Airaghi L, Catania A, Gramigna C, Manfredi M G, Franceschi M, Zanussi C
1st Medical Clinic, University of Milan, Italy.
Int J Neurosci. 1991 Jan-Feb;56(1-4):73-9. doi: 10.3109/00207459108985406.
The response of plasma beta-endorphin (beta-EP) to dexamethasone suppression was studied in 14 patients with Alzheimer's disease (AD), 14 patients with Parkinson's disease (PD), and 13 age-matched controls in order to evaluate whether an impairment of the opiate system is present in these neurodegenerative disorders. Basal circulating beta-EP was in normal range in all subjects, although the mean concentration was slightly reduced in the patients compared to controls. After 1 mg dexamethasone given at 11:00 p.m. the night before, plasma beta-EP concentration measured at 08:00 a.m. and 04:00 p.m. was not inhibited in AD and PD patients while it was significantly reduced in controls. Circulating ACTH and cortisol were similar in patients and controls and a normal inhibition of plasma cortisol after dexamethasone was observed in 13/14 AD and 12/14 PD patients. The resistance of beta-EP to dexamethasone inhibition is consistent with previous clinical and experimental data indicating a disorder of the opiate system in brain degenerative diseases.
