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ARS Home » Southeast Area » Little Rock, Arkansas » Arkansas Children's Nutrition Center » Research » Publications at this Location » Publication #213655
Title: Increased adipocyte de nova lipogenesis underlies high carbohydrate driven obesity: Role for ChREBP

Author
item SHANKAR, KARTIK - ACNC/UAMS
item HARRELL, AMANDA - ACNC
item LIU, XIAOLI - ACNC/UAMS
item RONIS, MARTIN - ACNC/UAMS
item BADGER, THOMAS - ACNC/UAMS

Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2007
Publication Date: 4/28/2007
Citation: Shankar, K., Harrell, A., Liu, X., Ronis, M.J., Badger, T.M. 2007. Increased adipocyte de nova lipogenesis underlies high carbohydrate driven obesity: Role for ChREBP [abstract]. The FASEB Journal. 21(5):A693.

Interpretive Summary: Fat can be deposited in the body from excess caloric intake. Many people think that it is the fatty foods that cause obesity, and in some cases this is true. However, this increase in fat stores can occur from all types of foods, including protein rich foods (even pure protein) and carbohydrate rich foods (even fruits). The current study demonstrated how carbohydrates can alter the metabolism of rats to produce fat stores that lead to obesity. These are important data that we hope to use to prevent childhood obesity in the future.

Technical Abstract: Dietary macronutrient composition has important consequences for overall body weight gain and adiposity. Using a total enteral nutrition (TEN) model we have previously shown that low fat/high-carbohydrate diets are more obesegenic than high-fat diets under conditions of equal caloric intake. In the present studies, we evaluate the underlying mechanisms of high carbohydrate driven obesity. Female Sprague-Dawley rats were fed 187 kcal/kg3/4/d (NRC requirements) or 220 kcal/kg3/4/d (15% excess calories/d) via entragastric infusion. Diets were either low fat/high carbohydrate (HC, 75% carbohydrate calories and 5% fat calories) or high fat (HF, 45% fat calories). HC and HF diets were isocaloric. Rats fed HC diets at both 187 and 220 Keal, gained approx. 114 and 119% greater body weights and approx. 250 and 190% greater %body fat/body weight than HF conterparts during three weeks of diets. HC fed rats also showed hyperleptinemia and increased insulin resistance (p < 0.05). Histomorphometric analyses of adipose tissue sections revealed approx. 2.5- and 5-fold increase in the % of 100 'm or larger adipocytes, in 187 and 220 Kcal fed rats, respectively, indicating increased hypertrophy of adipocytes. Immunoblot analyses of adipose tissue lysates revealed greater fatty acid synthase (FAS) and acyl-CoA carboxylase expression in the HC fed groups, suggesting increased “de novo” lipogenesis following HC consumption. Increased lypogenic protein expression was also associated with greater nuclear levels of carbohydrate-response element binding protein (ChREBP) in HC fed rats. Analysis of in vivo ChREBP recruitment to FAS promoter in HC-fed rats using ChIP is ongoing.