Observations on the localization of labelled amino acid in mouse adrenal chromaffin cells after the injection of L-[4,5-3H] leucine.

The intracellular localization of L-[4,5-3H] leucine in chromaffin cells has been observed using light and electron microscopic autoradiography and the association of the labelled amino acid with particular cell components confirmed by statistical analysis. By making observations at short intervals after a single intravenous pulse of [3H]leucine it has been possible to follow the movement of the isotope from the endoplasmic reticulum through the Golgi complex to the chromaffin granules. No evidence for movement of the label through the Golgi complex was observed in adjacent cortical cells. The time sequence of transport of the amino acid through the various cell organelles was very similar to that observed by previous workers in protein-secreting exocrine cells.