Abstract
Aims/hypothesis: Obesity is associated with aldosterone excess, hypertension and the metabolic syndrome, but the relative contribution of aldosterone to obesity-related complications is debated. We previously demonstrated that aldosterone impairs insulin secretion, and that genetic aldosterone deficiency increases glucose-stimulated insulin secretion in vivo. We hypothesised that elimination of endogenous aldosterone would prevent obesity-induced insulin resistance and hyperglycaemia. Methods: Wild-type and aldosterone synthase-deficient (As -/-) mice were fed a high-fat (HF) or normal chow diet for 12 weeks. We assessed insulin sensitivity and insulin secretion using clamp methodology and circulating plasma adipokines, and examined adipose tissue via histology. Results: HF diet induced weight gain similarly in the two groups, but As -/- mice were protected from blood glucose elevation. HF diet impaired insulin sensitivity similarly in As -/- and wild-type mice, assessed by hyperinsulinaemic-euglycaemic clamps. Fasting and glucose-stimulated insulin were higher in HF-fed As -/- mice than in wild-type controls. Although there was no difference in insulin sensitivity during HF feeding in As -/- mice compared with wild-type controls, fat mass, adipocyte size and adiponectin increased, while adipose macrophage infiltration decreased. HF feeding significantly increased hepatic steatosis and triacylglycerol content in wild-type mice, which was attenuated in aldosterone-deficient mice. Conclusions/interpretation: These studies demonstrate that obesity induces insulin resistance independently of aldosterone and adipose tissue inflammation, and suggest a novel role for aldosterone in promoting obesity-induced beta cell dysfunction, hepatic steatosis and adipose tissue inflammation.
Original language | English (US) |
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Pages (from-to) | 901-910 |
Number of pages | 10 |
Journal | Diabetologia |
Volume | 56 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2013 |
Externally published | Yes |
Keywords
- Adiponectin
- Aldosterone
- Aldosterone synthase
- Diabetes
- Fatty liver
- Insulin
- Insulin resistance
- Insulin secretion
- Renin-angiotensin-aldosterone system
ASJC Scopus subject areas
- Internal Medicine
- Endocrinology, Diabetes and Metabolism