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Isolation, sequence, and bioactivity of chicken motilin
P De Clercq1, I Depoortere, M Macielag
1Gut Hormone Laboratory, K.U.L., Leuven, Belgium.
Peptides
|January 1, 1996
Summary
Chicken motilin, isolated from the small intestine, shows distinct receptor interactions compared to mammalian motilins. While it binds to rabbit receptors, chicken smooth muscle lacks demonstrable receptors but responds to chicken motilin with contractions.
Area of Science:
- Gastroenterology
- Comparative Physiology
- Endocrinology
Background:
- Motilin is a gastrointestinal peptide hormone regulating motility.
- Understanding species-specific variations in motilin function is crucial for comparative physiology.
- Previous studies have focused on mammalian motilin, leaving avian systems less explored.
Purpose of the Study:
- To isolate and characterize chicken motilin.
- To investigate the binding affinity and functional effects of chicken motilin on mammalian and avian smooth muscle.
- To compare chicken motilin's properties with those of mammalian motilins.
Main Methods:
- Isolation and purification of chicken motilin using chromatography techniques.
- Radioreceptor assays to determine binding affinities to motilin receptors.
- Tissue bath studies to assess the contractile effects of chicken motilin on smooth muscle strips.
Main Results:
- Chicken motilin sequence determined; differs from porcine motilin in six residues.
- Chicken motilin exhibits reduced but significant affinity for rabbit motilin receptors.
- Chicken smooth muscle lacks detectable motilin receptors but contracts dose-dependently to chicken motilin, blocked by verapamil.
Conclusions:
- Chicken motilin possesses distinct pharmacological properties compared to mammalian motilins.
- Avian and mammalian motilin systems exhibit significant functional and receptor differences.
- Chicken motilin's action on chicken jejunum suggests a unique signaling pathway independent of classical motilin receptors.