title: Secretion of [Met]enkephalyl-Arg6-Phe7-related peptides and catecholamines from bovine adrenal chromaffin cells: modification by changes in cyclic AMP and by treatment with reserpine.
abstract: Investigations into the effects of culturing bovine adrenal chromaffin cells in the presence (72 h) of dibutyryl cyclic AMP, forskolin, and reserpine on the level and release of [Met]enkephalyl-Arg6-Phe7 immunoreactivity, noradrenaline, and adrenaline are reported. The assay for [Met]enkephalyl-Arg6-Phe7 immunoreactivity recognises both peptide B, the 31-amino acid carboxy-terminal segment of proenkephalin, and its heptapeptide fragment, [Met]enkephalyl-Arg6-Phe7. Treatments that elevate cyclic AMP increase the amount of peptide immunoreactivity in these cells; this is predominantly peptide B-like immunoreactivity in both control cells and cyclic AMP-elevated cells. Treatment with reserpine gives no change in total immunoreactivity levels, but does not result in increased accumulation of the heptapeptide [Met]enkephalyl-Arg6-Phe7 at the expense of immunoreactivity that elutes with its immediate precursor, peptide B. Cyclic AMP treatment causes either no change or a decrease in levels of accumulated noradrenaline and adrenaline. However, the release of [Met]enkephalin-Arg6-Phe7 immunoreactivity, noradrenaline, and adrenaline is increased by 72-h pretreatment with forskolin or dibutyryl cyclic AMP, whether release is stimulated by nicotine or elevated potassium. In each case the molecular form of [Met]enkephalyl-Arg6-Phe7 immunoreactivity that is released approximately reflects the cell content. Pretreatment with reserpine has no effect on the total [Met]enkephalyl-Arg6-Phe7 immunoreactivity released, but does result in an increased release of the heptapeptide and a decrease in release of peptide B-like immunoreactivity. The studies suggest that the levels of [Met]enkephalyl-Arg6-Phe7 and peptide B available for release are controlled both at the level of proenkephalin synthesis and at the level of double-basic residue proteolysis.
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D002850:Chromatography, Gel; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism*; D009538:Nicotine / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology*
chemical_list: D005576:Colforsin; D004744:Enkephalin, Methionine; D003994:Bucladesine; D009538:Nicotine; C027511:enkephalin-Met, Arg(6)-Phe(7)-; D012110:Reserpine; D000242:Cyclic AMP; D011188:Potassium; D009638:Norepinephrine; D004837:Epinephrine