Effect of octopamine on the activity of juvenile-hormone esterase in the silkworm Bombyx mori and the red flour beetle Tribolium freemani

Akinori Hirashima, Eiko Suetsugu, Shiori Hirokado, Eiichi Kuwano, Eiji Taniguchi, Morifusa Eto

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

This study focuses on the effect of octopamine (OA) on metamorphosis of the silkworm Bombyx mori and the red flour beetle Tribolium freemani Hinton. Titers of OA and juvenile-hormone esterase (JHE) were measured at various larval and pupal stadia of both insects. Effects of OA, OA agonists, and antagonists on metamorphosis and JHE activity were also examined. At day 2, peaks of OA and JHE activity were observed in third instars, and at day 3, a sharp peak of OA was observed, followed by a large peak of JHE activity at day 4 in last instars of B. mori. However, no peaks of OA and JHE activity were observed in fourth instars. A high titer of OA appeared at days 2-4, followed by a peak of JHE activity at day 7 and the second OA peak at day 9 after the start of assay of T. freemani. At pupation, a small peak of OA and the highest activity of JHE were observed. The effects of OA on JHE activity were examined in vitro, because the relationship could be responsible for triggering pupation in B. mori and T. freemani larvae. Exogeneous OA (0.1-10 mM) stimulated the JHE activity of final instars (day 2) of B. mori in vitro. Similarly, the presence of OA (10 mM) activated the JHE activity of newly ecdysed T. freemani pupae in vitro. OA antagonists chlorpromazine and gramine delayed the start of spinning and reduced the JHE activity of B. mori, when applied in diet at 10-100 ppm. Some OA agonists stimulated the pupation and JHE activity of T. freemani larvae reared under crowded conditions, when topically applied. Thus, OA may contribute to activation of the events preparatory to a pupal molt, i.e., the secretion of OA increases JHE activity followed by stimulation of pupation.

Original languageEnglish
Pages (from-to)373-381
Number of pages9
JournalGeneral and Comparative Endocrinology
Volume116
Issue number3
DOIs
Publication statusPublished - Dec 1999

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology
  • Endocrinology

Fingerprint Dive into the research topics of 'Effect of octopamine on the activity of juvenile-hormone esterase in the silkworm Bombyx mori and the red flour beetle Tribolium freemani'. Together they form a unique fingerprint.

  • Cite this