The induction of interleukin-1 in humans and its metabolic effects

To investigate the metabolic effects of interleukin-1 and its role as a mediator of host responses to trauma and sepsis, we injected seven healthy male subjects with etiocholanolone, an inflammatory agent that stimulates systemic responses thought to be mediated by interleukin-1. The subjects were fed a constant diet during each 4-day study and received three daily intramuscular injections of etiocholanolone, 0.10 mg/kg. Etiocholanolone injection resulted in inflammation, fever, leukocytosis, increased serum C-reactive protein, hypoferremia, and increased plasma activity of interleukin-1/lymphocyte-activating factor. Plasma concentrations of the counterregulatory hormones were normal. Protein metabolism, as reflected in nitrogen balance, 15N turnover, and forearm flux of alanine and glutamine, was unaltered. Serum glucose and insulin levels and tissue responsiveness to insulin were normal. This dissociation of acute-phase and catabolic responses may reflect the magnitude of the stimulus; higher levels of interleukin-1 may initiate catabolic responses. Alternatively, other mediators such as the counterregulatory hormones may direct the catabolic responses that occur after injury and sepsis.