The role of JH III and ecdysterone in the regulation of the left colleterial gland activities in Periplaneta americana during the reproductive cycle.

We studied the in vitro effects of JH III and ecdysterone on RNA synthesis and secretory activities of the left colleterial gland (LCG) in mature females of Periplaneta americana during the reproductive cycle. We found that RNA synthesis is a cyclic and highly dynamic process. The major increases in poly(A)- RNA synthesis occurred 8 hr before the peak leucine incorporation into colleterial polypeptides, whereas high poly(A)+ RNA synthesis coincided with high leucine incorporation. Depending on the stage of the cycle JH III exhibited stimulatory or inhibitory effects, or caused no change in RNA synthesis. JH III stimulated RNA synthesis in glands from stages in the reproductive cycle with high endogenous RNA synthesis. The pattern of protein synthesis was not affected by JH III. Ecdysterone lowered RNA synthesis in the LCG and induced secretory activity in LCGs isolated at stages far removed from ovulation. JH III reduced the inhibitory effect of ecdysterone on RNA synthesis and inhibited the ecdysterone-induced secretory activity. The presence of ovarioles isolated at 62 hr of the reproductive cycle (onset of in vivo LCG secretory activity) in the incubation medium inhibited RNA synthesis in 32 hr LCG but induced secretory activity. We suggest that changes in synthetic and secretory activities are coordinated with ovulation and ootheca formation through the interactions between JH III and ovarioles, and ecdysterone may also play a role.