ArticleSuda T, Liotta AS, Krieger DT.
Science. 1978 Oct 13;202(4364):221-3.
beta-Endorphin is not detectable in plasma from normal human subjects when measured under baseline conditions or after the subjects have received vasopressin, an agent that elevates beta-lipotropin and adrenocorticotropic hormone (ACTH). Significant amounts of beta-endorphin are present in plasma of patients with endocrine disorders associated with increased ACTH and beta-lipotropin production. Highly purified, natural beta-lipotropin is not peripherally converted to beta-endorphin in vivo in normal subjects.