Localization of glycogen in the human placenta

Abstract

Glycogen was determined by the Bauer-Feulgen method in the chorion and placenta of 4- to 40-weeks-pregnant women. It could be detected through the whole pregnancy in the ectodermal epithelium of the amnion and mesenchymal cells of the chorion laeve, extraplacental chorion, and amnion. Glycogen was also found throughout the entire cross section of the umbilical cord up to the 16th week inclusive; at the 20th week of pregnancy glycogen was determined only in the wall of the umbilical vessels with an insignificant spread beyond the muscular layer of the umbilical vein. With the progress of pregnancy the amount of glycogen in the cellular nodules increased, but in the last third of pregnancy, with the rise of the fibrinoid content, the amount of glycogen in the cellular nodules began to drop; at the 40th week of pregnancy it could be detected only in small amounts between the cells. The glycogen level in the stroma of the villi was low at first, but rose later; large amounts of glycogen were found in the stroma of the larger and stem villi during the last half of pregnancy; it was almost entirely absent in the stroma of smaller villi. Glycogen was revealed in the Langhans' cells throughout the whole period of pregnancy, whereas in the syncitial layer of the trophoblast it was absent altogether.