Guihot G, Blachier F
Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
Mol Cell Biochem. 1997 Oct;175(1-2):143-8. doi: 10.1023/a:1006895931091.
To study the metabolic fate of L-histidine and histamine in rat isolated enterocytes, enterocytes were incubated in the presence of 0.1 mM L-[U-14C] histidine. At the rate of 11.1 +/- 2.7 pmol/10(6) cells/30 min, the amino acid was incorporated into cellular proteins. 80 microM cycloheximide, i.e. a protein synthesis inhibitor, inhibited this incorporation by 70 +/- 17%. L-histidine was used for cellular protein synthesis which depended on time and concentration. 0.1 mM L-[U-14C] histidine was little oxidized by intestinal cells, i.e. 0.12 +/- 0.06 pmol/10(6) cells/30 min, and was not converted into histamine. When 10 mM histamine was added to the incubation medium, it completely inhibited the incorporation of 0.1 mM [1,4-14C] putrescine into isolated enterocytes. In enterocyte homogenates, this corresponded to inhibition by histamine of putrescine incorporation as catalyzed by transglutaminase activity. Since histamine incorporation into TCA-precipitable material derived from enterocyte homogenates depended on time and concentration, we concluded that exogenous, but not de novo-formed histamine was able to compete with putrescine incorporation into enterocytes as catalyzed by transglutaminase activity.
为研究L-组氨酸和组胺在大鼠离体肠上皮细胞中的代谢命运，将肠上皮细胞在0.1 mM L-[U-¹⁴C]组氨酸存在的情况下进行孵育。该氨基酸以11.1±2.7 pmol/10⁶个细胞/30分钟的速率掺入细胞蛋白质中。80 μM环己酰亚胺，即一种蛋白质合成抑制剂，使这种掺入受到70±17%的抑制。L-组氨酸用于细胞蛋白质合成，这取决于时间和浓度。0.1 mM L-[U-¹⁴C]组氨酸很少被肠细胞氧化，即0.12±0.06 pmol/10⁶个细胞/30分钟，并且不会转化为组胺。当向孵育培养基中加入10 mM组胺时，它完全抑制了0.1 mM [1,4-¹⁴C]腐胺掺入离体肠上皮细胞。在肠上皮细胞匀浆中，这相当于组胺对转谷氨酰胺酶活性催化的腐胺掺入的抑制作用。由于组胺掺入源自肠上皮细胞匀浆的三羧酸循环沉淀物质取决于时间和浓度，我们得出结论，外源性组胺而非新形成的组胺能够与转谷氨酰胺酶活性催化的腐胺掺入肠上皮细胞的过程竞争。
