Regulation of juvenile hormone synthesis in the blowfly Lucilia cuprina

• Published in: Physiological entomology Vol. 22; no. 2; pp. 183 - 190
• Main Authors: Sutherland, T D, East, P D
• Format: Journal Article
• Language: English
• Published: 01.06.1997
• Subjects: Calliphoridae; Lucilia cuprina
• ISSN: 0307-6962
• DOI: 10.1111/j.1365-3032.1997.tb01156.x

Juvenile Hormone III bisepoxide synthesis by ring gland complexes from third-instar larvae of the blowfly Lucilia cuprina Weidemann (Diptera, Calliphoridae) was measured using a radiochemical assay in vitro. Hormone synthesis is regulated by three distinct mechanisms during development of the final larval instar up to the time of pupariation. The first type of regulation is detected as a rapid decline in hormone release coinciding with the final phase of commitment to pupariation. The second is a neurally mediated inhibition by the brain that acts at all stages of development in third-instar larvae. A protease-sensitive factor from brains of third-instar larvae causes dose-dependent reversible inhibition of Juvenile Hormone III bisepoxide synthesis. The third regulatory signal is a neural inhibition, observed in brain-ring gland complexes of prepupal stages. The first two levels of regulation appear to act early in the synthetic pathway for Juvenile Hormone (JH), whereas the third acts on the final steps of bisepoxide synthesis.