EPIDIDYMAL FAT DEPOT LIPOPROTEIN-LIPASE ACTIVITY IS LOWER IN ANIMALS WITH HIGH ENDOGENOUS FAT PREFERENCES

Adipose tissue lipoprotein lipase (LPL) is a key enzyme responsible fo r the clearance of circulating triglycerides and has been linked to ce rtain pathologic states such as obesity. Zn order to investigate wheth er an animal's endogenous fat-preference is associated with difference s in adipose tissue LPL, we measured enzyme activity in epididymal fat from high- and low-fat preferring rats. Utilizing a 24h ad Libitum fe eding paradigm, four groups of outbred adult male Sprague-Dawley rats were screened separately for their macronutrient preferences. Animals exhibiting high- or low-fat preferences were identified and placed bac k on standard chow. LPL activity was measured in epididymal fat under chow fed or fasted conditions. Epididymal fat LPL activity was signifi cantly less in the high-fat-preferring animals relative to the low-fat -preferring, in both the standard chow-fed state (p=0.014) and fasted (p=0.0007) state. LPL activity in heart ventricle and brown adipose ti ssue was also measured from the same animals. Activity in heart ventri cle and brown adipose tissue was significantly lower in the high-fat-p referring group as compared with the low-fat-preferring only following a 24h fast (p=0.0012 for heart and p=0.0085 for brown adipose, high- versus low-fat preferring). The data indicate that differences in tiss ue LPL activity exist between animals with inherent differences in fat preference. Future comparative studies between the two groups of fat- preferring animals could lead to important clues to the regulation of the LPL.