The effects of phospholipase A2 activating peptides and arachidonic acid upon Ge-evoked secretion from AtT-20 cells

Simon Guild

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

A GTP-binding protein (G-protein), termed G-exocytosis (Ge), mediates the effects of calcium ions in the late stages of the adrenocorticotrophin (ACTH) secretory pathway. An activator of Ge, mastoparan, also stimulates phospholipase A(2) and so a comparison of other phospholipase A(2)-activating peptides, melittin and phospholipase A(2)-activating peptide was made with mastoparan to assess whether phospholipase A(2)activation was an important component of Ge-evoked secretion. All three peptides stimulated ACTH secretion in the effective absence of calcium ions from permeabilised cells, actions potentiated by a phospholipase A(2)inhibitor. Ca2+-evoked secretion from permeabilised cells was similarly potentiated by a phospholipase A, inhibitor. Furthermore, arachidonic acid inhibited Ca2+- and Ge-evoked ACTH secretion, an action blocked by the cyclo-oxygenase inhibitor ibuprofen. This study suggests that the products of phospholipase A(2)-generated arachidonic metabolism may exert an inhibitory action on the late post-Ca2+ stages of the ACTH secretory pathway and that prostaglandins may be the active agents in this capacity. (C) 2001 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)163-171
Number of pages9
JournalEuropean Journal of Pharmacology
Volume424
DOIs
Publication statusPublished - 27 Jul 2001

Keywords

  • G-protein
  • phospholipase A(2)
  • exocytosis
  • ACTH (adrenocorticotrophin)
  • anterior pituitary
  • PITUITARY-TUMOR CELLS
  • RAT ADENOHYPOPHYSIS INVITRO
  • PERMEABILIZED ATT-20 CELLS
  • CHROMAFFIN CELLS
  • ARACHIDONIC-ACID
  • GUANINE-NUCLEOTIDES
  • BETA-ENDORPHIN
  • KINASE-C
  • HUMAN-PLATELETS
  • ACTH-SECRETION

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