Figure 6. Effects of rapamycin and nutrients on ecdysone levels and 4E-BP phosphorylation states, respectively.

(A) Effects of rapamycin treatment on ecdysone levels. Prothoracic glands and hemolymph from larvae fed 0.1 mg/ml rapamycin- or control DMSO-treated diets were isolated at average weights of 0.59±0.04 g and 0.61±0.02 g, respectively (Student’s t-test, p = 0.70, n = 8 larvae per group). Significant differences were observed between control and rapamyin-fed groups in hemolymph ecdysteroid levels, and in ecdysone secretion by isolated prothoracic glands (Student’s t-test, p = 0.014 and 0.009, respectively). Error bars indicate standard error for ecdysone secretion. (B) Effect of nutrients on 4E-BP phosphorylation states in the prothoracic glands and the fat body. In both the prothoracic glands and the fat body, the presence of amino acids led to elevated phosphorylated 4E-BP levels relative to sucrose fed larvae or starved larvae. In the prothoracic glands, phospho-4E-BP levels were also elevated in the starved larva relative to the sucrose fed larva.