The purpose of this study is to investigate the possible ways in which the neurohormonal mediator molecule oxytocin may modulate the response to stress in normal healthy adult males exposed to a variety of different type of stressors. The knowledge gained from the study will be of use in enhancing the understanding of the neurohormonal mechanisms by which human beings midulate their physiological responses to differing types of stress, specifically in understanding the possible neurohoromonal mediator.