The Sulfatase Pathway for Estrogen Formation: Targets for the Treatment and Diagnosis of Hormone-Associated Tumors

Figure 2

Uptake of E1S from the blood by organic anion transporting polypeptides (OATPs) and other SLC-Transporters. Biotransformation is mediated by phase 1 biotransformation (cytochrome P450 and isoenzymes) and phase 2 biotransformation (sulfotransferase and sulfatase). The excretion of sulfated estrogens is achieved by the breast cancer resistant protein (BCRP, ABCG2) and multidrug resistance related proteins (MRPs). Uptake, biotransformation and excretion is transcriptionally regulated by nuclear receptors, for example, the pregnane X receptor (PXR), which acts as a xenobiotic-activated transcription factor.