Effects of flow rate and insulin on triacylglycerol secretion by perfused rat liver.
In rat livers perfused with undiluted rat blood at perfusion rates of 6, 12, or 18 ml/min, hepatic O2 consumption rose with blood flow. Lipogenesis was unaffected by blood flow in control livers and was enhanced by insulin at 12 and 18 ml/min. Very-low-density lipoprotein triacylglycerol secretion also rose with increased flow and was stimulated by insulin at both 6 and 12 ml/min. When glucose was added to livers perfused at 12 or 18 ml/min, uptake was independent of perfusion rate and was slightly stimulated by insulin. Total lipogenesis and the secretion of newly synthesized fatty acids in very-low-density lipoprotein triacylglycerols were unaffected by insulin at either flow rate. The hormone stimulated triacylglycerol secretion at 18 ml/min but inhibited it at 12 ml/min. It seems that in perfused liver, effects of insulin on lipogenesis and very-low-density lipoprotein secretion may be modified not only by changes in O2 consumption (in this case through alterations in blood flow) but also by the choice of substrate.
D000818:Animals; D001646:Bile / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D007773:Lactates / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000378:metabolism*
D001786:Blood Glucose; D005227:Fatty Acids; D007328:Insulin; D007773:Lactates; D008079:Lipoproteins, VLDL; D008112:Liver Glycogen; D014280:Triglycerides; D005947:Glucose