[Relation between changes in the blood levels of beta-endorphin and various hormones during physical exercise].

Dynamics of beta-endorphin, corticotropin, cortisol, somatotropin, insulin and triiodothyronine content were studied using bicycle ergometer in blood of 22 persons during 2 hrs exercises. After an initial increase the beta-endorphin content was subsequently decreased. At the same time, the decrease in the neuropeptide content was accompanied by repeated elevation within the second hr of the exercise, mainly in persons exhibiting high working capacity, while in other persons the hormone concentration decreased below the initial level at the end of the exercise. These alterations in the content of beta-endorphin correlated distinctly with dynamics of pituitary-adrenocortical hormones variation. In untrained persons the initial increase in beta-endorphin content was especially distinctly related to the elevation in somatotropin and to a decrease in insulin content in blood. Concentration of triiodothyronine in blood was altered independently of the alterations of other hormones.