Thyroxine and cortisone cooperate to modulate postnatal intestinal enzyme differentiation in the rat.
Thyroxine and cortisone cooperate to modulate postnatal intestinal enzyme differentiation in the rat.
复制标题
甲状腺素和可的松协同调节大鼠出生后肠道酶的分化。
DOI：
10.1152/ajpgi.1991.260.3.g371
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Holt,PR
中科院分区：
文献类型：
--
作者：
Yeh,KY;Yeh,M;Holt,PR
研究了可的松和甲状腺素（T4）在大鼠出生后早期空肠蔗糖酶和乳糖酶表达调节中的相互作用。可的松（50微克/克体重）在第5-16天提前诱导蔗糖酶活性，并在此后的第22天增强活性。T4（1微克/克）加可的松在第9天或更年轻的大鼠中引起更大的蔗糖酶表达。直到第13天T4才诱导蔗糖酶表达。在第9天的大鼠中，可的松提高了乳糖酶活性，添加T4后这种作用消失。第19、22天，可的松抑制大鼠乳糖酶；添加T4后，乳糖酶活性进一步降低。直到第19天，单独使用T4均不能抑制乳糖酶活性。空肠酶含量测定显示，第22天蔗糖酶的催化活性高于19天或更年轻的大鼠，而T4大鼠的催化活性低于可的松。相比之下，所有动物组的乳糖酶活性保持不变。用第9天大鼠进行的体内[35S]蛋氨酸标记研究表明，可的松诱导蔗糖酶的重新合成，并增加35S并入乳糖酶。可的松加T4进一步增加了35S入蔗糖酶，并显著增加了35S入乳糖酶。我们认为，1)可的松和T4在出生后早期共同刺激蔗糖酶的表达，降低乳糖酶的活性；2)乳糖酶活性的降低伴随着乳糖酶合成的增加，表明可的松和T4在翻译后水平调节乳糖酶的活性。
Interactions of cortisone and thyroxine (T4) in modulating jejunal sucrase and lactase expression were studied in rats during early postnatal life. Cortisone (50 micrograms/g body wt) precociously induced sucrase activity in days 5-16 rats and enhanced activity thereafter until day 22. T4 (1 microgram/g) plus cortisone evoked greater sucrase expression in day 9 or younger rats. T4 did not induce sucrase expression until day 13. Lactase activity was enhanced in rats younger than day 9 by cortisone, and this effect was abolished when T4 was added. In days 19 and 22 rats, cortisone depressed lactase; with T4, lactase activity was further decreased. T4 alone did not suppress lactase activity until day 19. Quantitation of jejunal enzyme content showed that sucrase catalytic activity was higher in day 22 than 19 or younger rats and lower in rats given T4 than cortisone. In contrast, lactase activity remained constant in all animal groups. In vivo [35S]methionine-labeling studies using day 9 rats showed that cortisone induced de novo synthesis of sucrase and increased 35S incorporation into lactase. Cortisone plus T4 increased 35S incorporation into sucrase further and significantly increased 35S incorporation into lactase. We conclude that 1) cortisone and T4 cooperatively stimulate sucrase expression and reduce lactase activity during early postnatal life and 2) reduction in lactase activity accompanied by increase in lactase synthesis suggests that cortisone and T4 regulate lactase activity at posttranslational level.