Duodenal-jejunal bypass restores insulin action and I'eta-cell function in hypothalamic-obese rats

Abstract

Bariatric operations are frequently used to improve metabolic profile and comorbidities in obese subjects, but the effects of this procedure in hypothalamic-obese (HyO) patients are controversial. Here, using HyO rats, we investigate the effects of duodenal-jejunal bypass (DJB) upon obesity, serum lipid levels, glucose tolerance, and insulin action and secretion. Hypothalamic obesity was induced in male rats by the administration of monosodium glutamate [4 g/kg body weight (BW), HyO group] during the first 5 days of life. Control (CTL) group received saline (1.25 g/kg BW). At 90 days of age, HyO rats were submitted to DJB (HyO DJB group) or sham surgery. After 2 months, lipid levels, glucose tolerance, obesity parameters, and insulin sensitivity and secretion were verified. HyO rats displayed obesity, hypertriglyceridemia, hypercholesterolemia, glucose intolerance, and hyperinsulinemia. A higher HOMA-IR and no alteration in the ratio of phospho (p)-Akt related to Akt protein content in the liver, after insulin stimulus, demonstrated that HyO rats were insulin resistant. Islets isolated from HyO rats hypersecreted insulin in response to glucose and carbachol (Cch). At 2 months after DJB, HyO rats still displayed higher fat stores, but showed normal serum lipids and insulin levels. The HyO DJB group displayed better glucose tolerance, associated with a normal hepatic insulin activation of Akt. Normal glucose and Cch-induced insulin secretion was observed in HyO DJB islets. DJB ameliorated glucose homeostasis, restored hepatic insulin action, and normalized islet function in HyO rats, indicating that this surgery may be useful for the treatment of hypothalamic obesity