Response of the hypothalamic-pituitary-adrenal axis to lumbar puncture induced stress.

To assess lumbar puncture (LP) stress as measured by Hypothalamic-Pituitary-Adrenal axis response, serum cortisols were measured before and after LP in Alzheimer's disease (AD) and healthy elderly individuals. There were no differences in baseline serum cortisol. AD group had significantly higher cortisols at 165 minutes post-LP. Growth curve analysis confirmed these findings and showed significant differences in cortisol levels overall. The AD males had higher cortisols at 105 minutes post-LP, but no other consistent gender differences emerged. The findings are consistent with the relative reduction in HPA negative feedback seen in AD. Overall, LP induces little change in group mean cortisol levels relative to inter-individual variation, indicating that while LP is an interesting model of neuroendocrine challenge, it needs to be tested in larger populations.