Brief Article
Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Oct 21, 2011; 17(39): 4434-4439
Published online Oct 21, 2011. doi: 10.3748/wjg.v17.i39.4434
Effects of octreotide on glucose transporter type 2 expression in obese rat small intestine
Na Wei, Rui Liu, Yan Ou, Xian Li, Ou Qiang, Wei Guo, Cheng-Wei Tang
Na Wei, Rui Liu, Yan Ou, Xian Li, Ou Qiang, Wei Guo, Cheng-Wei Tang, Division of Peptides Related to Human Disease, National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
Na Wei, Yan Ou, Cheng-Wei Tang, Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
Author contributions: Liu R and Tang CW developed the concept of the study; Liu R participated in its design and coordination, applied for funding; The majority of experiments were performed by Ou Y, Li X, Qiang O, Guo W and Wei N; Wei N analyzed the data, wrote the manuscript; and Liu R revised the manuscript; All authors read and approved the final manuscript.
Supported by Grants from the National Natural Sciences Foundation of China, No. 30870919; Sichuan Provincial Department of Science and Technology, No. 2010SZ0176
Correspondence to: Dr. Rui Liu, Division of Peptides Related to Human Disease, National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China. lrui60@yahoo.com.cn
Telephone: +86-28-85164011 Fax: +86-28-85164013
Received: February 14, 2011
Revised: April 5, 2011
Accepted: April 12, 2011
Published online: October 21, 2011
Abstract

AIM: To investigate the effects of the somatostatin analogue, octreotide, on maltose and sucrase activities and expression of glucose transporter type 2 (GLUT2) in obese rat intestinal mucosa.

METHODS: We divided 49 Sprague-Dawley rats into a group of 31 high fat diet-induced obese rats and a group of 18 normal controls. The obese rats were separated into an octreotide treated group of 16 rats and an obese group of 15. The intervention group was injected with octreotide at 40 μg/kg body weight every 12 h for 8 d. Rat body weight was measured weekly to calculate Lee’s index. After euthanization, maltase and sucrase activities in the small intestine were measured by activity assays, and the fasting plasma glucose level was measured. The expression of GLUT2 in small intestinal mucosa was analyzed by immunohistochemistry, reverse transcriptase polymerase chain reaction and Western blotting assays.

RESULTS: Body weight, Lee’s index, fasting plasma glucose level, maltase activity in small intestinal mucosa, mucosa and apical GLUT2, GLUT2 mRNA and protein expression levels were all significantly higher in the obese group than in the normal control group (605.61 ± 141.00 vs 378.54 ± 111.75, 337.61 ± 10.82 vs 318.73 ± 20.10, 8.60 ± 1.38 vs 7.33 ± 0.70, 156.01 ± 58.81 vs 50.43 ± 30.49, 390 744.2 ± 62 469.21 vs 170 546.50 ± 50 646.14, 26 740.18 ± 3809.60 vs 354.98 ± 57.19, 0.26 ± 0.11 vs 0.07 ± 0.02, and 2.08 ± 0.59 vs 1.27 ± 0.38, respectively, all P < 0.01). Sucrase activity did not differ between the two groups. Octreotide intervention significantly decreased the body weight and fasting plasma glucose level of obese rats (508.27 ± 94.39 vs 605.61 ± 141.00, 7.58 ± 1.51 vs 8.60 ±1.38, respectively, all P < 0.05). The intestinal mucosa and apical GLUT2, expression of GLUT2 mRNA and protein were also significantly lower in the octreotide intervention group than in the obese group (269 975.2 ± 53 730.94 vs 390 744.2 ± 62 469.21, 3758.06 ±364.51 vs 26 740.18 ± 3809.60, 0.08 ± 0.02 vs 0.26 ±0.11, and 1.31 ± 0.27 vs 2.08 ± 0.59, respectively, all P < 0.01).

CONCLUSION: High fat diet-induced obesity is associated with elevated intestinal maltase activity, GLUT2 expression, and permanent apical GLUT2 in the small intestinal mucosa of rats. Octreotide can inhibit these effects.

Keywords: Glucose transporter type 2, High fat diet, Maltase, Obesity, Octreotide, Rat, Small intestinal absorption