Mankowitz L, Castro V M, Mannervik B, Rydström J, DePierre J W
Department of Biochemistry, Wallenberg Laboratory, University of Stockholm, Sweden.
Biochem J. 1990 Jan 1;265(1):147-54. doi: 10.1042/bj2650147.
The effect of hypophysectomy and subsequent treatment with adrenocorticotropic hormone (adrenocorticotropin, ACTH) on the isoenzymes of glutathione transferase in the rat adrenal gland was investigated. A large increase (approx. 11-fold) in the level of transferase subunit 4 was observed in hypophysectomized animals by immunoblotting. When the activity of glutathione transferase 4-4 was measured in adrenal cytosol using trans-stilbene oxide as a selective substrate, a 15-fold increase was noted. Lack of the pituitary hormone ACTH is apparently related to this increase, since treatment of hypophysectomized animals with ACTH for 2 weeks partially down-regulated subunit 4. Glutathione transferase subunits 3 and 8 in the adrenal were also increased in amount by hypophysectomy, but not at all to the same extent. The activity of glutathione transferase 4-4 was elevated also in the liver and ovary (5 and 1.5 times respectively) after hypophysectomy. These elevated enzyme levels were, however, not affected by ACTH treatment. This down-regulation of glutathione transferases in the rat adrenal by ACTH may be related to the fact that, under normal conditions, this organ is highly susceptible to the toxic effects of various polycyclic hydrocarbons, whereas under circumstances where there is no ACTH production, as in hypophysectomized rats, the adrenal is resistant to these same hydrocarbons.
研究了垂体切除及随后用促肾上腺皮质激素（促肾上腺皮质素，ACTH）治疗对大鼠肾上腺谷胱甘肽转移酶同工酶的影响。通过免疫印迹法观察到，垂体切除的动物中转移酶亚基4的水平大幅升高（约11倍）。当使用反式氧化 stilbene作为选择性底物在肾上腺胞质溶胶中测量谷胱甘肽转移酶4-4的活性时，发现其活性增加了15倍。垂体激素ACTH的缺乏显然与这种增加有关，因为用ACTH治疗垂体切除的动物2周可使亚基4部分下调。垂体切除还使肾上腺中的谷胱甘肽转移酶亚基3和8的量增加，但程度不同。垂体切除后，肝脏和卵巢中的谷胱甘肽转移酶4-4的活性也升高（分别为5倍和1.5倍）。然而，这些升高的酶水平不受ACTH治疗的影响。ACTH对大鼠肾上腺中谷胱甘肽转移酶的这种下调可能与以下事实有关：在正常情况下，该器官对各种多环烃的毒性作用高度敏感，而在没有ACTH产生的情况下，如垂体切除的大鼠，肾上腺对这些相同的烃具有抗性。
