Estrogens and selective estrogen receptor modulators regulate gene and protein expression in the mesenteric arteries

Estrogen is a reproductive steroid hormone that has both beneficial and detrimental effects on the cardiovascular system. Selective estrogen receptor modulators (SERMs) exhibit partial estrogen agonist/antagonist activity in estrogen target tissues. Since we still have an incomplete picture of the gene targets of estrogen in the vasculature, and our understanding of SERM gene targets in the vasculature is even less well-developed, it is important to broaden the available information on this subject. The present study tested the hypothesis that estrogens (ethinyl estradiol, estradiol benzoate, and equilin) and SERMs (tamoxifen and raloxifene) cause differential gene and protein expression in the vasculature. DNA microarray and real-time RT-PCR were used to investigate gene expression in the mesenteric arteries of estrogen and SERM treated ovariectomized rats. The genes shown to be differentially expressed included stearoyl-CoA desaturase (SCD), soluble epoxide hydrolase (sEH), secreted frizzled related protein-4 (SFRP-4), insulin-like growth factor-1 (IGF-1), phospholipase A2 group 1B (PLA2-G1B), and fatty acid synthase (FAS). Western blot further confirmed the differential expression of sEH, SFRP-4, FAS, and SCD protein. These results reveal that estrogens and SERMs cause differential gene and protein expression in the mesenteric artery. Consequently, the use of these agents may be associated with a unique profile of functional and structural changes in the mesenteric arterial circulation.