β-Endorphin in the human gallbladder

Abstract

The presence of β-endorphin-like immunoreactivity (β-END-LI) in human gallbladder and its release were examined by means of radioimmunochemical measurements and immunohistochemical stainings. β-END-LI was detected in the gallbladder ( 27.2 ± 3.2 ng/g wet weight, mean ± S.E.). The immunoreactivity in β-END-LI extracted from the gallbladder was similar to that of synthetic β-END, judging from the result of its inhibition curve parallel to that of the synthetic substance in the radioimmunoassay (RIA) system. On gel-filtration chromatography of a gallbladder extract, two components of β-END-LI were found; one eluted on a position of β-lipotropin (β-LPH) and another on a position of synthetic β-END. Specific β-END-LI positive cells were detectable in metaplastic mucous glands. When human gallbladder mucosa was perfused with a solution of 10 −8 M or 10 −6 M cholecystokinin octapeptide (CCK-8), the release of β-END-LI from mucosa into the perfusate increased 2–3 fold. These results indicate that β-END-LI present in human gallbladder is released by the direct action of CCK-8 on the gallbladder mucosa and suggest that it may have a physiological or pathophysiological role.