LIVER FATTY-ACID COMPOSITION CORRELATES WITH BODY-FAT AND SEX IN A MULTIGENIC MOUSE MODEL OF OBESITY

To determine whether there is altered liver lipid-fraction fatty acid distribution in a multigenic obese mouse model, we examined livers fro m eight lean (0.2-4.2% carcass fat), seven intermediate (5.7-13.8%), a nd five obese (20.2-48.7%) backcross progeny [(C57BL/6J x Mus spretus) x C57BL/6J] aged 2-3 mo. Thirteen males and seven females were fed a nonpurified stock diet. Liver lipid fractions were separated and fatty acids quantitated by thin-layer and gas chromatography. There was a s ignificant effect of obesity on 18:2 omega 6 in liver phospholipids (P L), cholesteryl esters, and triglycerides. PL 18:2 omega 6 was negativ ely correlated with carcass fat (r = -0.74, P < 0.001); 20:3 omega 6 w as elevated in FL with increased obesity (P < 0.0001), and was correla ted with carcass fat (r = 0.92, P < 0.0001); and 20:4 omega 6 in PL, d id not differ with obesity status. PL 20:3 omega 6 and 20:4 omega 6 we re lower in males (P < 0.01 and 0.02, respectively) than in females. W e conclude that obesity and sex affect distribution of omega 6 essenti al fatty acids in mouse liver lipid fractions.