The Postprandial Thermic Effects of Diet Induced Thermogenesis in Congenic Lean and Obese LA/Ntul//-Cp Rats

The effect of phenotype on development of brown and white adipose tissue cellularity and nonshivering thermogenesis in the wistar fatty rat

“…[2][3][4] Several authors have reported fundamental aspects of the physiologic and biochemical mechanisms involved in the expression of UCP-1 activation of NST in man and animal species, which include the stimulatory effects of hyperphagia and, overnutrition during the early postweaning period, dietary macronutrient manipulation and environmental challenges on stimulating BAT growth and development. [2][3][4][5][6][7][8] These studies demonstrated that early intervention may result in increased BAT growth via both hyperplasia and hypertrophy, and once formed, the greater BAT mass and cellularity may persist and remain active well into adulthood. 7,8 The recent observations of Beige adipose tissue as an intermediate cellular type has also recently been reported by several authors, with the further suggestion that sympathetic stimulation may result in a transdifferentiation of Beige BAT into functional BAT adipocytes including the expression of the essential UCP-1 protein in the beige adipocytes.…”

“…[2][3][4][5][6][7][8] These studies demonstrated that early intervention may result in increased BAT growth via both hyperplasia and hypertrophy, and once formed, the greater BAT mass and cellularity may persist and remain active well into adulthood. 7,8 The recent observations of Beige adipose tissue as an intermediate cellular type has also recently been reported by several authors, with the further suggestion that sympathetic stimulation may result in a transdifferentiation of Beige BAT into functional BAT adipocytes including the expression of the essential UCP-1 protein in the beige adipocytes. 9 The interconversion of differentiated cell types from cells of fully differentiated tissues including BAT however may require a previously unknown epigenetic reversal were it to occur in fully terminally differentiated cells and would not only be a unique observation, but may be less convincing if it were to occur in older, more mature animals.…”

“…Measures of resting and norepinephrine stimulated thermogenesis were performed in rats after an overnight fast at 30 weeks of age via indirect calorimetry at thermal neutrality (30°C) and expressed as ml O2/kg BW -0.75 to correct for differences in body surface area between lean and obese rats as described by Kleiber and Yang et al as performed in our laboratories for many years. 7,[26][27][28][29] At 30 weeks of age rats were sacrificed by decapitation, truncal bloods collected, and principal fat depots excised in their entirety for quantification of measures of adipocyte size and number using the osmium tetroxide fixation technique for white adipose tissue and the double formalinosmium fixation methods described by Tulp et al 6,8,28 The resulting fixed adipocytes were then analyzed on a Coulter particle counter equipped with a 400 micron aperture and a C-100 channelyzer and logarithmic expander unit (Coulter Electronics, Hialeah FL USA). Tissue lipid content was determined following lipid extraction of weighed sections with the method originally described by Hirsh and Gallian.…”

A Review of Brown Adipose Tissue Development in T2DM-SHR/N-cp (Corpulent) Rats

“…20,32 While measures of metabolic rate or the thermogenic impact of exogenously adminis-tered norepinephrine were not included in the current study, norepinephrine is the neurohormone that normally innervates BAT, and the greater IBAT mass exhibited hyperplasia and hypertrophy of brown adipocytes and would be expected to demonstrate an increased capacity for NST independent of the stigmata of obesity and T2DM. [1][2][3]5 In the presence of the obese-2DM stigmata and its associated insulin resistance however the endogenous capacity for NST would likely become impaired, thereby enabling a greater efficiency of caloric utilization.…”

“…1,2 Himms-Hagen, Rothwell and Stock, and others have established the role and biochemical mechanisms of BAT-mediated thermogenesis in rats and humans, and Tulp et al established the effects of early over nutrition and of nutritional manipulation on hyperplasia and hypertrophy of brown adipose tissue in young Sprague-Dawley rats when overfed or fed calorically adequate but protein restricted diets from weaning to adolescence. [1][2][3][4][5] Once formed, the increased BAT mass and cellularity persisted well into adulthood in those studies. 6 In those early studies, the BAT mass and cellularity increased by more than 2-fold during the early post weaning period.…”