Life exists through the maintenance of a complex dynamic equilibrium, termed homeostasis, that is constantly challenged by internal or external adverse forces, termed stressors, with can be emotional or physical in nature. Thus, stress is defined as a state of threatened or perceived by the individual as threatened homeostasis and it is re-established by a complex repertoire of behavioural and physiologic adaptive responses of the organism. Neuroendocrinic hormones have a crucial role in coordinating basic as well as threatened homeostasis; also, they intervene in pathogenesis of dyshomeostatic or cacostatic situations of disease.