Histochemical investigation of the folliculogenesis in the ovary of the Mongolian gerbil (Meriones unguiculatus).

The ovaries of 70 mature Mongolian gerbils (Meriones unguiculatus) were investigated morphologically and enzyme histochemistry for the appearance of acid phosphatase, non-specific esterases, succinate dehydrogenase and thiamine pyrophosphatase. In the oocyte two particular enzyme active zones exist depending on the state of development. In young oocytes acid phosphatase, succinate dehydrogenase and thiamine pyrophosphatase can be found only in the perinuclear zone. From the late secondary follicle on, activity of acid phosphatase, succinate dehydrogenase and non-specific esterases can be detected only in a peripheral area of cytoplasm, whereas thiamine pyrophosphatase is present in the entire ooplasm. In the follicular epithelium a different pattern of enzyme distribution suggests a functional differentiation of the epithelial cells during folliculogenesis.