926 



SPERM, OVA, AND PREGNANCY 



test. Instead, extremely minute, lipid drop- 

 lets giving an Ashbel-Seligman reaction are 

 present in the epithelium of the uterine mu- 

 cosa (Figs. 15.15 and 15.22). Later in ges- 

 tation, from about the 20-cm. stage on, 

 large sudanophilic lipid droplets begin to 

 appear in the basal ends of the columnar 

 trophoblastic cells of the chorionic fossae 

 (Wislocki and Dempsey, 1946b), but these 

 have not been studied by other histochemi- 

 cal reactions for lipids. 



B. GLYCOGEN AND CARBOHYDRATE 

 CONTAINING MACROMOLECULES 



Since Claude Bernard suggested in 1859 

 that the placenta may perform the glyco- 

 genic function for the embryo before the de- 

 veloping liver has acquired this function, 

 considerable attention has been given to lo- 

 calizing this important metabolic reserve. 

 In previous paragraphs, the localization and 

 fluctuations in glycogen were reviewed for 

 the human placenta. In this species, glyco- 

 gen has a widespread distribution during 

 the first 2 months, occurring in the syncy- 

 tium, Langhans cells, stromal fibroblasts, 

 Hofbauer cells, peripheral cytotrophoblasts, 

 and decidual cells. After the second month, 

 there is a sharp decline in glycogen storage 

 in all these components, except in the de- 



cidual cells which retain glycogen until 

 term. This decline has also been recorded 

 biochemically by Villee (1953) whose meas- 

 urements of glycogen content show a rapid 

 drop after 8 weeks of gestation. Further- 

 more, glucose production is possible early in 

 gestation but not at term (Villee, 1953). 

 Concerning Bernard's hypothesis, it is inter- 

 esting to note Villee's observation that the 

 glycogenic storage function of the human 

 fetal liver is acciuired at 7 to 8 weeks of ges- 

 tation. Thereafter, the glycogen content of 

 the fetal liver rises sharply, as placental 

 glycogen content falls. 



Glycogen storage in the rat placenta is 

 also widespread, occurring in various parts 

 of the maternal-fetal complex (Goldman, 

 1912; Krehbiel, 1937; Bridgman, 1948a, b; 

 Padykula, 1958b; Bulmer and Dickson, 

 1960). Early storage during the first ten 

 days is chiefly a decidual function. How- 

 ever, the trophoblastic ectoplacental cone 

 and its later derivative, the spongy zone, 

 contain some glycogen from implantation 

 until term, with peak storage occurring the 

 15th day of gestation. The vascularized tro- 

 phoblast of the labyrinth and the visceral 

 endoderm of the inverted yolk sac placenta 

 initiate glycogen storage at 14 days, reach 

 a peak at 18 days, and have released most 



Pl.\te 15. XIII 



Fig. 15.54. A portion of a human chorionic villus at 21/2 months of gestation, stained by 

 the periodic acid-Schiff (PAS) method (exposed to saliva). Orth's fixative. Observe the 

 marked reaction of the outer zone of the syncytium, the delicate stippling of the deeper 

 layer, the chromophobic appearance of the Langhans cells, the intense staining of the base- 

 ment membrane and the strong response of the large vacuolated Hofbauer cell. Compare with 

 Figure 1529. X 7 ocular; X 90 objective. 



Fig. 15.55. Cytotrophoblasts from a human placental septum at full term, showing the 

 cells partially surrounded by dark red stained fibrin. Orth's fixative. PAS stain. The cytoplasm 

 of the trophoblasts contains a delicate stippling of PAS positive material as well as accen- 

 tuated staining around the nuclear membrane. Compare with Figure 15.48. X 7 ocular; X 90 

 objective. 



Fig. 15.56. A lamella of a cat's placenta, stained by the PAS method. Orth's fixative. Treat- 

 ment with saliva. Observe the intense reaction in a narrow zone located between the ma- 

 ternal capillaries and giant decidual cells and the trophoblastic sjmcytium. In the tropho- 

 blast occasional large intensely stained droplets of "colloid" are visible. Compare with Figures 

 15.60 and 15.61. X 7 ocular; X 60 objective. 



Fig. 15.57. A degenerating placental villus at 6 months of gestation, consisting of degen- 

 erating stroma which has become intensely metachromatic (red), surrounded by a mantle 

 of bluish green-stained, hyalinized syncytium. Basic lead acetate fixative. Toluidin blue 

 stain. Compare with Figure 15.51. X 7 ocular; X 20 objective. 



Fig. 15.58. The decidua basalis of a human placenta at 2V2 months of gestation, illustrating 

 the characteristic red metachromasia of the ground substance surrounding the decidual cells. 

 A cleft in the decidua contains bluish green-stained fibrin. Basic lead acetate fixative. Com- 

 pare with Figure 15.52, stained by PAS reagents. Toluidin blue stain. X 7 ocular; X 40 ob- 

 jective. 



