Discharge effect on pancreatic exocrine secretion produced by toxins purified from Tityus serrulatus scorpion venom

Three toxic polypeptides were purified from the venom of the Brazilian scorpion Tityus serrulatus by means of gel filtration in Sephadex G-50 and ion-exchange chromatography in carboxymethylcellulose. The peptides are basic molecules with molecular weights in the range of 7000 for which the amino ac...

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Bibliographic Details
Published in:The Journal of biological chemistry 1991-02, Vol.266 (5), p.3178-3185
Main Authors: L D Possani, B M Martin, M D Fletcher, P L Fletcher, Jr
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Amino Acids - analysis
Animals
Biological and medical sciences
Buthidae
Cell physiology
Chromatography, High Pressure Liquid
Electrophoresis, Polyacrylamide Gel
Fundamental and applied biological sciences. Psychology
Guinea Pigs
Microscopy, Electron
Molecular and cellular biology
Molecular Sequence Data
pancreas
Pancreas - drug effects
Pancreas - metabolism
Pancreas - ultrastructure
Scorpion Venoms - metabolism
scorpiones
Secretion. Exocytosis
Sequence Homology, Nucleic Acid
Toxins, Biological - toxicity
venom
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Summary:Three toxic polypeptides were purified from the venom of the Brazilian scorpion Tityus serrulatus by means of gel filtration in Sephadex G-50 and ion-exchange chromatography in carboxymethylcellulose. The peptides are basic molecules with molecular weights in the range of 7000 for which the amino acid compositions and sequences were determined. The effect of the purified peptides on pancreatic exocrine secretion in the guinea pig was studied. Biochemical measurements show that the cells are stimulated by these peptides to discharge their zymogen granules. Light and electron microscopic images confirm the biochemical measurements. At the light microscope level, acinar cells show dramatically fewer zymogen granules than in control pancreas with the appearance of large vacuoles and some loss of morphological integrity. Electron micrographs display apical regions devoid of zymogen granules and condensing vacuoles whereas acinar lumina contain crystalline secretory material. The secretory effect observed in vitro is comparable to that of carbamylcholine and that of the peptidergic secretagogue cholecystokinin-pancreozymin.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(18)49971-1