Revista Ciencias de la Salud (Jun 2006)
Effect of Stress Caused by Academic Tests on Cortisol and ProlactineLevels in a Group of Medical Students
Abstract
Introduction: The relationship betweenimmunological system and stress has been debatedin the last years. Neurohormonal changes produceimmunologic response variations with majorchanges in the cytokines levels, causing depressionof the cytolytic responses due to a decrease in theNK (Natural Killer) cells population (1).Academic stress is a useful stress model to studyhormonal changes in the Hypotalamic-Pituitary–Adrenocortical (HPA) axis (2, 3).Materials and Methods: The present studyevaluates th0e behavior of cortisol and prolactinehormones and their effect on the adaptativeresponses of Herpes Simplex Virus type I in apopulation of 26 medical students with agesbetween 14 and 27 years. Male students represented80.8% of the evaluated population. This is a threestage longitudinal intervention study whereantibodies, cortisol and prolactin levels weremeasured against Herpes Simplex Virus type I.The first measure was done 15 days previous tothe stressful event, the second during the stressfulevent (mid-academic period exams) and the lastone, 15 days posterior to the stressful event. Allsamples were taken from 8:00 am to 10:00 am.Results and Discussion: Prolactine averagevalues were found to be significantly different (p< 0.001) when comparing the three stages.Cortisol values changes were near showingsignificant differences (p = 0.098), with an increaseduring the stressful event and a decrease after theexposure. Antibodies levels of Herpes SimplexVirus type I showed a significant difference (p =0.043) increasing tendency in the three stages.Adaptative responses to Herpes Simplex Virustype I augmented as a result of prolactineconcentration increase due to a stressor eventexposure. This explains an increment in thecytotoxic cell activity (NK cells) which incrementcytokine concentration, such as INF-α, whichamplify humoral IgG antibody mediated response,according with obtained results. Even thoughcortisol levels do not significantly increased duringthe stressful event exposure, they could be enoughto maintain basal prolactine levels without anadaptative response. It can be inferred that cortisolregulates the prolactine synthesis. Results showthat when cortisol concentration decreases,prolactine levels significantly increase.
