An insect brain peptide as a member of insulin family.

Amino acid sequencing of bombyxin (previously called 4K-PTTH) isolated from the heads of the silkmoth Bombyx mori has disclosed sequence homology of this insect neuropeptide with insulin. Immunohistochemistry using an antibody against a synthetic bombyxin fragment detected 4 pairs of immunoreactive neurosecretory cells in the dorso-medial region of the Bombyx brain. The same cells were reactive to bovine insulin antibody.