ASSOCIATION BETWEEN CALBINDIN-D-28K AND OOGENESIS IN OVARIES OF CHICKEN EMBRYOS IN-VITRO

The left ovary of chicken embryos was removed and incubated in culture medium with a thymidine analogue, bromodeoxyuridine (BrdU), in vitro. In addition, fertile chicken eggs were injected with BrdU via the ext raembryonic vessels and incubated for 24 hours. The ovaries were then processed for immunohistochemical localization of calbindin-D-28K (a 2 8kd vitamin D-dependent calcium-binding protein) and BrdU. Calbindin-D -28K was detected in the germinal epithelium and in cells surrounding the oogonia and oocytes (future granulosa cells) of the embryonic chic ken ovary. However, BrdU was observed in the nucleus of the oogonia an d oocytes of the chicken embryonic ovaries. Comparison of the 2 adjace nt sections, immunostained for calbindin-D-28K and BrdU consecutively, indicated that BrdU, the marker for cell proliferation was not detect ed in calbindin-D-28K-containing cells, namely, germinal epithelium an d future granulosa cells, in the ovary of chicken embryos. These resul ts suggested that calbindin-D-28K-containing cells in the ovary were n ot in the process of cell division during the 24-hour incubation of ch icken embryos.