Bovine adrenal medulla: Synthesis and secretion of radioactively labelled catecholamines and chromogranins

OBSERVATIONS ON THE LOCALIZATION OF LABELLED AMINO ACID IN MOUSE ADRENAL CHROMAFFIN CELLS AFTER THE INJECTION OF l-[4,5-3H]LEUCINE

“…Further evidence for the specific labelling of granules containing recently synthesized chromogranin also comes from the work of Baumgartner, Gibb, Hörtnagl, Snider & Winkler (1974) using [35S]sulphate as the label. The present findings indicating a labelling of the Golgi zone and of the Golgi dense granules between 15 min and 4 h after pulse labelling in vivo suggest that the latter are the recently synthesized chromaffin granules identified biochemically by Winkler et al (1971Winkler et al ( , 1972. It should be noted that proper identification of recently synthesized granules depends upon statistical analysis of appropriate population samples and not on the apparent localization of a silver grain over an individual cytoplasmic organelle, since even at the electron micro¬ scopic level the resolution of autoradiography is too low to make simple evaluation of results valid.…”

“…The present results are of interest in relation to the observations of Winkler, Hörtnagl, Schöpf, Hörtnagl & zur Nedden (1971) and Winkler, Schöpf, Hörtnagl & Hörtnagl (1972) on the localization of [3H]leucine in the perfused bovine adrenal gland. Winkler et al (1971) noted a gradual increase in the relative specific activity of the soluble protein of the large granule fraction of homogenized adrenal medulla up to 4 h after labelling and in 1972 they identified the label in the soluble chromogranin of a distinct large granular particle that had a lower density than mature granules.…”