Histochemical and autoradiographic studies of the formation of the metrial gland in the pregnant rat.

Abstract

AbstractIt is shown in this study that cells of the mesometrial triangle proliferate at a high rate in the early formative period of the metrial gland. This, plus observations of sequential apperance of specific cell types during growth of this tissue, indicate that the metrial cells are formed in situ.Support for the hypothesis of in situ formation of metrial gland tissue also was obtained by observation of apparent differentiation of metrial cells from a precursor cell type. The precursor cells appear to arise from fibroblast‐like cells located in the mesometrial triangle throughout the formative period of the metrial gland. Quantitative autoradiographic studies indicate that the precursor cells accumulate glycogen, undergo division, and subsequently produce diastase‐resistant, PAS‐positive granules that are characteristic of metrial cells. These cells, which contain specific granules and glycogen, are an individual cell type and are referred to as mononucleate metrial cells. The experiments suggest that the mononucleate metrial cells undergo karyokinesis without cytokinesis resulting in typical binucleate metrial cells. Binucleate metrial cells synthesize DNA and appear to become polyploid rather than forming multinucleated cells or binucleate daughter cells. Some nuclei apparently attain a high ploidy, but the majority of binucleates are not highly polyploid.