Pathophysiological Changes by Short-term Food Restriction in Obese Diabetic Rats
K. Miyajima *
Japan Tobacco Inc., Central Pharmaceutical Research Institute, Osaka, Japan.
Y. Toriniwa
Japan Tobacco Inc., Central Pharmaceutical Research Institute, Osaka, Japan
Y. Motohashi
Japan Tobacco Inc., Central Pharmaceutical Research Institute, Osaka, Japan.
Y. Ishii
Japan Tobacco Inc., Central Pharmaceutical Research Institute, Osaka, Japan.
M. Shinohara
CLEA Japan Inc., Planning and Development Section, Tokyo, Japan
H. Yamashiro
Laboratory of Animal Reproduction, Faculty of Agriculture, Niigata University, Niigata, Japan.
T. Yamada
Laboratory of Animal Genetics, Graduate School of Science and Technology, Niigata University, Niigata, Japan.
T. Ohta
Japan Tobacco Inc., Central Pharmaceutical Research Institute, Osaka, Japan and Laboratory of Animal Genetics, Graduate School of Science and Technology, Niigata University, Niigata, Japan.
*Author to whom correspondence should be addressed.
Abstract
Aim: Reduced calorie intake by food restriction leads to extension of life span by exerting beneficial effects on metabolism. Zucker diabetic fatty (ZDF) rat is a type 2 diabetic model with obesity, showing the incidence of diabetes after 7 weeks of age. The present study investigated effects of 2-week food restriction on the pancreas in ZDF rats.
Methods: ZDF rats were pair-fed with Zucker lean (ZL) rats from 7 to 9 weeks of age (The amount of food in ZDF rats was calculated based on the daily food consumption in ZL rats). Body weight and biochemical parameters such as serum glucose, triglyceride, total cholesterol, non-esterified fatty acid and insulin levels, were evaluated. After necropsy, islet size and insulin content in pancreas were measured.
Results: The ZDF rats showed increased blood glucose, insulin and lipid levels at 7 weeks as compared with those in ZL rats. After food restriction for 2 weeks, the blood glucose, insulin, and triglyceride levels in pair-fed ZDF rats were decreased. The islet size in pair-fed ZDF rats decreased as compared with that in ad lib-fed ZDF rats, but the insulin content in pancreas of pair-fed ZDF rats increased remarkably.
Conclusion: ZDF rats showed improvement of pancreatic disorders by food restriction. Caloric restriction applied at an insulin resistant pre-diabetic stage is an effective means for preventing the pancreatic disorder in diabetes with obesity.
Keywords: Food restriction, pancreas, ZDF rat.