INVITRO DEVELOPMENT OF EARLY POSTIMPLANTATION RAT EMBRYOS

Rat embryos explanted at 7 1 2 or 8 1 2post coitum were cultured throughout the major stages of organogenesis in a system of rotating bottles containing heat-inactivated, immediately centrifuged (I.C.) serum. About 80% of the 8 1 2-day explants and 50% of the 7 1 2-day explants developed a blood circulation in the yolk sac; in these embryos, organogenesis and growth rates were similar to those of embryos in vivo. In cultures continued for 4 or 5 days, many of the embryos developed 30-40 somites. There was little difference in the subsequent development of embryos cultured in maternal serum or male serum during the egg-cylinder stage except for a possible decrease in the frequency of normal axial rotation in embryos from the male serum. Development in rotator bottles was much better than in watchglass cultures. © 1978.