title: Uric acid metabolism of kidney and intestine in a rat model of chronic kidney disease.
abstract: Uric acid (UA) is a potential risk factor of the progression of chronic kidney disease (CKD). Recently, we reported that intestinal UA excretion might be enhanced via upregulation of the ATP-binding cassette transporter G2 (Abcg2) in a 5/6 nephrectomy (Nx) rat model. In the present study, we examined the mRNA and protein expressions of UA transporters, URAT1, GLUT9/URATv1, ABCG2 and NPT4 in the kidney and ileum in the same rat model. Additionally, we investigated the Abcg2 mRNA expression of ileum in hyperuricemic rat model by orally administering oxonic acid. Male Wistar rats were randomly assigned to three groups consisting of Nx group, oxonic acid-treated (Ox) group and sham-operated control group, and sacrificed at 8 weeks. Creatinine and UA were measured and the mRNA expressions of UA transporters in the kidney and intestine were evaluated by a real time PCR. UA transporters in the kidney sections were also examined by immunohistochemistry. Serum creatinine elevated in the Nx group whereas serum UA increased in the Ox group. Both the mRNA expression and the immunohistochemistry of the UA transporters were decreased in the Nx group, suggesting a marginal role in UA elevation in decreased kidney function. In contrast, the mRNA expression of Abcg2 in the ileum significantly increased in the Ox group. These results suggest that the upregulation of Abcg2 mRNA in the ileum triggered by an elevation of serum UA may play a compensatory role in increasing intestinal UA excretion.
authors.affiliation: a Department of Internal Medicine , Teikyo University School of Medicine , Tokyo , Japan.
authors.forename: Michito
authors.initials: M
authors.lastname: Nagura
authors.affiliation: a Department of Internal Medicine , Teikyo University School of Medicine , Tokyo , Japan.
authors.forename: Yoshifuru
authors.initials: Y
authors.lastname: Tamura
authors.affiliation: a Department of Internal Medicine , Teikyo University School of Medicine , Tokyo , Japan.|b Support for Community Medicine Endowed Chair, Teikyo University School of Medicine , Tokyo , Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kumagai
authors.affiliation: c Human Physiology and Pathology, Faculty of Pharma Sciences, Teikyo University , Tokyo , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hosoyamada
authors.affiliation: a Department of Internal Medicine , Teikyo University School of Medicine , Tokyo , Japan.
authors.forename: Shunya
authors.initials: S
authors.lastname: Uchida
mesh_terms: D000818:Animals; D003106:Colon / Q000378:metabolism; D003404:Creatinine / Q000097:blood; D004386:Duodenum / Q000378:metabolism; D015870:Gene Expression; D007082:Ileum / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008297:Male; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar; D051436:Renal Insufficiency, Chronic / Q000097:blood*; D014527:Uric Acid / Q000097:blood*
chemical_list: D027361:Organic Anion Transporters; D012333:RNA, Messenger; C103862:urate transporter; D014527:Uric Acid; D003404:Creatinine
keywords: ABCG2; Chronic kidney disease; creatinine clearance; intestinal uric acid excretion; oxonic acid; remnant kidney model; urate transporter