Mediates the Na(+)-independent uptake of organic anions (PubMed:10779507, PubMed:15159445, PubMed:17412826). Shows broad substrate specificity, can transport both organic anions such as bile acid taurocholate (cholyltaurine) and conjugated steroids (17-beta- glucuronosyl estradiol, dehydroepiandrosterone sulfate (DHEAS), and estrone 3-sulfate), as well as eicosanoid leukotriene C4, prostaglandin E2 and L-thyroxine (T4) (PubMed:10779507, PubMed:11159893, PubMed:12568656, PubMed:15159445, PubMed:17412826, PubMed:19129463). Hydrogencarbonate/HCO3(-) acts as the probable counteranion that exchanges for organic anions (PubMed:19129463). Shows a pH-sensitive substrate specificity towards sulfated steroids, taurocholate and T4 which may be ascribed to the protonation state of the binding site and leads to a stimulation of substrate transport in an acidic microenvironment (PubMed:19129463). Involved in the clearance of bile acids and organic anions from the liver (PubMed:22232210). Can take up bilirubin glucuronides from plasma into the liver, contributing to the detoxification-enhancing liver-blood shuttling loop (PubMed:22232210). Transports coproporphyrin I and III, by-products of heme synthesis, and may be involved in their hepatic disposition (PubMed:26383540). May contribute to regulate the transport of organic compounds in testes across the blood-testis-barrier (Probable). Can transport HMG-CoA reductase inhibitors (also known as statins) such as pitavastatin, a clinically important class of hypolipidemic drugs (PubMed:15159445). May play an important role in plasma and tissue distribution of the structurally diverse chemotherapeutic drugs methotrexate and paclitaxel (PubMed:23243220). May also transport antihypertension agents, such as the angiotensin-converting enzyme (ACE) inhibitor prodrug enalapril, and the highly selective angiotensin II AT1-receptor antagonist valsartan, in the liver (PubMed:16624871, PubMed:16627748). {ECO:0000269|PubMed:10779507, ECO:0000269|PubMed:11159893, ECO:0000269|PubMed:12568656, ECO:0000269|PubMed:15159445, ECO:0000269|PubMed:16624871, ECO:0000269|PubMed:16627748, ECO:0000269|PubMed:17412826, ECO:0000269|PubMed:19129463, ECO:0000269|PubMed:22232210, ECO:0000269|PubMed:23243220, ECO:0000269|PubMed:26383540, ECO:0000305|PubMed:35307651}. This is the function of SLCO1B3 (solute carrier organic anion transporter family member 1B3, Ensembl gene identifier ENSG00000111700).