Stimulus-secretion coupling of arginine-induced insulin release. Metabolism of L-arginine and L-ornithine in pancreatic islets.
Exogenous L-arginine and L-ornithine rapidly accumulate in rat pancreatic islets. L-Arginine is converted to L-ornithine and urea. Endogenous or exogenous L-ornithine generates di- and polyamines, the putrescine turnover being faster than that of spermidine and spermine. However, the major pathway for L-ornithine metabolism consists of its transamination to L-glutamaldehyde and further conversion to L-glutamate. The amines and L-glutamate derived from exogenous L-ornithine are incorporated into islet proteins at the intervention of transglutaminase and cycloheximide-sensitive biosynthetic processes, respectively. These findings suggest the hypothesis that the insulinotropic action of L-arginine and L-ornithine could somehow be related to the metabolism of these cationic amino acids in islet cells.
Malaisse
W J
WJ
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Blachier
F
F
Mourtada
A
A
Camara
J
J
Albor
A
A
Valverde
I
I
Sener
A
A
D000818:Animals; D001119:Arginase / Q000378:metabolism; D001120:Arginine / Q000378:metabolism* / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D005971:Glutamates / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D007515:Islets of Langerhans / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008954:Models, Biological; D009952:Ornithine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D010084:Oxidation-Reduction; D011073:Polyamines / Q000096:biosynthesis; D051381:Rats; D014508:Urea / Q000096:biosynthesis
D005971:Glutamates; D007328:Insulin; D011073:Polyamines; C025025:alpha-methylornithine; D014508:Urea; D001120:Arginine; D009952:Ornithine; D001119:Arginase; D005947:Glucose