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Secretion of [Met]Enkephalyl‐Arg 6 ‐Phe 7 ‐Related Peptides and Catecholamines from Bovine Adrenal Chromaffin Cells: Modification by Changes in Cyclic AMP and by Treatment with Reserpine
Author(s) -
Adams Maria,
Boarder Michael R.
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb03416.x
Subject(s) - forskolin , reserpine , medicine , endocrinology , proenkephalin , peptide , chemistry , prohormone , secretion , neurotensin , catecholamine , neuropeptide , biology , enkephalin , biochemistry , stimulation , hormone , receptor , opioid
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‐Arg 6 ‐Phe 7 immunoreactivity, noradrenaline, and adrenaline are reported. The assay for [Met]enkephalyl‐Arg 6 ‐Phe 7 immunoreactivity recognises both peptide B, the 31‐amino acid carboxy‐terminal segment of proenkephalin, and its heptapeptide fragment, [Met]enkephalyl‐Arg 6 ‐Phe 7 . 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 result in increased accumulation of the heptapeptide [Met]enkephalyl‐Arg 6 ‐Phe 7 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 noradrena‐line and adrenaline. However, the release of [Met]enkephalin‐Arg 6 ‐Phe 7 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‐Arg 6 ‐Phe 7 immunoreactivity that is released approximately reflects the cell content. Pretreatment with reserpine has no effect on the total [Met]enkephalyl‐Arg 6 ‐Phe 7 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‐Arg 6 ‐Phe 7 and peptide B available for release are controlled both at the level of proenkephalin synthesis and at the level of doublebasic residue proteolysis.