Abstract
Injection of cyclic AMP, dibutyryl cyclic AMP, cyclic GMP or dibutyryl cyclic GMP into isolated abdomens prepared from 5th instar armyworm larvae, Leucania separata, coused darkening in body color. Injection of melanization and reddish coloration hormone (MRCH) plus theophylline caused more intense melanizatin in isolated abdomen than did injection of MRCH. Injection of dopamine failed to cause melanization in cutucle. These findings imply that cyclic AMP may play a role as an intercellular messenger of MRCH.
