Vicentino C, Constantin J, Bracht A, Yamamoto NS. Long-chain fatty acid uptake and oxidation in the perfused liver of Walker-256 tumour-bearing rats.
LIVER 2002;
22:341-9. [PMID:
12296968 DOI:
10.1034/j.1600-0676.2002.01656.x]
[Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIMS/BACKGROUND
The effect of the Walker-256 tumour on uptake and oxidation of long-chain fatty acids was investigated in perfused livers of rats.
METHODS
Isolated livers were perfused in a non-recirculating system. Fatty acid uptake, ketogenesis, oxygen uptake and 14CO2-production were measured as well as the activities of the acyl carnitine transferases I and II (CAT I and CAT II).
RESULTS
Basal oxygen uptake of livers from tumour-bearing rats was lower. Ketone bodies production derived from the long-chain fatty acids in livers from starved tumour-bearing rats was lower relative to the controls, but 14CO2 production was similar in both groups. The oxygen uptake increment and the mitochondrial NADH/NAD+ redox ratio were also decreased in tumour-bearing rats. The extent of these differences was dependent on the chain length and structure of the fatty acid, the following decreasing sequence of differences between control and tumour-bearing animals being valid: palmitate > oleate > stearate. The CAT I activity of the enzyme isolated from livers of tumour-bearing rats was half that from normal rats when palmitoyl-CoA and oleoyl-CoA were the substrates.
CONCLUSIONS
Ketogenesis from exogenous fatty acids is decreased in the livers of Walker-256 tumour-bearing rats in consequence of the diminished activity of the mitochondrial CAT I. The lower rates of oxygen uptake indicate a decreased ATP synthesis, which is consistent with the in vivo lower phosphorylation potential.
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