Prostaglandin E2 (PGE2) is involved in a number of physiologic and pathophysiologic events in many tissues of the body. The biologic effects of PGE2 are mediated through interaction with specific membrane-bound G protein-coupled prostanoid EP receptors. EP3 receptor (or PTGER3) is expressed as multiple transcripts through alternative splicing, with each transcript showing a different tissue-specific distribution. PGE2 may mediate fever generation in response to both endogenous and exogenous pyrogens by acting at the EP3 receptor. EP3-mediated neuronal pathways converge at corticotropin-releasing hormone containing neurons in the paraventricular nucleus of the hypothalamus to induce HPA axis activation during sickness.