Mediates the transport of prostaglandins (PGs, mainly PGE2, PGE1, PGE3, PGF2alpha, PGD2, PGH2) and thromboxanes (thromboxane B2) across the cell membrane. PGs and thromboxanes play fundamental roles in diverse functions such as intraocular pressure, gastric acid secretion, renal salt and water transport, vascular tone, and fever. Plays a role in the clearance of PGs from the circulation through cellular uptake, which allows cytoplasmic oxidation and PG signal termination. PG uptake is dependent upon membrane potential and involves exchange of a monovalent anionic substrate (PGs exist physiologically as an anionic monovalent form) with a stoichiometry of 1:1 for divalent anions or of 1:2 for monovalent anions. Uses lactate, generated by glycolysis, as a counter-substrate to mediate PGE2 influx and efflux. Under nonglycolytic conditions, metabolites other than lactate might serve as counter-substrates. Although the mechanism is not clear, this transporter can function in bidirectional mode. When apically expressed in epithelial cells, it facilitates transcellular transport (also called vectorial release), extracting PG from the apical medium and facilitating transport across the cell toward the basolateral side, whereupon the PG exits the cell by simple diffusion. In the renal collecting duct, regulates renal Na+ balance by removing PGE2 from apical medium (PGE2 EP4 receptor is likely localized to the luminal/apical membrane and stimulates Na+ resorption) and transporting it toward the basolateral membrane (where PGE2 EP1 and EP3 receptors inhibit Na+ resorption). Plays a role in endometrium during decidualization, increasing uptake of PGs by decidual cells. Involved in critical events for ovulation. Regulates extracellular PGE2 concentration for follicular development in the ovaries. Expressed intracellularly, may contribute to vesicular uptake of newly synthesized intracellular PGs, thereby facilitating exocytotic secretion of PGs without being metabolized. Essential core component of the major type of large-conductance anion channel, Maxi-Cl, which plays essential roles in inorganic anion transport, cell volume regulation and release of ATP and glutamate not only in physiological processes but also in pathological processes. May contribute to regulate the transport of organic compounds in testis across the blood-testis-barrier (Probable).