| Abstract: | During starvation for 72 h, tumour-bearing rats showed accelerated ketonaemia and marked ketonuria. Total blood ketone bodies] were 8.53 mM and 3.34 mM in tumour-bearing and control (non-tumour-bearing) rats respectively (P less than 0.001). The 3-hydroxybutyrate]/acetoacetate] ratio was 1.3 in the tumour-bearing rats, compared with 3.2 in the controls at 72 h (P less than 0.001). Blood glucose] and hepatic glycogen] were lower at the start of starvation in tumour-bearing rats, whereas plasma non-esterified fatty acids] were not increased above those in the control rats during starvation. After functional hepatectomy, blood acetoacetate], but not 3-hydroxybutyrate], decreased rapidly in tumour-bearing rats, whereas both ketone bodies decreased, and at a slower rate, in the control rats. Blood glucose] decreased more rapidly in the hepatectomized control rats. Hepatocytes prepared from 72 h-starved tumour-bearing and control rats showed similar rates of ketogenesis from palmitate, and the distribution of 1-14C] palmitate between oxidation (ketone bodies and CO2) and esterification was also unaffected by tumour-bearing, as was the rate of gluconeogenesis from lactate. The carcinoma itself showed rapid rates of glycolysis and a poor ability to metabolize ketone bodies in vitro. The results are consistent with the peripheral, normal, tissues in tumour-bearing rats having increased ketone-body and decreased glucose metabolic turnover rates. |
