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Rat progastrin processing yields peptides with altered potency at the CCK-B receptor
David A Keire1, S Vincent Wu, David L Diehl
1CURE/UCLA Digestive Disease Research Center, West Los Angeles Veterans Administration Medical Center, Building 115, Room 117B, 11301 Wilshire Blvd, Los Angeles, CA 90073, USA.
Regulatory Peptides
|April 11, 2003
Summary
Rat progastrin processing yields gastrin-16, differing from other mammals due to proline residues. Sulfated gastrin forms exhibit higher CCK-B receptor affinity, potentially modulating biological activity.
Area of Science:
- Endocrinology
- Biochemistry
- Molecular Biology
Background:
- Prohormone processing dictates hormone function.
- Understanding gastrin molecular forms is key to its biological activity.
Purpose of the Study:
- To characterize molecular forms of rat gastrin.
- To elucidate the processing pathways of progastrin in rats.
Main Methods:
- Purification of rat gastrin from antral extracts.
- Gel permeation, anion exchange, and reverse-phase HPLC.
- Mass spectrometry and specific antisera for structural determination.
Main Results:
- Identified gastrin-16 as the primary form shorter than gastrin-17 in rats.
- Rat gastrin-16 processing is inhibited by proline residues, unlike in other mammals.
- Sulfated gastrin-16 and gastrin-17 show higher affinity for the CCK-B receptor.
Conclusions:
- Rat progastrin processing generates unique molecular forms.
- Sulfation significantly enhances gastrin binding to the CCK-B receptor.
- Progastrin processing variations influence gastrin's biological activity.