Anin vitro study of programmed death in rat placental giant cells

✍ Scribed by Dorgan, W. J. ;Schultz, R. L.

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: English
• Weight: 1024 KB
• Volume: 178
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401780407

✦ Synopsis

Placental giant cells were removed from rats at day 13 of' pregnancy and maintained in vitro. The giant cells demonstrated a fixed age limit or programmed cell death in culture that corresponded to their life span in vivo. They began to decrease in number by the equivalent of day 17 of pregnancy and completely disappeared from the cultures by the equivalent of day 23 of pregnancy.

Radioactive tracers were used to determine the synthesis of DNA, RNA and protein throughout the life span in vitro of giant cells. The cells were not observed to divide on or after the equivalent of day 13 of pregnancy but DNA synthesis was continuous up to the equivalent of day 16 of pregnancy. The DNA synthesis on or after the equivalent of day 13 was thought to be a result of endoreplication of DNA. RNA synthesis was observed to occur throughout the life span in vitro of the giant cell with a possible reduction after the equivalent of day 19 of pregnancy. In cell cultures RNA synthesis was observed first in the non-nucleolar portion of the nucleus and then in the nucleoli. The labeled RNA (both nucleolar and non-nucleolar) then appeared to migrate to the cytoplasm. Time lapse cinematography studies also demonstrated the apparent movement of nucleolar material from the nucleus to the cytoplasm.

Protein synthesis was observed to occur throughout the life span in vitro of the giant cells.