Resistance of beta-endorphin to dexamethasone inhibition in Parkinson's and Alzheimer's diseases.
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.
Airaghi
L
L
1st Medical Clinic, University of Milan, Italy.
Catania
A
A
Gramigna
C
C
Manfredi
M G
MG
Franceschi
M
M
Zanussi
C
C
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000368:Aged; D000544:Alzheimer Disease / Q000097:blood*; D003907:Dexamethasone / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010300:Parkinson Disease / Q000097:blood*; D001615:beta-Endorphin / Q000097:blood*
D001615:beta-Endorphin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone