Lack of effect on human lipoprotein-triacylglycerol on the function of perfused rat kidney.
We determined whether addition of human lipoprotein-TG to the perfusate for the isolated rat kidney would increase net Na+ reabsorption or maintain renal tissue K+ content. Rat kidneys (n = 6) were perfused for 75 min with a perfusate containing 6 g% of substrate-free albumin in Krebs-Ringer bicarbonate and a mixture of human chylomicrons and very low density lipoproteins (human lipoprotein-triacylglycerol (HL-TG]. Control kidneys (n = 6) were perfused in the substrate-limited state, i.e., without any exogenous substrates added to the perfusate. Means (n = 6) for function of control kidneys were GFR = 808 +/- 50 microliter g-1 X min-1; %T-Na+ = 63.3 +/- 1.3%. A significant loss of tissue K+ occurred: tissue K+ remaining after 75 min of perfusion = 79.1 +/- 1.9%. Although kidney tissue contains lipoprotein lipase, HL-TG (n = 6) did not increase %Na+ reabsorption (64.3 +/- 2.6%) or maintain tissue K+ content (80.6 +/- 2.0%). Therefore, the TG might have been hydrolyzed and taken up for biosynthesis, the rat kidney lipoprotein lipase might have been inactive, or the rat kidney might not use lipoprotein-TG for biosynthesis or oxidation.
D000818:Animals; D001692:Biological Transport; D002914:Chylomicrons / Q000378:metabolism*; D004231:Diuresis; D005919:Glomerular Filtration Rate; D007668:Kidney / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism*; D010477:Perfusion; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
D002914:Chylomicrons; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D012964:Sodium; D011188:Potassium