ROLE OF BURSICON IN MELANIZATION AND ENDOCUTICLE FORMATION IN ADULT FLESHFLY SARCOPHAGA BULLATA

The rôle of the hormone bursicon in melanization and growth of the cuticle in adults of Sarcophaga bullata has been investigated. Bursicon induces melanization of the outer layers of the cuticle and deposition of postemergent endocuticle. Endocuticle formation is inhibited by actinomycin D and puromycin with no discernible effect on melanization, and melanization is selectively inhibited by a dopa-decarboxylase inhibitor suggesting that this enzyme is involved in melanization but is not induced de novo by bursicon. These results indicate that RNA and protein synthesis are required for the bursicon-induced formation of endocuticle. In apparent contradiction to the latter suggestion, bursicon had no measurable effect on the incorporation of uridine-3H into the epidermis; it did, however, affect the incorporation of leucine-3H into the epidermis, causing an enhanced uptake. © 1969.