Is lysolecithin an in vivo constituent of chromaffin granules?

It was recently claimed that lysolecithin (lysophosphatidylcholine) in chromaffin granules is a post-mortem artefact. We have, therefore, determined catecholamine/lysolecithin ratios in adrenal tissues and isolated chromaffin granules. In rat adrenals and bovine medulla the ratios in both tissues and granules were similar. This indicates that even in rapidly frozen rat adrenal glands, sufficient lysolecithin is present in the total tissue to account for its presence in isolated organelles. Owing to the high cortex/medulla ratios such studies cannot be performed with guinea pig or rabbit adrenals. However, isolated chromaffin granules from guinea pig, in contrast to a previous study, do contain lysolecithin. We conclude that lysolecithin is an in vivo constituent of chromaffin granules of all species so far investigated.