Intercellular communication between granulosa cells and mouse oocytes: Existence and possible nutritional role during oocyte growth

Abstract

Intercellular communication between granulosa cells and mouse oocytes has been examined during oocyte growth in vivo and in vitro. Intercellular communication, as assessed by transfer of fluorescein dye from oocytes to surrounding granulosa cells and metabolic cooperativity between the two cell types, existed throughout the period of oocyte growth examined (mean oocyte diameter increased from about 45 to about 65 μm). The extent of metabolic cooperativity for radiolabeled 2-deoxyglucose increased during oocyte growth in vivo and in vitro as a linear function of oocyte surface area. The extent of 2-deoxyglucose metabolic cooperativity between granulosa cells and oocytes of similar size was a linear function of the number of attached granulosa cells. Thus, the increase in the extent of metabolic cooperativity for 2-deoxyglucose during oocyte growth was probably due to formation of additional heterologous gap junctions between oocytes and new granulosa cells which come into contact with the growing oocyte. The rate of oocyte growth in vitro was positively correlated with the extent of 2-deoxyglucose metabolic cooperativity. A nutritional role for intercellular communication between granulosa cells and the oocyte in oocyte growth is discussed.