Bombyx Prothoracicotropic Hormone

Prothoracicotropic hormone (Bombyx PTTH) of the silkworm, Bombyx mori, was extracted from adult heads. Bombyx PTTH is suggested to be a glycopeptide and consists of two essentially identical subunits. Amino acid sequencing and cDNA analysis revealed the whole amino acid sequence of the subunit, composed of 104-109 residues. Bombyx PTTH stimulated adult development in brainless Bombyx pupae at a dose of ca. 0.1 ng and also enhanced the release of ecdysone in vitro at a concentration of 10-11 M. Immunohistochemistry and in situ hybridization showed that Bombyx PTTH was transcribed and translated in two pairs of dorso-lateral neurosecretory cells in the brain.