Effect of TBT exposure on mRNA expression in pre-luteinized and luteinized ovine primary theca cells. mRNA expression (mean ± SEM) of cholesterol transport factors (TSPO, LDLR, SR-B1, ABCA1) and cholesterol biosynthesis factors (HSL, CREB1, SREBF1) in primary ovine pre-luteinized (A) and luteinized (B) ovine primary theca cells exposed to 1 ng/ml TBT (gray bars), 10 ng/ml TBT (closed bars) or vehicle (control group; open bars). Asterisks denote differences among treatments (P < 0.05). N=3 primary cultured cell lines per group.