Abstract
The morphological changes of granulated metrial gland (GMG) cells were investigated in 10-day, 14-day, 19-day pregnant, and post partum rats, using light and electron microscopy. The effect of Prostaglandin F2α (PGF2α) on the pregnant uterus was also examined. The GMG cells began to appear at day 10 and reached their maximum number at day 14. On the 19th day of pregnancy myelination and vacuolation of the granules were noted in these cells, which subsequently seemed to degenerate. After parturition, most of the degenerated GMG cells were shown to be phagocytized by macrophages. PGF2α given at day 14, caused similar, but more abrupt, changes of the GMG cells. In addition, it was demonstrated that some of the remaining GMG cells were replaced by myoblasts which contained myofilaments in the cytoplasm.
An autoradiography (ARG) technique was employed to detect the PGF2αreceptors. Developed silver grains were found in the GMG cells and in smooth muscle cells, but there were no receptors found in the interstitial tissue.
Immunohistochemical staining with rabbit anti-rat relaxin serum showed a very strong reaction in luteal cells, as has been reported in the literature. The GMG cells had a similar reaction, although weak compared to the luteal cells.
These results may indicate that the GMG cells originate from the smooth muscle cells and are associated with contraction and relaxation of the pregnant uterus.
