Favaro VF, Oshiro-Monreal FM, de Bragança AC, Andrade L, Seguro AC, Helou CMB. High cholesterol feeding may induce tubular dysfunction resulting in hypomagnesemia.
Kidney Blood Press Res 2011;
35:137-46. [PMID:
22104091 DOI:
10.1159/000332399]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 08/28/2011] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND/AIMS
Hypomagnesemia may induce hypercholesterolemia, but the contrary has not been described yet. Thus, magnesium homeostasis was evaluated in rats fed a cholesterol-enriched diet for 8 days. This study has a relevant clinical application if hypomagnesemia, due to hypercholesterolemia, is confirmed in patients with long-term hypercholesterolemia.
METHODS
Both hypercholesterolemic (HC) and normocholesterolemic rats (NC) were divided into sets of experiments to measure hemodynamic parameters, physiological data, maximum capacity to dilute urine (C(H)((2))(O)), variations (Δ) in [Ca(2+)](i) and the expression of transporter proteins.
RESULTS
HC developed hypomagnesemia and showed high magnesuria in the absence of hemodynamic abnormalities. However, the urinary sodium excretion and C(H)((2))(O) in HC was similar to NC. On the other hand, the responses to angiotensin II by measuring Δ [Ca(2+)](i) were higher in the thick ascending limb of Henle's loop (TAL) of HC than NC. Moreover, high expression of the cotransporter NKCC2 was found in renal outer medulla fractions of HC. Taken together, the hypothesis of impairment in TAL was excluded. Actually, the expression of the epithelial Mg(2+) channel in renal cortical membrane fractions was reduced in HC.
CONCLUSION
Impairment in distal convoluted tubule induced by hypercholesterolemia explains high magnesuria and hypomagnesemia observed in HC.
Collapse