We have previously shown large variations in biological and transcriptomic responses to an ACTH stimulation test . Indeed, the adrenal response to ACTH is a major source of variability of HPA axis function . The present study aims at describing blood transcriptomic, hormonal, and metabolic responses of pigs to a systemic challenge using lipopolysaccharide (LPS), a major component of the outer membrane in gram-negative bacteria . LPS provokes an acute inflammatory syndrome resulting eventually in all kinds of pathophysiological damages . The objective is to analyze the individual variation of the biological responses in relation to the activity of the HPA axis. This was assessed through the level of cortisol released by LPS (this experiment) and also, in the same animals, through the level of cortisol released after an ACTH stimulation test (in an experiment previously published ).