[In vitro culture of oocytes from growing mice: behavior in defined medium and in the presence of follicular cells].

To approach the problem of the possible role of granulosa cells in oocyte growth we utilized different systems for the culture in defined medium, isolated oocyte culture in "conditioned medium" from follicle culture, isolated oocyte-follicle cells coculture. Tests for metabolic functions indicate that the oocytes maintain the same steady level of 3H leucine incorporation and fail to grow in all of the culture systems considered. In isolated follicle culture, however, granulosa cell enclosed oocytes increase in volume. The results support the hypothesis that junctional association between oocytes and granulosa cells must be maintained to promote oocytes growth "in vitro".