Lipoprotein lipase activity and chylomicron clearance in rats fed a high fat diet.
The relationships of tissue and plasma lipoprotein lipase (LPL) activities to tissue uptake and plasma clearance of 14C-labeled chylomicron-triglyceride (14C-CM-TG) were studied in female rats fed isoenergetic and isonitrogenous control (12% kJ from fat) or high fat diets (72% kJ from fat) for 8 wk. Animals fed the high-fat diet had higher levels of fasting plasma triglycerides and lower LPL activities in heart, renal adipose tissue and post-heparin plasma. Changes in LPL activities of skeletal muscles varied among muscles with higher values in the soleus and plantaris (32-61%) and no differences in the gastrocnemius. The lower LPL activity in renal adipose tissue was associated with lower uptake of fatty acids from 14C-CM-TG by adipose. Fatty-acid uptake from labeled TG was not associated with tissue LPL activity in other tissues. Clearance of 14C-CM-TG from plasma and the half-lives of 14C-CM-TG were similar in both dietary groups. These data indicate that tissue and plasma LPL activities are not a direct index of uptake of fatty acids by tissues or clearance of chylomicron triglycerides.
Brown
C M
CM
Division of Foods and Nutrition, University of Illinois, Urbana 61801.
Layman
D K
DK
D000818:Animals; D002250:Carbon Radioisotopes; D002914:Chylomicrons / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D014280:Triglycerides / Q000097:blood
D002250:Carbon Radioisotopes; D002914:Chylomicrons; D004041:Dietary Fats; D005227:Fatty Acids; D014280:Triglycerides; D008071:Lipoprotein Lipase