Protzek AOP, Rezende LF, Costa-Júnior JM, Ferreira SM, Cappelli APG, de Paula FMM, de Souza JC, Kurauti MA, Carneiro EM, Rafacho A, Boschero AC. Hyperinsulinemia caused by dexamethasone treatment is associated with reduced insulin clearance and lower hepatic activity of insulin-degrading enzyme.
J Steroid Biochem Mol Biol 2016;
155:1-8. [PMID:
26386462 DOI:
10.1016/j.jsbmb.2015.09.020]
[Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/10/2015] [Accepted: 09/12/2015] [Indexed: 01/25/2023]
Abstract
OBJECTIVES
Glucocorticoid treatment induces insulin resistance (IR), which is counteracted by a compensatory hyperinsulinemia, due to increased pancreatic β-cell function. There is evidence for also reduced hepatic insulin clearance, but whether this correlates with altered activity of insulin-degrading enzyme (IDE) in the liver, is not fully understood. Here, we investigated whether hyperinsulinemia, in glucocorticoid-treated rodents, is associated with any alteration in the insulin clearance and activity of the IDE in the liver.
MATERIALS/METHODS
Adult male Swiss mice and Wistar rats were treated with the synthetic glucocorticoid dexamethasone intraperitoneally [1mg/kg body weight (b.w.)] for 5 consecutive days.
RESULTS
Glucocorticoid treatment induced IR and hyperinsulinemia in both species, but was more impactful in rats that also displayed glucose intolerance and hyperglycemia. Insulin clearance was reduced in glucocorticoid-treated rats and mice, as judged by the reduction of insulin decay rate and increased insulin area-under-the-curve (47% and 87%, respectively). These results were associated with reduced activity (35%) of hepatic IDE in rats and a tendency to reduction (p=0.068) in mice, without alteration in hepatic IDE mRNA content, in both species.
CONCLUSION
In conclusion, the reduced insulin clearance in glucocorticoid-treated rodents was due to the reduction of hepatic IDE activity, at least in rats, which may contributes to the compensatory hyperinsulinemia. These findings corroborate the idea that short-term and/or partial inhibition of IDE activity in the liver could be beneficial for the glycemic control.
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