Peripheral plasma levels of beta-endorphin in alcoholics and highly trained athletes and the relationship to a measure of central opioid tone.
Human beta-endorphin-like immunoactivity was measured in highly trained athletes (n = 10), alcoholics in the early phase of abstinence (n=9) and normal controls (n=15) using the Nichols Allegro immunoradiometric assay. The assay was examined for cross reactivity against related peptides, beta-lipotropin and human N-acetyl beta-endorphin. Venous blood sampling was carried out in the morning at 0900 and 1100 hours in a fasting state. Using two-way analysis of variance there was a significant effect of subject group on beta-endorphin concentration (p=0.029). Post-hoc analysis using the Bonferroni t-test showed that the source of the difference was the alcoholic group having significantly lower beta-endorphin immunoreactivity (p < 0.05). There was no difference between the controls and the athletes. There was a positive correlation between plasma beta-endorphin level at 1100 hours and the subsequent ACTH incremental response to naloxone in the group as a whole (r=0.48, p=0.004). The assay showed 100% cross reactivity with beta-lipotropin and 73% cross reactivity with N-acetyl-beta-endorphin. We conclude that alcoholics have reduced levels of beta-endorphin-like immunoactivity. While beta-endorphin is known not to cross the blood-brain barrier, levels of plasma beta-endorphin-like immunoactivity may indirectly reflect central opioid activity.
Department of Endocrinology, Christchurch Hospital, New Zealand.
W J
WJ
Inder
J H
JH
Livesey
R A
RA
Donald
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000437:Alcoholism / Q000097:blood*; D015992:Body Mass Index; D005215:Fasting; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay; D008297:Male; D009270:Naloxone; D009292:Narcotic Antagonists; D012680:Sensitivity and Specificity; D013177:Sports; D001615:beta-Endorphin / Q000097:blood*; D008083:beta-Lipotropin / Q000097:blood
D009292:Narcotic Antagonists; D009270:Naloxone; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D008083:beta-Lipotropin