Effects of hypoxic and normoxic conditions and of different cell plating density on transcript abundance in cultured bovine granulosa cells. The expression of GAPDH (a), B2M (b), TBP (c), HMBS (d), RPS18 (e), RPLP0 (f) and HPRT1 (g) was analyzed under hypoxic (5% O2) and normoxic conditions (20% O2) at low and high cell plating density. Copy numbers were calculated and normalized to initial amounts of RNA used for cDNA preparation. Values are means ± SEMs of three independent cultures. Bars with different letters are significantly different from each other.