FINE-STRUCTURE OF RAT METRIAL GLAND IN RELATION TO ORIGIN OF GRANULATED CELLS

Abstract

The fine structure of the material gland of the rat was examined at days 12, 14, 16, 18 and 20 of pregnancy, at all these stages, 2 well differentiated cell types were seen. A relatively pale-staining cell containing numerous dense granules, the typical granulated metrial gland cell, was readily distinguished from a darkly stained fibroblast-like cell. Numerous cells could be identified which did not fit either of these categories. On the basis of morphological appearances these cells were placed in a series, with the members of the series showing a transition from a small cell with a high nuclear/cytoplasmic size ratio to a readily-identifiable metrial gland cell containing a few typical granules. The small cell, apparently the precursor of the granulated metrial gland cell, was characterized by a markedly hetochromatic nucleus; cytoplasmic organelles were sparse although there were occasional mitochondria and Golgi bodies. On morphological grounds this cell appeared to be from the lymphocyte series and was probably a small lymphocyte. The granulated cells may have an immunological role.