Changes in rat adrenal catecholamines and proenkephalin metabolism after denervation

Adrenal enkephalin-containing peptides are known to increase 10- to 15-fold in the rat after surgical denervation of the gland. In this report we show that the increase is preceded by a lag of several hours, which is indicative of stimulation of protein synthesis at the transcriptional level. The major species of newly appearing enkephalin-containing peptide appears to be the intact precursor, proenkephalin. Processing of proenkephalin to smaller enkephalin-containing peptides in the denervated glands is slow and limited. The only product that accumulates in the process is a peptide of 3-4 kilodaltons that is derived from the carboxyl terminus of proenkephalin. An interesting observation was the dissociation between the effects of denervation on enkephalin-containing peptides and catecholamines. This is surprising because both are localized in the chromaffin granules of the gland.