title: Circulating beta-endorphin levels at various stages of life: possible connections with migraine pathogenesis.
abstract: Recently, the existence of a circulating peptide, beta-endorphin (B-EP) with potent analgesic properties has been revealed. Our group has evaluated B-EP plasma levels in several physiological and pathological models. The life span pattern of this newly identified hormone was characterized by a progressive increase during prepuberal development, by stable levels in adults with typical circadian and monthly variations, and by a decrease in aging subjects. Cerebrospinal fluid B-EP contents inversely showed a declining linear trend throughout life, which suggests an independent source of B-EP in this compartment. The concomitant changes in the reproductive system suggested the possible influence of gonads on B-EP plasma levels, as confirmed by decreasing B-EP levels in gonadectomized humans and rats. Headache, which is likely to occur concomitantly with hormonal milieu variations, appeared to be associated with a deficiency in the B-EP system, centrally and peripherally, the lowest values being found in the protracted forms of headache.
mesh_terms: D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000375:Aging; D002648:Child; D002675:Child, Preschool; D004723:Endorphins / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008598:Menstruation; D008875:Middle Aged; D008881:Migraine Disorders / Q000097:blood / Q000209:etiology*; D011247:Pregnancy; D011627:Puberty; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone