Sidransky H, Murty C N, Myers E, Verney E
Exp Mol Pathol. 1983 Jun;38(3):346-56. doi: 10.1016/0014-4800(83)90074-6.
The effect of a single tube feeding of L-tryptophan on hepatic ornithine decarboxylase (ODC) activity in rats was investigated. The levels of ODC activity in the livers of control and experimental rats were assayed in vitro by measuring the release of 14CO2 from DL-[1-14C]ornithine. Single tube feedings of varying levels of L-tryptophan (2.5-30 mg/100 g body wt) to overnight-fasted rats 1 hr before sacrifice exhibited increases in the hepatic ODC activities. L-Tryptophan (30 mg/100 g body wt) tube fed to overnight-fasted rats 1/6 to 12 hr before sacrifice induced hepatic ODC activities which were significantly elevated beginning at 1 hr and peaking at 2 hr (6.5-fold increase over controls). In vitro [14C]leucine incorporation into protein using hepatic microsomes of tryptophan-treated rats was significantly increased at 1 hr in comparison with that of controls. The tryptophan-induced stimulation of hepatic ODC activity was not affected by prior adrenalectomy but was abolished by pretreatment with cycloheximide. These studies demonstrate that a single feeding of L-tryptophan can significantly enhance in the rat the activity of ODC, a key enzyme in the biosynthesis of polyamines.
研究了单次经管饲给予L-色氨酸对大鼠肝脏鸟氨酸脱羧酶（ODC）活性的影响。在体外通过测量DL-[1-14C]鸟氨酸释放的14CO2来测定对照大鼠和实验大鼠肝脏中的ODC活性水平。在处死前1小时对禁食过夜的大鼠经管饲给予不同水平的L-色氨酸（2.5 - 30毫克/100克体重），结果显示肝脏ODC活性增加。在处死前1/6至12小时对禁食过夜的大鼠经管饲给予L-色氨酸（30毫克/100克体重），诱导的肝脏ODC活性在1小时开始显著升高，并在2小时达到峰值（比对照增加6.5倍）。与对照组相比，在1小时时，用色氨酸处理的大鼠肝脏微粒体在体外将[14C]亮氨酸掺入蛋白质的量显著增加。色氨酸诱导的肝脏ODC活性刺激不受预先肾上腺切除术的影响，但用环己酰亚胺预处理可消除该作用。这些研究表明，单次给予L-色氨酸可显著增强大鼠体内ODC的活性，ODC是多胺生物合成中的关键酶。
