The influence of hemolymph-binding protein on juvenile hormone stability and distribution in Manduca sexta fat body and imaginal discs in vitro

Bruce Hammock, Joachim Nowock, Walter Gooddman, Vassiliki Stamoudis, Lawrence I. Gilbert

Research output: Contribution to journalArticle

96 Scopus citations


The wing discs and fat body of Manduca sexta larvae contain enzymes (i.e. carboxylesterase and epoxide hydratase) that can convert the C18 juvenile hormone (JH) to the acid, diol and acid diol. No evidence of oxidative degradation was noted. In vitro studies suggest that JH can be compartmentalized within the cells of the fat body where it is less accessible to degradative mechanisms. Experiments utilizing a hemolymph-binding protein fraction (BPF) in vitro with fat body and imaginal discs indicate that the BPF retards the uptake of JH by tissues and its subsequent degradation by tissue enzymes. BPF also appears to protect JH from degradation by enzymes released into the medium. By these mechanisms the insect can maintain elevated JH titers for relatively long periods. Binding protein may also keep JH in solution in the hemolymph allowing its rapid distribution throughout the insect. The data suggest that the binding protein plays a key role in maintaining juvenile hormone titers.

Original languageEnglish (US)
Pages (from-to)167-184
Number of pages18
JournalMolecular and Cellular Endocrinology
Issue number3
StatePublished - 1975
Externally publishedYes



  • binding proteins
  • carboxylesterase
  • epoxide hydratase
  • insect hormone
  • juvenile hormone metabolism

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

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