239 Hypoxic preconditioning (PC) provides an effective medication-free tool to increase brain resistance to hypoxia/ischemia. PC is widely used to induce hypoxic/ischemic brain tolerance [3, 4, 9]. Evidence exists that the mechanisms of brain tolerance ensured by the PC are universal, resulting in an increased resistance not only to hypoxia/ischemia, but also to other injurious exposures, including psychoemotional stresses . PC obviously activates basic mechanisms of adaptation, in which the pituitary–adrenal axis (PAA) plays a key role. The PAA is the major endocrine system component and a vital regulator of homeostasis in vertebrates. In addition, in response to real or apparent danger, including extreme factors and stresses, it mobilizes the adaptive resources of the body that are necessary for successful adaptation . An impairment of the PAA and its feedback inhibition induced by injurious exposures leads to the development of maladaptive pathological states . In spite of the well-known key role of the PAA in adaptive mechanisms, direct evidence for the PAA involvement in the injury produced by hypoxia/ischemia and the formation of brain hypoxic tolerance by using of PC is still missing.