The differentiation of granulated metrial gland cells in chimeric mice and the effect of uterine shielding during irradiation.

The differentiation of granulated metrial gland (GMG) cells has been investigated during deciduomata formation in radiation-induced chimeric mice reconstituted with rat or mouse bone marrow. The extent of the decidual reaction was apparently normal in regions of the uterine horns shielded from the irradiation but was impaired in, or absent from, the irradiated horns. The numbers of GMG cells which differentiated varied but were greater in the larger decidual swellings. The distinct morphological differences between rat and mouse GMG cells were used to analyse the GMG cells which differentiated in mice reconstituted with rat bone marrow. Only rat GMG cells were identified in the unshielded horns showing that bone marrow cells provide precursors for GMG cells. However, both rat and mouse GMG cells were found in the horns shielded from the irradiation. This indicates that some precursors for mouse GMG cells are present in the uterus at the time of the irradiation and are protected by the lead shield to survive and differentiate in situ. Furthermore they do not circulate to replace the precursors killed in the unshielded horn.