Steroidogenic function of the intra-arterial trophoblast in the rat. Ultrastructural, histoenzymologic and biochemical data
Legrand, C.
Journal de Gynecologie Obstetrique et Biologie de la Reproduction 4(8): 1017-1035
1975
ISSN/ISBN: 0368-2315 PMID: 1240105 Document Number: 85954
The large cells of fetal origin lying in the afferent arterial sinus, myometrial arterioles and segmentary arteries of hemochorial placentas have been demonstrated to have a trophoblastic function, and are investigated here in rats by electron microscope, histochemistry, and biochemistry. At 11 days of gestation these cells begin to migrate into the maternal sinus, and have an undifferentiated appearance with many polysomes. By Day 13 the endoplasmic reticulum occupies most of the cell, with cisternae and Golgi vesicles typical of glycoprotein secretion. A glycoprotein cell coat covered the cell surface. Few lysosomes containing acid phosphatase were present, having no phagocytic activity. Lipid pools with active mitochondria nearby were common. Intraarterial trophoblast tissues were dissected out and incubated for qualitative enzyme tests. Moderate delta-5,3-beta-hydroxysteroid dehydr ogenase and 17beta-hydroxysteroid dehydrogenase, and some 5alpha-3alpha- and 3beta-hydroxysteroid-dehydrogenase were present. No reduced 5beta-c ompounds were detected. The data suggested that both steroids and mucop roteins are formed by these cells, perhaps having immunosuppressive or local vasodilator roles.