Matsuzaki S, Suzuki M, Hamana K
Acta Endocrinol (Copenh). 1981 Sep;98(1):57-61. doi: 10.1530/acta.0.0980057.
Effect of chronic methylthiouracil (MTU) treatment on the thyroid arginase activity and thyroidal concentration of arginine, ornithine and other amino acids was studied in the rat. The activity of thyroid arginase increased significantly at 15 days of MTU treatment and the elevated enzyme activity was reduced to normal by L-thyroxine (T4) injection. The thyroidal concentration of polyamines was increased by MTU and decreased by T4 with the exception of spermine. The thyroidal concentration of arginine and lysine, a substrate and an inhibitor for arginase respectively decreased significantly, while that of ornithine remained unchanged after MTU treatment. T4 injected to MTU-pretreated rats restored the decreased arginine concentration to normal. These results suggest that ornithine supply for polyamine biosynthesis is regulated by the level of both arginase and lysine in the thyroid.
在大鼠中研究了慢性甲硫氧嘧啶（MTU）治疗对甲状腺精氨酸酶活性以及甲状腺中精氨酸、鸟氨酸和其他氨基酸浓度的影响。MTU治疗15天时，甲状腺精氨酸酶活性显著增加，注射L-甲状腺素（T4）后升高的酶活性恢复正常。除精胺外，MTU使甲状腺中多胺浓度增加，T4使其降低。MTU治疗后，精氨酸（精氨酸酶的底物）和赖氨酸（精氨酸酶的抑制剂）的甲状腺浓度分别显著降低，而鸟氨酸浓度保持不变。给MTU预处理的大鼠注射T4可使降低的精氨酸浓度恢复正常。这些结果表明，甲状腺中多胺生物合成的鸟氨酸供应受精氨酸酶和赖氨酸水平的调节。
