OCTN

Novel Organic Cation Transporter Family (OCTN) 

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Organic cation transporters OCTs (3), OCTNs (3) SLC22A... 

George-Hyslop, and K. A. Siminovitch. Functional variants of OCTN cation transporter genes are associated with Crohn disease. Nat Genet 36 471 —475 (2004). 

Novel organic cation OCTN OCTN2 SLC22A4 SLC22A5 Luminal Abluminal Blood to endothelium Organic cation/proton exchange... 

The novel organic cation transporters (OCTNs) represent a subfamily of OCTs with only 30% amino acid sequence similarity to the OCTs. Two members have been identified. 

After 3 months of therapy (Table 9-1), serum levels of carnitine, though still lower than the controls, had increased markedly from the pretherapy levels. Muscle carnitine levels also increased but remained well below normal. Despite this, clinical muscle strength and tone were remarkably improved. Carnitine levels in the liver (where carnitine transport is not dependent on OCTN-2) increased more dramatically than those in muscle. Despite the low serum carnitine concentration, urinary carnitine losses were dramatically increased in the patient while on therapy as compared with controls. This reflects the continued dysfunction of the renal OCTN-2 and thus the continued urinary wasting of carnitine. 

OCTN organic cation/carnitine transporter PSS progressive systemic sclerosis... 

OCTN 1 and OCTN2 (SLC22A4, SLC22A5) are expressed in human kidney, with OCTN2 also showing high expression in the small intestine [25]. In kidney both transporters are localized in the apical membrane of proximal tubules, whereas in intestine OCTN2 is localized in the brush border membrane of enterocytes. There it... 

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