Laskowska-Klita T, Bong M
Horm Metab Res. 1981 Mar;13(3):155-7. doi: 10.1055/s-2007-1019204.
During the first four days after unilateral nephrectomy the free tyrosine content in plasma, liver and hypertrophic kidney was decreased by more than 50% as compared with the values observed in intact rat. After sham operation, the content of tyrosine was decreased to the same extent. The activity of tyrosine aminotransferase in liver was doubled two days after sham operation: no such increase was observed after unilateral nephrectomy. At the same time a decline of the enzyme activity in kidney was demonstrated after both types of surgery. Hydrocortisone in a single i.p. dose stimulated enzyme activity in the liver of intact rats three-fold, and more than four-fold after nephrectomy and sham operation. In kidney of intact rat, as a result of hydrocortisone treatment, the enzyme activity was doubled; it was, however, insensitive to this treatment after unilateral nephrectomy, and increased only by 20% after sham operation. It is suggested that the changes in tyrosine content and tyrosine aminotransferase activity observed after unilateral nephrectomy were not due to stress alone, but underwent regulation aimed at assuring a sufficient level of this amino acid for metabolism.
在单侧肾切除后的头四天，与完整大鼠相比，血浆、肝脏和肥大肾脏中的游离酪氨酸含量降低了50%以上。假手术后，酪氨酸含量也降低到相同程度。假手术后两天，肝脏中酪氨酸转氨酶的活性增加了一倍：单侧肾切除后未观察到这种增加。同时，两种手术类型后均显示肾脏中该酶活性下降。单次腹腔注射氢化可的松可使完整大鼠肝脏中的酶活性增加三倍，肾切除和假手术后增加四倍以上。在完整大鼠的肾脏中，氢化可的松治疗使酶活性增加了一倍；然而，单侧肾切除后对该治疗不敏感，假手术后仅增加20%。有人认为，单侧肾切除后观察到的酪氨酸含量和酪氨酸转氨酶活性的变化并非仅由应激引起，而是受到旨在确保该氨基酸有足够代谢水平的调节。
