Protein abundance of urea transporters and aquaporin 2 change differently in nephrotic pair-fed vs. non-pair-fed rats
| Autor: | Christopher F. Martin, Douglas C. Eaton, Jeff M. Sands, Raed N. Bou Matar, Janet D. Klein, Xiaonan H. Wang, Bela Malik |
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| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Male
medicine.medical_specialty Glycosylation Nephrotic Syndrome Sodium-Hydrogen Exchangers Physiology Sodium-Potassium-Chloride Symporters Nephrosis Kidney Rats Sprague-Dawley chemistry.chemical_compound Eating Focal segmental glomerulosclerosis Internal medicine medicine Animals Epithelial Sodium Channels Aquaporin 2 Chemistry urogenital system Kidney metabolism Membrane Transport Proteins Transporter Articles medicine.disease Rats Proteinuria Endocrinology Biochemistry Urea Cotransporter Nephrotic syndrome |
| Popis: | Salt and water retention is a hallmark of nephrotic syndrome (NS). In this study, we test for changes in the abundance of urea transporters, aquaporin 2 (AQP2), Na-K-2Cl cotransporter 2 (NKCC2), and Na-Cl cotransporter (NCC), in non-pair-fed and pair-fed nephrotic animals. Doxorubicin-injected male Sprague-Dawley rats ( n = 10) were followed in metabolism cages. Urinary excretion of protein, sodium, and urea was measured periodically. Kidney inner medulla (IM), outer medulla, and cortex tissue samples were dissected and analyzed for mRNA and protein abundances. At 3 wk, all doxorubicin-treated rats developed features of NS, with a ninefold increase in urine protein excretion (from 144 ± 21 to 1,107 ± 165 mg/day; P < 0.001) and reduced urinary sodium excretion (from 0.17 to 0.12 meq/day; P < 0.001). Urine osmolalities were reduced in the nephrotic animals (1,057 ± 37, treatment vs. 1,754 ± 131, control). Unlike animals fed ad libitum, UT-A1 protein abundance was unchanged in nephrotic pair-fed rats. Glycosylated AQP2 was reduced in the IM base of both nephrotic groups. Abundances of NKCC2 and NCC were consistently reduced (71 ± 7 and 33 ± 13%, respectively) in both nephrotic pair-fed animals and animals fed ad libitum. In pair-fed nephrotic rats, we observed an increase in the cleaved form of membrane-bound γ-epithelial sodium channel (ENaC). However, α- and β-ENaC subunits were unaltered. NKCC2 and AQP2 mRNA levels were similar in treated vs. control rats. We conclude that dietary protein intake affects the response of medullary transport proteins to NS. |
| Databáze: | OpenAIRE |
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