1. Administration of tumour necrosis factor (cachectin) and of interleukin-1-α increased the plasma level of non-esterified fatty acids in fed rats, and in the case of interleukin-1-α the blood glycerol level was also increased, suggesting stimulation of adipose tissue lipolysis. There were parallel increases in the plasma level of triacylglycerols. Neither cytokine had significant effects on blood or liver total ketone body (acetoacetate plus 3-hydroxybutyrate) concentrations.
2. In starved rats, the higher plasma non-esterified fatty acid concentration was not increased further by the cytokines. The plasma triacylglycerol level was increased, although the absolute change was less than in fed rats. The ketonaemia associated with starvation tended to be increased by the cytokines, but this was only significant in the case of interleukin-1-α. Parallel changes occurred in hepatic ketone bodies.
3. It is concluded that tumour necrosis factor-α and interleukin-1-α are not responsible for the hypoketonaemia associated with sepsis or other inflammatory states.