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Cross reactivity studies of CRF-related peptides on insect Malpighian tubules
Abstract:
Manduca sexta diuretic peptide II (Mas-DPII) stimulates fluid secretion by adult Malpighian tubules and cyclic AMP production by larval proximal and adult tubules of M. sexta in a dose-dependent manner. Mas-DPII has no effect on fluid transport across the larval cryptonephric complex. M. sexta diuretic hormone (Mas-DH) and CRF-related insect diuretic peptides from Acheta domesticus, Locusta migratoria, and Periplaneta americana also cause similar increases in the production of cyclic AMP by the Malpighian tubules of both larval and adult M. sexta. Insect CRF-related diuretic peptides exhibit varying degrees of potency when assayed on Malpighian tubules from L. migratoria and A. domesticus. Sauvagine, bovine-CRF, and human-CRF have only a small, but significant, effect on cyclic AMP production by M. sexta Malpighian tubules. However, sauvagine, bovine-CRF, and sucker fish urotensin-I have no effect on L. migratoria tubules. Stimulation of cyclic AMP production by M. sexta Malpighian tubules could potentially be used as a screening assay to identify other insect CRF-related diuretic peptides.
Insights
Manduca sexta diuretic peptide II (Mas-DPII) and related insect peptides stimulate cyclic AMP production in Manduca sexta Malpighian tubules. This effect may aid in discovering new insect diuretic peptides.
Area of Science:
- Insect physiology
- Endocrinology
- Molecular biology
Background:
- Malpighian tubules are key osmoregulatory organs in insects.
- Diuretic peptides regulate fluid and ion transport.
- CRF-related peptides are conserved signaling molecules across species.
Purpose of the Study:
- To investigate the effects of Mas-DPII on Manduca sexta Malpighian tubules.
- To compare the activity of Mas-DPII with other insect diuretic peptides and vertebrate CRFs.
- To explore the potential of M. sexta Malpighian tubules as a model for screening new diuretic peptides.
Main Methods:
- Dose-dependent assays of Mas-DPII on larval and adult M. sexta Malpighian tubules.
- Measurement of cyclic AMP production in response to various peptides.
- Comparative analysis of peptide activity across different insect species and with vertebrate CRFs.
Main Results:
- Mas-DPII stimulates fluid secretion and cyclic AMP production in adult M. sexta Malpighian tubules.
- Mas-DPII does not affect larval cryptonephric complex fluid transport.
- Other insect CRF-related peptides also increase cyclic AMP in M. sexta tubules, with varying potencies.
- Vertebrate CRFs show minimal effect on M. sexta tubules, and no effect on L. migratoria tubules.
Conclusions:
- Mas-DPII is a potent stimulator of M. sexta Malpighian tubule function.
- Insect CRF-related peptides share functional similarities in regulating Malpighian tubule activity.
- M. sexta Malpighian tubule cyclic AMP production is a viable assay for identifying novel insect diuretic peptides.
