Role of endopeptidase 3.4.24.16 in the catabolism of neurotensin, in vivo, in the vascularly perfused dog ileum.
1. The degradation of tritiated and unlabelled neurotensin (NT) following close intra-arterial infusion of the peptides in ileal segments of anaesthetized dogs was examined. 2. Intact NT and its catabolites recovered in the venous effluents were purified by chromatography on Sep-Pak columns followed by reverse-phase h.p.l.c. and identified by their retention times or by radioimmunoassay. 3. The half-life of neurotensin was estimated to be between 2 and 6 min. Four labelled catabolites, corresponding to free tyrosine, neurotensin (1-8), neurotensin (1-10) and neurotensin (1-11), were detected. 4. Neurotensin (1-11) was mainly generated by a phosphoramidon-sensitive cleavage, probably elicited by endopeptidase 24-11. 5. Two endopeptidase 3.4.24.16 inhibitors, phosphodiepryl 03 and the dipeptide Pro-Ile, dose-dependently potentiated the recovery of intact neurotensin. Furthermore, both agents inhibited the formation of neurotensin (1-10), the product that results from the hydrolysis of neurotensin by purified endopeptidase 3.4.24.16. In contrast, the endopeptidase 3.4.24.15 inhibitor Cpp-AAY-pAB neither protected neurotensin from degradation nor modified the production of neurotensin (1-10). 6. Our study is the first evidence to indicate that endopeptidase 3.4.24.16 contributes to the catabolism of neurotensin, in vivo, in the dog intestine.
Barelli
H
H
Institut de Pharmacologie Moléculaire et Cellulaire, UPR 411, CNRS Université de Nice Sophia Antipolis, Valbonne, France.
Fox-Threlkeld
J E
JE
Dive
V
V
Daniel
E E
EE
Vincent
J P
JP
Checler
F
F
D000595:Amino Acid Sequence; D000614:Aminocaproates / Q000494:pharmacology; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D005260:Female; D007082:Ileum / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000502:physiology*; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D009496:Neurotensin / Q000096:biosynthesis / Q000378:metabolism* / Q000493:pharmacokinetics; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000096:biosynthesis; D011480:Protease Inhibitors / Q000494:pharmacology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011863:Radioimmunoassay
D000614:Aminocaproates; C088409:N-(1-carboxyl-3-phenylpropyl)alanyl-alanyl-tyrosyl-4-aminobenzoate; D009842:Oligopeptides; D010446:Peptide Fragments; D011480:Protease Inhibitors; C077650:N-(phenylethylphosphonyl)-glycyl-prolyl-aminohexanoic acid; D009496:Neurotensin; C041969:neurotensin (1-10); D008666:Metalloendopeptidases; C062316:neurolysin; D011761:Pyrrolidonecarboxylic Acid