EFFECT OF CULTURE-MEDIUM ON THE IN-VITRO SECRETION ACTIVITY OF PROTHORACIC GLANDS FROM PSEUDALETIA-SEPARATA

The prothoracic glands (PGs) taken from the last instar of the common armyworm, Pseudaletia separata, were cultured in various media for the purpose of finding a suitable medium for relatively long-term culture of PGs. Among the tested culture media, MGM-450 medium without serum was the best to maintain PG: cells viable for relatively long periods, and to continue to secrete ecdysteroids. Secretion of ecdysteroid by the PG in vitro became marked when the PG was taken from last instar l arvae older than 2 days after the last molt. PGs cultured in any of th e media secreted ecdysteroid only within the first 2 h after placing t hem in culture, however, in the MGM-450 medium, the PGs secreted ecdys teroid even after 5 days of culture. Arch. Insect Biochem. Physiol. 38 :147-154, 1998. (C) 1998 Wiley-Liss, Inc.