Functions as transport protein in the blood stream. Binds various hydrophobic ligands in the interior of its beta-barrel domain. Also binds synthetic drugs and influences their distribution and availability. Appears to function in modulating the activity of the immune system during the acute-phase reaction. Expressed by the liver and secreted in plasma. Synthesis is controlled by glucocorticoids, interleukin-1 and interleukin-6, It increases 5- to 50-fold upon inflammation. Contains a beta-barrel that binds various ligands in its interior. N-glycosylated. N-glycan heterogeneity at Asn-33: Hex5HexNAc4 (minor), Hex6HexNAc5 (major) and dHex1Hex6HexNAc5 (minor). Many different variants of ORM2 are known. Belongs to the calycin superfamily. Lipocalin family.