ovary also synthesized a slight amount of vitellogenin at the end of the molting cycle. The smaller forms (Vg 3-4) were synthesized under cultured condition. Through vitellogenesis in A. vulgare, the fat body must be the principal site of vitellogenin synthesis. Most vitellogenin may be transported from the fat body to the ovary through hemolymph at stage D of the molting cycle.