Singh V B, Kalimi M, Phan T H, Boadle-Biber M C
Department of Physiology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0551.
Mol Cell Neurosci. 1994 Apr;5(2):176-81. doi: 10.1006/mcne.1994.1019.
Bilateral infusion of dehydroepiandrosterone (DHEA) given intracerebroventricularly blocked the sound stress-induced increase in tryptophan hydroxylase activity observed ex vivo in midbrain and cortex but had no effect on the level of tryptophan hydroxylase activity from sham-stressed rats. DHEA (20 micrograms total dose) given bilaterally into the region of the central nucleus of the amygdala, 30 min prior to 1 h sound stress, also blocked the increase in enzyme activity in a dose-dependent manner. The DHEA treatment did not alter the activation of the enzyme seen in vitro in the presence of phosphorylating conditions. The effect of DHEA was steroid specific in that other sex steroids, such as estrogen, androgens, or progesterone, were without any effect. Coadministration, 20 micrograms each, of the potent glucocorticoid agonist, RU 28362, with DHEA 30 min prior to 1 h sound stress completely blocked the DHEA suppressive effect on sound stress-induced increases in tryptophan hydroxylase activity. The results obtained suggest that DHEA blocks this increase in tryptophan hydroxylase activity by antagonizing the effects of glucocorticoid.
脑室内双侧注射脱氢表雄酮（DHEA）可阻断在中脑和皮层中体外观察到的由声音应激诱导的色氨酸羟化酶活性增加，但对假应激大鼠的色氨酸羟化酶活性水平没有影响。在1小时声音应激前30分钟，双侧在杏仁核中央核区域注射DHEA（总剂量20微克），也以剂量依赖的方式阻断了酶活性的增加。DHEA处理并未改变在磷酸化条件下体外观察到的酶激活情况。DHEA的作用具有类固醇特异性，因为其他性类固醇，如雌激素、雄激素或孕酮，没有任何作用。在1小时声音应激前30分钟，将强效糖皮质激素激动剂RU 28362（每次20微克）与DHEA共同给药，完全阻断了DHEA对声音应激诱导的色氨酸羟化酶活性增加的抑制作用。所得结果表明，DHEA通过拮抗糖皮质激素的作用来阻断色氨酸羟化酶活性的这种增加。
