Hypertension Research Today is a free monthly online journal that collates and summarizes the latest research about Hypertension, including details on symptoms, diagnosis, diet, treatment, causes.

Resistance of mice lacking the serum- and glucocorticoid-inducible kinase SGK1 against salt-sensitive hypertension induced by a high-fat diet.

Huang DY, Boini KM, Osswald H, Friedrich B, Artunc F, Ullrich S, Rajamanickam J, Palmada M, Wulff P, Kuhl D, Vallon V, Lang F

Department of Pharmacology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany.

Mineralocorticoids enhance expression and insulin stimulates activity of the serum- and glucocorticoid-inducible kinase SGK1, which activates the renal epithelial Na+)channel (ENaC). Under a salt-deficient diet, SGK1 knockout mice (sgk1-/-) excrete significantly more NaCl than their wild-type littermates (sgk1+/+) and become hypotensive. The present experiments explored whether SGK1 participates in the hypertensive effects of a high-fat diet and high-salt intake. Renal SGK1 protein abundance of sgk1+/+ mice was significantly elevated after a high-fat diet. Under a control diet, fluid intake, blood pressure, urinary flow rate, and urinary Na+, K+, and Cl- excretion were similar in sgk1-/- and sgk1+/+ mice. Under a standard diet, high salt (1% NaCl in the drinking water for 25 days) increased fluid intake, urinary flow rate, and urinary Na+, K+, and Cl- excretion similarly in sgk1-/- and sgk1+/+ mice without significantly altering blood pressure. A high-fat diet alone (17 wk) did not significantly alter fluid intake, urinary flow rate, urinary Na+, K+, or Cl- excretion, or plasma aldosterone levels but increased plasma insulin, total cholesterol, triglyceride concentrations, and systolic blood pressure to the same extent in both genotypes. Additional salt intake (1% NaCl in the drinking water for 25 days) on top of a high-fat diet did not affect hyperinsulinemia or hyperlipidemia but increased fluid intake, urinary flow rate, and urinary NaCl excretion significantly more in sgk1-/- than in sgk1+/+ mice. Furthermore, in animals receiving a high-fat diet, additional salt intake increased blood pressure only in sgk1+/+ mice (to 132 +/- 3 mmHg) but not in sgk1-/- mice (120 +/- 4 mmHg). Thus lack of SGK1 protects against the hypertensive effects of a combined high-fat/high-salt diet.

Published 3 November 2006 in Am J Physiol Renal Physiol, 291(6): F1264-73.
Full-text of this article is available online (may require subscription).

© 2004-2008 Hypertension Research Today. All Rights Reserved.