Details

Autor(en) / Beteiligte

• Sassen, M.C.
• Kim, S.W.
• Kwon, T.-H.
• Knepper, M.A.
• Miller, R.T.
• Frøkiær, J.
• Nielsen, S.

Titel

Dysregulation of renal sodium transporters in gentamicin-treated rats

Ist Teil von

• Kidney international, 2006-09, Vol.70 (6), p.1026-1037

Ort / Verlag

New York, NY: Elsevier Inc

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• We aimed to investigate the molecular mechanisms underlying the renal wasting of Na+, K+, Ca2+, and Mg2+ in gentamicin (GM)-treated rats. Male Wistar rats were injected with GM (40 or 80mg/kg/day for 7 days, respectively; GM-40 or GM-80). The expression of NHE3, Na–K-ATPase, NKCC2, ROMK, NCC, α-, β- and γ-ENaC, and CaSR was examined in the kidney by immunoblotting and immunohistochemistry. Urinary fractional excretion of Na+, K+, Ca2+, and Mg2+ was increased and urinary concentration was decreased in both GM-40 and GM-80 rats. In cortex and outer stripe of outer medulla (cortex) in GM-80 rats, the expression of NHE3, Na–K-ATPase, and NKCC2 was decreased; NCC expression was unchanged; and CaSR was upregulated compared to controls. In the inner stripe of outer medulla (ISOM) in GM-80 rats, NKCC2 and Na–K-ATPase expression was decreased, whereas CaSR was upregulated, and NHE3 and ROMK expression remained unchanged. In GM-40 rats, NKCC2 expression was decreased in the cortex and ISOM, whereas NHE3, Na–K-ATPase, CaSR, ROMK, and NCC abundance was unchanged in both cortex and ISOM. Immunoperoxidase labeling confirmed decreased expression of NKCC2 in the thick ascending limb (TAL) in both GM-80- and GM-40-treated rats. Immunoblotting and immunohistochemical analysis revealed increased expression of α-, β-, and γ-ENaC in cortex in GM-80 rats, but not in GM-40 rats. These findings suggest that the decrease in NKCC2 in TAL seen in response to low-dose (40mg/kg/day) gentamicin treatment may play an essential role for the increased urinary excretion of Mg2+ and Ca2+, and play a significant role for the development of the urinary concentrating defect, and increased urinary excretion of Na+ and K+. At high-dose gentamicin, both proximal and TAL sodium transporter downregulation is likely to contribute to this.