Apparent inhibition of hepatic triacylglycerol secretion, independent of synthesis, in high-fat fish oil-fed rats: role for insulin.
Rats were fed Chow (C; low-fat control) or a purified high-fat (30% of calories) low cholesterol diet containing menhaden oil (MO), corn oil (CO) or lard (L) for 2, 4 or 6 weeks. Rats were killed after an overnight fast. MO-fed rats had a larger weight/body weight that was accompanied by a lower mg liver DNA/g liver but unchanged liver DNA/body weight, indicating that hepatomegaly in the MO-fed rats was due to cellular hypertrophy. MO-feeding prevented the rise in plasma triacylglycerol and cholesterol observed with the other high-fat diets. There was a marked progressive accumulation of total liver triacylglycerol in the MO- and CO-fed rats. Plasma insulin was reduced in the MO-fed rats relative to all other groups. There were strong positive relationships between plasma insulin and triacylglycerol and between insulin and cholesterol in the high-fat-fed rats. Total liver glucose-6-phosphate dehydrogenase and malic enzyme activities were reduced by MO-feeding and were directly correlated with plasma cholesterol and insulin. These data are consistent with an apparent inhibition of hepatic triacylglycerol secretion by high-fat fish oil-feeding that is independent of the inhibitory effects on triacylglycerol synthesis. These data suggest a role for insulin in regulating the plasma triacylglycerol and cholesterol concentrations in MO-fed rats.
Otto
D A
DA
Department of Research, Baptist Medical Centers, Birmingham, AL 35211.
Tsai
C E
CE
Baltzell
J K
JK
Wooten
J T
JT
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D003314:Corn Oil / Q000008:administration & dosage / Q000494:pharmacology; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007328:Insulin / Q000097:blood; D007657:Ketone Bodies / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D015430:Weight Gain / Q000187:drug effects
D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D005395:Fish Oils; D007328:Insulin; D007657:Ketone Bodies; D014280:Triglycerides; C033266:Menhaden oil; D003314:Corn Oil; D002784:Cholesterol; D008291:Malate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; C029310:lard