The possible role of beta-endorphin in pathogenesis of obesity and essential hypertension

In order to evaluate the role of beta-endorphin in the pathogenesis of obesity and essential hypertension 44 subjects were investigated: 12 nonobese hypertensives, 11 obese hypertensives, 11 obese normotensives and 10 normal subjects. Plasma concentrations of beta-endorphin and cortisol were measured by radioimmunological and ACTH by immunoradiometric methods. The plasma concentrations and the circadian rhythms of ACTH and cortisol secretion were normal in all groups investigated. A circadian rhythm of beta-endorphin secretion was demonstrated in nonobese hypertensives and in normal subjects. The plasma concentrations of beta-endorphin were twice higher than those in nonobese subjects. Also, in all obese patients the circadian rhythm of beta-endorphin secretion was blunted. The increased concentrations and the altered circadian rhythm of beta-endorphin in all obese subjects may point to a role of beta-endorphin in the pathogenesis of obesity rather than in that of essential hypertension.