Hepatic denervation impairs the assembly and secretion of VLDL-TAG.
VLDL secretion is a regulated process that depends on the availability of lipids, apoB and MTP. Our aim was to investigate the effect of liver denervation upon the secretion of VLDL and the expression of proteins involved in this process. Denervation was achieved by applying a 85% phenol solution onto the portal tract, while control animals were treated with 9% NaCl. VLDL secretion was evaluated by the Tyloxapol method. The hepatic concentration of TAG and cholesterol, and the plasma concentration of TAG, cholesterol, VLDL-TAG, VLDL-cholesterol and HDL-cholesterol were measured, as well as mRNA expression of proteins involved in the process of VLDL assembly. Hepatic acinar distribution of MTP and apoB was evaluated by immunohistochemistry. Denervation increased plasma concentration of cholesterol (125.3 +/- 10.1 vs. 67.1 +/- 4.9 mg dL(-1)) and VLDL-cholesterol (61.6 +/- 5.6 vs. 29.4 +/- 3.3 mg dL(-1)), but HDL-cholesterol was unchanged (45.5 +/- 6.1 vs. 36.9 +/- 3.9 mg dL(-1)). Secretion of VLDL-TAG (47.5 +/- 23.8 vs. 148.5 +/- 27.4 mg dL h(-1)) and mRNA expression of CPT I and apoB were reduced (p < 0.01) in the denervated animals. MTP and apoB acinar distribution was not altered in the denervated animals, but the intensity of the reaction was reduced in relation to controls.
Molecular Biology of the Cell Group, Institute of Biomedical Sciences, Department of Cell and Developmental Biology, University of São Paulo, Brazil.
Fábio Luís
FL
Tavares
Marília Cerqueira Leite
MC
Seelaender
D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D003714:Denervation; D008079:Lipoproteins, VLDL / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000097:blood / Q000378:metabolism; D008099:Liver / Q000294:innervation* / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000097:blood / Q000378:metabolism
D001055:Apolipoproteins B; D008079:Lipoproteins, VLDL; D014280:Triglycerides; C030106:very low density lipoprotein triglyceride; D002784:Cholesterol