Payraudeau V, Sarsat J P, Sobczak J, Bréchot C, Albaladéjo V
Rhône-Poulenc Rorer, Département Sécurité du Médicament, Vitry/Seine, France.
Mol Cell Endocrinol. 1998 Aug 25;143(1-2):107-16. doi: 10.1016/s0303-7207(98)00136-1.
The time-course of c-myc and cyclin A2 mRNA expression was determined in the liver of male Sprague-Dawley rats during transient liver cell proliferation induced by a single dose of ethinyl estradiol (EE), and was compared to that during liver regeneration following two-thirds hepatectomy (PH). Cell proliferation was assessed in terms of 5'-bromodeoxyuridine (BrdU) labeling. EE administration and PH both increased BrdU labeling between 18 and 48 h, with peak values at 18 and 24 h. An early (2 h) increase in BrdU labeling was observed after EE but not PH. Maximal increases in cyclin A2 mRNA levels and BrdU labeling coincided after both EE and PH, and cyclin A2 mRNA expression was proportional to the intensity of the proliferative response. In contrast, the degree of c-myc mRNA expression was similar after EE administration and PH, but the time course was different: c-myc gene expression rose concomitantly with DNA replication after EE, while after PH it increased during the prereplicative phase. This indicates that the pattern of c-myc gene expression in the liver is strongly related to the type of proliferative response.
在雄性Sprague-Dawley大鼠中，测定了单剂量乙炔雌二醇（EE）诱导的短暂肝细胞增殖过程中肝脏中c-myc和细胞周期蛋白A2 mRNA表达的时间进程，并与三分之二肝切除（PH）后肝脏再生过程中的时间进程进行了比较。通过5'-溴脱氧尿苷（BrdU）标记评估细胞增殖。给予EE和进行PH后，BrdU标记在18至48小时之间均增加，峰值分别出现在18小时和24小时。给予EE后观察到BrdU标记在早期（2小时）增加，但PH后未观察到。EE和PH后细胞周期蛋白A2 mRNA水平和BrdU标记的最大增加同时出现，并且细胞周期蛋白A2 mRNA表达与增殖反应强度成正比。相比之下，给予EE和PH后c-myc mRNA表达程度相似，但时间进程不同：给予EE后c-myc基因表达与DNA复制同时上升，而PH后在复制前期增加。这表明肝脏中c-myc基因表达模式与增殖反应类型密切相关。
