Fig. 2. JH causes re-expression of BR mRNA in Manduca pupal wings in vitro. Eighteen-hour-old pupal wings were precultured for 24 hours in either hormone-free medium (no hormone or 20E) or 1 µg/ml (3x10^–6 M) JH I (for those being exposed to JH). At time 0 they were transferred to medium without hormone or with 1 µg/ml JH I, 5 µg/ml (10^–5 M) 20E, or both, and cultured for various times, then the RNA extracted and analyzed as in Fig. 1.