The in vitro release of prothoracicotropic hormone (PTTH) from the brain—corpus cardiacum—corpus allatum complex of silkworm, Bombyx mori

Abstract An in vitro system for evaluation of the exact PTTH release from the brain-CC-CA complex of Bombyx mori was developed. The PTTH release induced with a high potassium ion concentration reached the maximal level in 30 min and was dependent on the concentration of the potassium ion. The PTTH release was also dependent on the calcium ion and was induced with a calcium ionophore, indicating that increasing intracellular calcium ion might be essential for its release. Carbachol (acetylcholine agonist) induced the PTTH release fastest, followed by dopamine and serotonin in that order, while norepinephrine exerted no effect. Carbachol might act in the brain of brain-CC-CA complex.