REDUCED RATE OF ADIPOSE TISSUE GROWTH AND LIPID ACCUMULATION IN MICE SELECTED FOR HIGH BODY WEIGHT

To elucidate the influence of high body weight selection on tissue growth patterns, adipose tissue growth and lipid accumulation were investigated in both a line of mice selected for high 42-day body weight (High line; HL-3) and an unselected (Foundation; FP-3) population. All comparisons between the two lines were performed on a within-sex basis. Logistic growth curve analysis revealed that HL-3 mice exhibited an accelerated growth rate, and reached a higher mature body weight, than FP-3 mice. Employing the allometric equation, Y = aXb, this investigation further revealed that, relative to both body weight and nonadipose tissue weight, adipose tissue and extractable lipid increased slower in HL-3 mice than in FP-3 mice. Only at fixed body and nonadipose tissue weights, which exceeded the maximum weights achieved by the FP-3, did HL-3 adipose tissue and lipid weights exceed those of FP-3 mice. HL-3 mice have previously been demonstrated to exhibit an increased appetite. Therefore, the existing model of selection-mediated compositional changes should be expanded to allow the coupling of an increased appetite with an enhanced relative rate of nonfat tissue growth. Key words: Growth-selected mice, adipose tissue growth, lipid accumulation