Synthesis of chromogranin A, dopamine beta-hydroxylase, and chromaffin vesicles.
Primary cultures of bovine adrenal medullary cells synthesize chromogranin A (CgA) and dopamine beta-hydroxylase (DBH) and incorporate them into chromaffin vesicles. The incorporation of L-[35S]methionine into CgA, DBH, and total protein was approximately linear for 8 h at methionine concentrations of 12.5, 25, and 50 microM. Newly synthesized CgA and DBH were initially incorporated into vesicles of low buoyant density that matured over 24 h into vesicles having the greater buoyant density of chromaffin vesicles. Approximately 10% of the newly synthesized CgA is released constitutively within 4 h of formation, approximately 30-40% appears to be degraded, and the remainder is incorporated into chromaffin vesicles, which can secrete CgA in response to nicotinic stimulation. Newly synthesized DBH follows a similar course. Once incorporated into chromaffin vesicles, the newly synthesized CgA and DBH appear to be stable for 2-3 days and then decline with a half-time of 3-4 days. Primary cultures of bovine adrenal medullary cells are a good model system for studying factors regulating CgA and DBH synthesis and the formation of chromaffin vesicles.
Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710.
J J
JJ
Corcoran
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N
Kirshner
D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D053379:Chromogranin A; D002864:Chromogranins / Q000096:biosynthesis* / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000096:biosynthesis* / Q000378:metabolism; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D011865:Radioisotope Dilution Technique; D013462:Sulfur Radioisotopes
D053379:Chromogranin A; D002864:Chromogranins; D009419:Nerve Tissue Proteins; D013462:Sulfur Radioisotopes; D008715:Methionine; D004299:Dopamine beta-Hydroxylase