Fig. 9.
Effect of high-fat diets on hepatic elongase and desaturase expression. Male C57BL/6 mice were fed lard diets [10% calories (low fat) or 60% calories (high fat) as lard] for 10 weeks as described in Materials and Methods (48). A: After 9 weeks on the low- and high-fat diets, mice were assessed for glucose tolerance (see Materials and Methods). Blood glucose was measured at the times indicated. Results are expressed as blood glucose (mg/dl) (means ± SD; n = 8 in each group). B: Effect of dietary fat on SREBP (microsomal and nuclear), ChREBP, MLX, and HNF-4α. After 10 weeks on the diet, livers were recovered for nuclear and microsomal protein and RNA extraction as described for Fig. 8. Nuclear and microsomal proteins were measured as described in Materials and Methods. Representative immunoblots from duplicate samples for each treatment are shown. The effect of dietary fat on the abundance of these proteins was quantified and expressed as fold change (means; n = 4 animals/group) induced by the high-fat diet. Statistical significance (P) was assessed by Student’s t-test. C: Effect of dietary fat on elongase and desaturase expression. RNA was extracted and used for qRT-PCR analysis of elongase and desaturase expression. Results are expressed as fold change (transcript/cyclophilin) (means ± SD; n = 8). * P ≤ 0.05. D: Effect of dietary fat on elongase activity. Hepatic microsomal preparations were used for fatty acid elongase assays (see Materials and Methods). Results are expressed as elongase activity (nmol [14C]malonyl-CoA assimilated into fatty acids/mg protein) (means ± SD; n = 8). * P ≤ 0.05 versus 10% calories as fat by Student’s t-test.