Kido H, Fukusen N, Katunuma N
Biochemistry. 1987 Apr 21;26(8):2349-53. doi: 10.1021/bi00382a041.
In adrenalectomized rats, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) markedly enhanced the inductions of tyrosine aminotransferase (TAT) and ornithine decarboxylase by glucocorticoids, even with sufficient concentration of glucocorticoids to have a maximal effect, whereas it had no effect on TAT activity and increased ornithine decarboxylase activity only slightly in the absence of glucocorticoids. Phorbol derivatives and components of TPA such as 4 beta-phorbol, phorbol 12-tetradecanoate, phorbol 13-acetate, and 4-O-methylphorbol 12-tetradecanoate 13-acetate, which have no tumor-promoting activity or ability to activate protein kinase C, did not have any effect on TAT induction by glucocorticoid. TPA enhanced the induction of TAT by various glucocorticoids but had no effect on induction of TAT by glucagon or insulin and did not enhance the induction of glucose-6-phosphate dehydrogenase by 17 beta-estradiol. These results suggest that TPA specifically enhances the induction of TAT and ornithine decarboxylase by glucocorticoids. Similar effects of TPA on TAT induction by glucocorticoid were observed in primary cultures of adult rat hepatocytes. Another activator of protein kinase C, rac-1,2-dioctanoylglycerol, was also found to have similar effects on the cells.
在肾上腺切除的大鼠中，促肿瘤佛波酯12 - O - 十四烷酰佛波醇13 - 乙酸酯（TPA）显著增强了糖皮质激素对酪氨酸转氨酶（TAT）和鸟氨酸脱羧酶的诱导作用，即便糖皮质激素浓度已足以产生最大效应；而在没有糖皮质激素的情况下，TPA对TAT活性没有影响，仅略微增加鸟氨酸脱羧酶活性。佛波醇衍生物以及TPA的组分，如4β - 佛波醇、佛波醇12 - 十四烷酸酯、佛波醇13 - 乙酸酯和4 - O - 甲基佛波醇12 - 十四烷酸酯13 - 乙酸酯，它们没有促肿瘤活性或激活蛋白激酶C的能力，对糖皮质激素诱导TAT没有任何影响。TPA增强了各种糖皮质激素对TAT的诱导作用，但对胰高血糖素或胰岛素诱导TAT没有影响，并且不增强17β - 雌二醇对葡萄糖 - 6 - 磷酸脱氢酶的诱导作用。这些结果表明，TPA特异性增强了糖皮质激素对TAT和鸟氨酸脱羧酶的诱导作用。在成年大鼠肝细胞原代培养物中也观察到TPA对糖皮质激素诱导TAT有类似作用。蛋白激酶C的另一种激活剂rac - 1,2 - 二辛酰甘油对细胞也有类似作用。
