- Tytuł:
- Spectrophotometric assay of renal ouabain-resistant Na+-ATPase and its regulation by leptin and dietary-induced obesity.
- Autorzy:
-
Bełtowski, Jerzy
Jamroz-Wiśniewska, Anna
Nazar, Jarosław
Wójcicka, Grażyna - Powiązania:
- https://bibliotekanauki.pl/articles/1041514.pdf
- Data publikacji:
- 2004
- Wydawca:
- Polskie Towarzystwo Biochemiczne
- Tematy:
-
leptin
obesity
Na+,K+-ATPase
Na+-ATPase - Opis:
- Apart from Na+,K+-ATPase, a second sodium pump, Na+-stimulated, K+-independent ATPase (Na+-ATPase) is expressed in proximal convoluted tubule of the mammalian kidney. The aim of this study was to develop a method of Na+-ATPase assay based on the method previously used by us to measure Na+,K+-ATPase activity (Acta Biochim Polon.; 2002, 49: 515-27). The ATPase activity was assayed as the amount of inorganic phosphate liberated from ATP by isolated microsomal fraction. Na+-ATPase activity was calculated as the difference between the activities measured in the presence and in the absence of 50 mM NaCl. Na+-ATPase activity was detected in the renal cortex (3.5 ± 0.2 μmol phosphate/h per mg protein), but not in the renal medulla. Na+-ATPase was not inhibited by ouabain or an H+,K+-ATPase inhibitor, Sch 28080, but was almost completely blocked by 2 mM furosemide. Leptin administered intraperitoneally (1 mg/kg) decreased the Na+,K+-ATPase activity in the renal medulla at 0.5 and 1 h by 22.1% and 27.1%, respectively, but had no effect on Na+-ATPase in the renal cortex. Chronic hyperleptinemia induced by repeated subcutaneous leptin injections (0.25 mg/kg twice daily for 7 days) increased cortical Na+,K+-ATPase, medullary Na+,K+-ATPase and cortical Na+-ATPase by 32.4%, 84.2% and 62.9%, respectively. In rats with dietary-induced obesity, the Na+,K+- ATPase activity was higher in the renal cortex and medulla by 19.7% and 34.3%, respectively, but Na+-ATPase was not different from control. These data indicate that both renal Na+-dependent ATPases are separately regulated and that up-regulation of Na+-ATPase may contribute to Na+ retention and arterial hypertension induced by chronic hyperleptinemia.
- Źródło:
-
Acta Biochimica Polonica; 2004, 51, 4; 1003-1014
0001-527X - Pojawia się w:
- Acta Biochimica Polonica
- Dostawca treści:
- Biblioteka Nauki
Artykuł