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A putative new juvenile peptide hormone in lepidopteran insects
1Biochemical Laboratory, Hokkaido University, Sapporo, Japan.
Biochemical and Biophysical Research Communications
|June 30, 1992
Summary
A novel growth-blocking peptide (GBP) was found in armyworm larvae before the final molt, suggesting a new role in regulating juvenile characteristics alongside juvenile hormone (JH). This peptide is naturally present, not just induced by parasitoids.
Area of Science:
- Insect endocrinology
- Peptide hormone research
- Lepidopteran physiology
Background:
- Growth-blocking peptide (GBP) with juvenile hormone (JH) esterase repressive activity was previously isolated from parasitized armyworm larvae.
- The role and natural occurrence of GBP in insect development were not fully understood.
Purpose of the Study:
- To investigate the presence and distribution of GBP in both parasitized and unparasitized armyworm larvae.
- To determine if GBP occurs naturally in larvae before the final instar.
Main Methods:
- Analysis of larval plasma from parasitized and unparasitized armyworm (Pseudaletia separata) larvae.
- Detection of growth-blocking peptide (GBP) in different larval instars.
Main Results:
- Growth-blocking peptide (GBP) was detected in the plasma of unparasitized penultimate (5th) instar larvae.
- GBP was also found in parasitized last (6th) instar larvae.
- No detectable GBP was found in unparasitized last instar larvae.
Conclusions:
- GBP is naturally present in insect larvae before the final instar, independent of parasitization.
- GBP likely plays a role in regulating juvenile characteristics, potentially coordinating with juvenile hormone (JH).
- This suggests the existence of a new class of juvenile peptide hormones in lepidopteran insects.
