Paper - Reproduction (1949)

From Embryology

Catchpole HR. Reproduction. (1949) Annu Rev Physiol. 11: 21-44.


By Husbert R. Catchpole

Department of Pathology, University of Illinois College of Medicine Chicago, Illinois

  • This review covers the period from April 1, 1947 to June 1, 1948. 21

The Ovary and Ovulation

Human ova. — An eighty-year quest for early human embryos, dating from the discovery of the Reichart ovum of 1868, reached a climax in the work of Rock, Hertig & Menkin (132, 171). The youngest embryos, two of two cells éach and two of three cells, were obtained by exposure of ova from unruptured follicles to human sperm in watch glasses. The naturally fertilized ovum is believed to reach the uterus on the third day, and on the sixth day it is a blastocyst of three tissues and begins the erosion of the maternal endometrium. On the ninth day, the trophoblast has been seen entering a maternal sinusoid. Development has been followed in this series till the fourteenth day, when the primitive streak appears. Robertson e¢ a}. (170) well illustrated and described a normal human embryo of seventeen days.

Histochemistry of the ovary.—In a critical examination of histochemical reactions of the ketosteroids, Claesson & Hillarp (34) concluded, in agreement with Gomori (75), that the substance reacting with phenylhydrazine was, in all probability, plasmal, and that at the present time it is not possible to demonstrate histochemically any carbonyl group of a ketosteroid. These authors have shown a substance in the ovary, having the polarization characteristics of cholesterol, which they believe to be the precursor of estrogenic hormone. In preovulatory follicles, the precursor is stored in the theca interna in the rat and rabbit, and in the interstitial gland of rat, rabbit, and guinea pig; it is lowest in amount in estrus and diestrus (32, 33). Analyses of total cholesterol in the ovaries of cyclic, pregnant, and lactating rats led Perlman & Leonard (149) to conclude that a close relationship existed between cholesterol and progesterone. In a study of glycogen and carbohydrate-protein complexes in the ovary of the rat during the estrus cycle, Harter (94) found the normally developing ovum to be the only cell with appreciable amounts of glycogen, while ovum, zona pellucida, granulosa cells of the follicle, luteal cells, macrophages, follicular fluid, intercellular substance, and basement membranes contained stainable glycoprotein. Increased cytoplasmic glycoprotein of the granulosa cells was related to antrum formation and follicular growth. The glycoproteins of normal and atretic ova differed in their solubility properties. The zona pellucida reacted to extractives in such a way as to suggest that its penetration by sperm cells could be due to a local increase in hydrogen ion concentration. An elegant method was used by Claesson (35) to show rather conclusively the absence of smooth muscle in the wall of the graffian follicle of cow, swine, rabbit, and guinea pig, when the application of classical staining methods failed to distinguish between smooth muscle and connective tissue. This demonstration depends on a decisive difference between the intrinsic molecular birefringence of muscle and the form birefringence of connective tissue. In studies of rabbit ovaries from sex differentiation to maturity, Duke (50) concluded that the connective tissue of the ovary is in a dynamic state and that the maturation of a follicle involves the thinning out and disappearance of the overlying tunica albuginea.