Synthesis of enkephalins by guinea-pig striatum in vitro.

A method for obtaining incorporation of labelled amino acids into enkephalins of guinea-pig striatum in vitro and isolating the labelled enkephalins is described. The incorporation of [3H]tyrosine increases with time after a delay of 2 h. Cycloheximide added during this time, but not at later stages, inhibits incorporation. The results indicate that the enkephalins are produced locally, probably by ribosomal synthesis. The lag period may be due to the time required for the synthesis of precursors and their conversion to the enkephalins.