Malaisse W J, Blachier F, Mourtada A, Camara J, Albor A, Valverde I, Sener A
Laboratory of Experimental Medicine, Brussels Free University, Belgium.
Biochim Biophys Acta. 1989 Sep 19;1013(2):133-43. doi: 10.1016/0167-4889(89)90041-4.
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.
外源性L-精氨酸和L-鸟氨酸在大鼠胰岛中迅速积累。L-精氨酸被转化为L-鸟氨酸和尿素。内源性或外源性L-鸟氨酸生成二胺和多胺，腐胺的周转速度比亚精胺和精胺快。然而，L-鸟氨酸代谢的主要途径是将其转氨生成L-谷氨醛，再进一步转化为L-谷氨酸。分别在转谷氨酰胺酶和环己酰亚胺敏感的生物合成过程的干预下，源自外源性L-鸟氨酸的胺类和L-谷氨酸被整合到胰岛蛋白质中。这些发现提示了这样一个假说，即L-精氨酸和L-鸟氨酸的促胰岛素作用可能在某种程度上与胰岛细胞中这些阳离子氨基酸的代谢有关。
