SPERM, OVA, AND PREGNANCY 



of the follicle need to be clarified and offer 

 excellent opportunities for more detailed 

 investigation. 



Studies of the various microscopically 

 visible components of the ooplasm of mam- 

 malian eggs have not advanced as rap- 

 idly and significantly as have studies deal- 

 ing with similar elements in the eggs of 

 the lower vertebrates and invertebrates 

 (Claude, 1941; Holtfreter, 1946a, b; Schra- 

 der and Leuchtenberger, 1952; Rebhun, 

 1956; Yamada, Muta, Motomura and Koga, 

 1957; Nath, 1960). 



Relatively little information is availal)lo 

 on the historv, biocliemical significance, and 



function of the cytoplasmic inclusions dur- 

 ing the period of growth, maturation, or 

 fertilization of the mammalian oocyte. In 

 the dog, cat, and rabbit Golgi material of 

 the young oocyte is first localized in the 

 region of the nucleus, but it is later dis- 

 tributed throughout the ooplasm and finally 

 aggregates near the cell periphery. The sub- 

 microscopic details of these shifts in the 

 organelles of the oocyte have now been 

 described for the rat and mouse. In oocytes 

 with a single layer of granulosa cells the 

 large Golgi complex lies at one pole of the 

 nucleus (Fig. 14.5). This position of the 

 Golgi complex is characteristic of primary 



I 1 



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NUCLEUS 



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MULTIVESICULAR 



BODIES 



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Fk;. 14.,5. Electron micrograpli of a portion of a imilammar or prniiary follirle obtained 

 fronn a rat 2 days postpartum. The large mitochondria have much matrix and few cristae. 

 The large Golgi complex is located at one pole of the nucleus. Note close apposition of granu- 

 losa cell membranes to oolemma! membrane. (Courtesy of Dr. L. Odor.) 



