AJP - Cell Physiology, Vol 259, Issue 1 C161-C168, Copyright © 1990 by American Physiological Society
Synthesis of chromogranin A, dopamine beta-hydroxylase, and chromaffin vesicles
J. J. Corcoran and N. Kirshner
Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710.
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.
