Ornithine decarboxylase activity in chick duodenum induced by 1 alpha, 25-dihydroxycholecalciferol.
Ornithine decarboxylase activity in chick duodenum induced by 1 alpha, 25-dihydroxycholecalciferol.
复制标题
1α，25-二羟基胆钙化醇诱导小鸡十二指肠中鸟氨酸脱羧酶活性。
作者：
T. Shinki;N. Takahashi;C. Miyaura;K. Samejima;Y. Nishii;T. Suda
研究了维生素D缺乏雏鸡十二指肠粘膜中胆钙化醇及其代谢产物对鸟氨酸脱羧酶活性的影响。十二指肠鸟氨酸脱羧酶活性下降的动物喂养的维生素D缺乏的饮食和其延迟的活动增加剂量依赖性的单次注射胆钙化醇。在测试的胆钙化醇的各种代谢物中，1 α，25-二羟基胆钙化醇[ 1 α，25（OH）2D 3]是最有效的刺激剂。在静脉注射1 α，25（OH）2D 3后2小时就检测到酶活性的刺激，并在6小时达到最大值。最大值比对照高27倍。此外，1 α 25（OH）2D 3治疗影响了十二指肠多胺含量。腐胺的含量增加到3倍，对照组后6小时的激素管理的值。亚精胺含量没有明显变化。1alpha，25（OH）2D 3的十二指肠鸟氨酸脱羧酶活性的增强与钙吸收的增强平行发生，这是在激素给药后3小时首次检测到。增强似乎是组织特异性的。在各肠段均观察到，但在十二指肠中最高。其他组织中的酶活性不受1 α，25（OH）2D 3的明显影响。这些结果清楚地表明，多胺的十二指肠生物合成的1 α，25（OH）2D 3的调节，这表明，十二指肠鸟氨酸脱羧酶可能参与钙的吸收机制的可能性。
The effect of cholecalciferol and its metabolites on ornithine decarboxylase activity was investigated in the duodenal mucosa of vitamin D-deficient chicks. The duodenal ornithine decarboxylase activity decreased in animals fed a vitamin D-deficient diet and its retarded activity was increased dose-dependently by a single injection of cholecalciferol. Among various metabolites of cholecalciferol tested, 1 alpha, 25-dihydroxycholecalciferol [ 1 alpha, 25 (OH)2D3] was the most potent stimulator. Stimulation of the enzyme activity was detected as early as 2h after intravenous administration of 1 alpha, 25 (OH)2D3 and a maximal value was attained at 6 h. The maximal value was 27 times higher than the control. In addition, treatment with 1 alpha 25 (OH)2D3 affected the duodenal content of polyamines. The content of putrescine increased to a value of three times that of the control 6 h after the hormone administration. The spermidine content did not change appreciably. The enhancement of duodenal ornithine decarboxylase activity by 1 alpha, 25 (OH)2D3 occurred in parallel with the enhancement of calcium absorption, which was first detected 3 h after the hormone administration. The enhancement appeared to be tissue-specific. It was observed in every intestinal segment, but was highest in the duodenum. Enzyme activity in other tissues was not influenced appreciably by 1 alpha, 25 (OH)2D3. These results clearly indicate that the duodenal biosynthesis of polyamines is regulated by 1 alpha, 25 (OH)2D3, suggesting the possibility that duodenal ornithine decarboxylase may be involved in the calcium absorption mechanism.