AN ELECTRON MICROSCOPIC STUDY OF THE EFFECTS OF HYPERVITAMINOSIS A ON THE MATERNAL-EMBRYONIC RELATIONSHIP OF THE RAT AT 8 DAYS OF PREGNANCY

Abstract

Summary. The decidual and trophoblastic tissue of the rat 5 hr after the maternal administration of 100,000 i.u. vitamin A palmitate has been studied using light and electron microscopy. The experimental tissue showed an increase in the surface area of membranes comparable to that previously described in cultures in the presence of excess vitamin A. Lipid droplets which may consist of vitamin A were seen in the blood, and most of the membrane damage was close to the capillaries. Vacuolated and distorted blood cells were observed, and cell débris was present in the blood space around the embryo. Decreased oxygen-carrying capacity and increased peripheral resistance were suggested as maternal vascular factors which may complement the direct embryotoxic effect of vitamin A in the teratogenic mechanism.