Beta-Endorphin is processed differently in specific regions of rat pituitary and brain.

Abstract

Recent studies have shown that β-endorphin is found in the pituitary with two related peptides, the C′-fragment (β-endorphin1-27)1,2 and the des-histidine derivative of the C′-fragment (β-endorphin1-26)3, and that each of these peptides (Fig. 1) occurs also in an α,N-acetyl form3,4.The six peptides are derived from a single precursor by differential proteolytic cleavage and acetylation. The fact that different forms of β-endorphin predominate in different regions of the pituitary5,6 implies that there are region-specific differences in processing of the precursor. Because β-endorphin is known to occur widely in the brain7,8 as well as in the pituitary we have now investigated the distribution of the six peptides in selected regions of rat brain. We report here that, as in the pituitary, different regions of the brain contain strikingly different proportions of the six β-endorphin-related peptides, apparently as a result of differential processing.