UBC Theses and Dissertations
Ultrastructure of the rat ovarian germinal epithelium and its permeability to electron microscopically demonstrable tracer molecules Donaldson, Ranald Ross
The detailed fine structure of normal rat ovarian germinal epithelium was studied by means of transmission and scanning electron microscopy. The germinal epithelium possesses features suggestive of an absorptive and/or secretory capacity, a marked protein synthetic ability, and possible steroid metabolism. These and other cellular features were in turn indicative of a possible germinal epithelial involvement in transcellular movement of particulate substances. In order to investigate the permeability of the germinal epithelium to molecules from the peritoneal cavity, two electron microscopic tracer molecules, horseradish peroxidase (HRP) and ferritin, were injected intraperitoneally. The results indicate that there is a differential movement of these two molecules across the germinal epithelium, presumably related to the difference; in their molecular dimensions. The predominant route of movement of HRP is extracellular, apparently by diffusion through the intercellular clefts. Ferritin movement, on the other hand, is intracellular, via a vesicular transport mechanism associated with pinocytotic activity at the apical surface of the germinal epithelial cells. It is concluded that the germinal epithelium is a metabolically active tissue which plays both a passive and an active role in the movement of molecules from the peritoneal cavity.
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