Determining the Effect of Dietary Carbohydrate Type, Glycemic Index, and NIDDM on Brown Adipose Tissue Hypertophy and Function in SHR/Ntul//-cp RAT

The present study highlights the effect of Dietary Carbohydrate Type, Glycemic Index, and NIDDM on Brown Adipose Tissue Hypertophy and Function in the SHR/Ntul//-cp RAT. Lean and obese-NIDDM SHR/Ntul/cp rats were divided into groups and given nutritionally complete isoenergetic diets containing 54% CHO as cooked cornstarch (low glycemic index, LGI diet) or the same diets plus substituting sucrose for cornstarch (S, high glycemic index, HGI diet) in order to study the effects of carbohydrate (CHO) type and NIDDM on the characteristics of interscapular Measures of blood Glucose, Insulin and the Insulin to Glucose (I:G) ratio were increased in the obese+NIDDM phenotype and further compromised in obese-NIDDM rats by HGI diet. Measures of RMR in vivo were decreased in the obese-NIDDM but increased in both lean and obese+NIDDM rats following norepinephrine administration (100 µg/kg BW, s.c.) phenotype, while isoenergetic substitution of sucrose vs cornstarch in subgroups of each phenotype resulted in modest increases in both phenotypes. Measurements of in vivo sympathetic activity, such as urine vanilmandelic acid (VMA) excretion and temperature regulation after a 4°C cold exposure, were lowered in the obese+NIDDM phenotype but only slightly improved with the isoenergetic HGI diet in both phenotypes. White adipose tissue (WAT), IBAT mass, and cellularity were all noticeably higher in obese+NIDDM animals at 10 months of age compared to lean animals. These results indicate that despite increased VO2 following exogenous administration of NE and a diet effect on VMA excretion in both phenotypes, the In vivo capacity for expression of NST is qualitatively decreased in obese+NIDDM rats, and the greater glycemic index and resulting increase in parameters of insulin resistance may be contributory factors in the magnitude of adiposity regardless of the dietary carbohydrate source. Although it remains an intriguing option for further research, it is uncertain to what extent dietary or pharmaceutical control of the obese-NIDDM sequelae might assist a restoration of thermogenic activity and processes of disturbed metabolism and caloric efficiency. One may posit that competent and clinically successful management may lessen the financial burdens on populations around the world, especially those in industrialised societies, if such measures were to be applied to those affected by them.