ECDYSTEROID SYNTHESIS IN DISSOCIATED CELLS OF THE PROTHORACIC GLAND OF THE SILKWORM, BOMBYX-MORI

A method for the preparation of viable cells of prothoracic glands of Bombyx mori was developed. Dissected prothoracic glands (PGs) from lar vae at the spinning stage were incubated in the Grace's insect culture medium containing dispase (6,000 PU/ml of medium at pH 6.5) at 37 deg rees C for 15 min. After centrifugation for 2 min at 250 rpm, resultan t cells were incubated with Grace's insect medium for designated times . After this treatment 87+/-7% of the cells remained viable as judged by exclusion of trypan blue. The amounts of ecdysteroid secreted into medium by these cells were approximately 70 to 80% of the amounts secr eted by intact PGs. The rates of ecdysteroid secretion over 6 hr in or gan culture and in cell culture were quite similar, although the amoun ts of ecdysteroid detected in the latter medium were somewhat lower.