Detection of vitellogenin incorporation into zebrafish oocytes by FITC fluorescence

Large volumes of lymph can be collected from the eye-sacs of bubble-eye goldfish. We attempted to induce vitellogenin (Vtg) in the eye-sac lymph of bubble-eye goldfish and develop a method for visualizing Vtg incorporation by zebrafish oocytes using FITC-labeling. Estrogen efficiently induced Vtg in the eye-sac lymph of goldfish. After FITC-labeled Vtg was prepared, it was injected into mature female zebrafish. Incorporation of FITC-labeled Vtg by zebrafish oocytes was detected in in vivo and in vitro experiments. The embryos obtained from zebrafish females injected with FITC-labeled Vtg emitted FITC fluorescence from the yolk sac and developed normally. This method for achieving Vtg incorporation by zebrafish oocytes could be useful in experiments related to the development and endocrinology of zebrafish oocytes.