Gamma gamma (gamma gamma) enolase amount and enolase isozyme activities were measured in brain structures involved in stress response (hypothalamic paraventricular and supraoptic nuclei, locus coeruleus, hippocampus, A1 and A2 regions, hypophysis). Analyses were made in rats after immobilization or adrenalectomy, two experimental conditions that have been reported to increase brain glucose consumption and protein synthesis. In control rats enolase content was highest in the A1 region and hippocampus and lowest in hypophysis. A positive correlation was found between the enzyme level and its activity in the brain regions studied. However, in stressed or adrenalectomized rats, the level of glycolytic enzyme enolase was not significantly modified.