N-Acetylated endorphins in ovine anterior pituitary and neuro-intermediate lobe

M. C. Cheng, A. I. Smith, J. A. Clements, J. W. Funder

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We have used an antiserum for immunohistochemistry and RIA/RP-HPLC which recognizes all fragments of N-acetylated endorphin (NacEP). In the rat neurointermediate lobe (N-IL), in addition to the N-acetylated forms of immunoreactive-β-endorphin (ir-βEP) already reported, we have demonstrated NacβEP1-17 as a minor component. In the sheep pituitary processing of βEP is markedly different. In the anterior pituitary (AP), staining was indistinguishable with βEP and NacEP antisera, in contrast with the rat where many fewer AP cells stained with the NacEP antiserum. Secondly, as in the rat, all N-IL cells stained with both antisera; on RP-HPLC, however, the major forms of NacEP in the sheep N-IL were NacβEP1-17 (∼40%), NacβEP1-27 (∼25%) and NacβEP1-16 (∼20%), with NacβEP1-31 (∼2%) as a minor component. A similar profile was seen on RP-HPLC of sheep AP. These data suggest that (1) patterns of processing in sheep AP are similar to those in N-IL, though the extent of acetylation is less and (2) in the sheep pituitary low molecular weight acetylated fragments predominate, in contrast with the rat.

Original languageEnglish
Pages (from-to)1045-1050
Number of pages6
Issue number6
Publication statusPublished - 1 Jan 1987
Externally publishedYes


  • Anterior pituitary
  • N-Acetylation
  • Neuro-intermediate lobe
  • Sheep
  • β-Endorphin

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