Octreotide alleviates obesity by reducing intestinal glucose absorption and inhibiting low-grade inflammation

Abstract

To investigate the role of octreotide, a somatostatin (SST) analog with anti-inflammatory effects, on the digestive and absorptive functions of jejunum in rats fed a high-fat diet, as well as its therapeutic prospects for diet-induced obesity. Rats were divided into three groups with different diet and treatment for the 176-day experiment: (1) control, 18 rats fed with standard chow, (2) high-fat control, 19 rats fed with high-fat chow, and (3) high-fat octreotide, 21 rats fed with high-fat chow and treated with octreotide for the last 8 days of the experiment. Plasma tumor necrosis factor-α (TNF-α) was measured by ELISA and SST by radioimmunoassay. Disaccharidase activity in the jejunal homogenate was determined. SST and Na⁺-dependent glucose transporter 1 (SGLT-1) in the jejunal mucosa were visualized by immunohistochemistry. SGLT-1 was quantified by reverse transcription polymerase chain reaction and Western blot assays. After 176 days, the fat/body weight ratio, villus height, maltase, SGLT-1, and plasma TNF-α in the high-fat control rats were much higher than those in the control rats (p < 0.01 or p < 0.05) and were significantly lower in the high-fat + octreotide rats (p < 0.01 or p < 0.05). SST levels were dramatically different in the intestinal mucosa of the two high-fat groups (231.12 ± 98.18 pg/mg in the high-fat controls and 480.01 ± 286.65 pg/mg in the octreotide group). The low-grade inflammation induced by high-fat diet apparently reduced the secretion of intestinal SST, which increased intestinal absorption of energy and nutrients and formation of adipose tissues. Octreotide effectively reversed this process, a finding that has far-reaching significance for the regulation of energy balance.