Hyaluronic acid and proteoglycan accumulation in the cumulus oophorus matrix.

A factor produced by the oocytes induces in vitro FSH-treated cumulus and mural granulosa cells to synthesize hyaluronic acid. In the present study we examined hyaluronic acid synthesis by the two cell populations in vivo. After injection of hCG into PMSG-primed immature mice, cumulus and mural granulosa cells adjacent to the antrum synthesized a large amount of such glycosaminoglycan, while the outermost layers layers of mural granulosa cells did not. The results suggest that in vivo differences in hyaluronic acid synthesis between follicle cell subpopulations depend on a diffusion gradient of the oocyte factor. We also identified a proteoglycan species synthesized by cumulus cells which may contribute to hyaluronic acid organization in the intercellular spaces.