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Octn2 ^−/− knockout mice have been characterized as a model of carnitine deficiency, resulting from a point mutation that causes a change from the amino acid leucine to arginine at residue 352. This substitution causes complete OCTN2 loss‐of‐function in vitro and in vivo. The mice, deemed juvenile visceral steatosis (jvs) mice, present with growth retardation and enlarged abdomen due to hepatic steatosis, as well as hyperammonia and hypoglycemia [94]. Pharmacokinetics in jvs mice reveal drastically altered carnitine parameters, including reduced bioavailability, decreased volume of distribution, decreased tissue‐to‐plasma concentration ratios, and increased clearance of carnitine compared with wild‐type mice [95]. Furthermore, jvs mice display spontaneous intestinal apoptotic phenotypes including ulceration and gut perforation, and an immune response involving macrophage and lymphocyte infiltration [96]. Inflammation and intestinal apoptosis are reduced when mice are treated with carnitine supplementation.