Discovery and Partial Characterization of Prothoracicotropic Hormones of the Gypsy Moth, Lymantria Dispar

The brain neuropeptide prothoracicotropic hormone (PTTH) is an ecdysiotropin that drives post-embryonic growth and development through the stimulation of ecdysteroid production by the prothoracic glands (PG) (Gilbert et al., 1980). Research to isolate PTTH has utilized primarily two species, Bombyx mori (Ishizaki and Suzuki, 1984) and Manduca sexta (Bollenbacher and Granger, 1985). Characterization and isolation studies have used both in vivo (Bombyx, Ishizaki et al, 1983, Nagasawa et al, 1984a; Manduca, Kingan, 1981) and in vitro (Bombyx, Nagasawa et al, 1984a; Okuda et al, 1985; Manduca, Bollenbacher et al, 1979) bioassays. Recent work on Bombyx and Manduca PTTH demonstrates that biological activity is associated with two molecular-weight ranges of ca. 20–28 kD and ca. 4–7 kD (Ishizaki et al., 1983, Bollenbacher et al., 1984). A family of 4 kD PTTH’s has been isolated from Bombyx (Nagasawa et al., 1984b).