AMOUNT AND TYPE OF DIETARY-FAT REGULATE PANCREATIC LIPASE GENE-EXPRESSION IN RATS

Both amount and type of dietary triglycerides regulate pancreatic lipa se, but the mechanism is not fully understood. This study investigated the effects of type (safflower oil and lard) and amount [low (50 g/kg diet) or moderate (174 g/kg diet)] of fat on rat pancreatic lipase (r PL) activity and mRNA levels. Polyunsaturated safflower oil resulted i n 80% greater lipase activity compared with the saturated lard at mode rate levels, whereas safflower oil resulted in 50% lower lipase activi ty compared with lard at low levels. The rPL-3 mRNA levels were greate r in rats fed the moderate safflower oil diet (163%) or the moderate l ard diet (212%) than in those fed the respective low fat diets and wer e 45% greater in those fed safflower oil than in those fed lard. The r PL-1 mRNA levels were greater in rats fed moderate safflower oil (50%) or lard (135%) than in those fed the respective low fat diet, but the se levels were not affected by type of fat, in contrast to rPL-3 mRNA levels. The amount of fat independent of its type regulates pancreatic lipase pre-translationally, because increasing dietary saturated or p olyunsaturated fat resulted in parallel changes in rPL-3 and rPL-1 mRN A levels. However, type of fat may regulate pancreatic lipase at other levels such as translational or post-translational, because the 212% increase in rPL-3 mRNA in rats fed the moderate lard diet compared wit h the low lard diet did not result in greater pancreatic lipase activi ty.