Svec F
Mol Cell Endocrinol. 1984 Apr;35(1):33-40. doi: 10.1016/0303-7207(84)90027-3.
The effect of steroids on the growth of AtT-20 mouse pituitary tumor cells was investigated. It was found that under certain conditions glucocorticoids inhibit growth. Specificity studies indicated that only glucocorticoids caused this effect. Biopotency studies indicated that dexamethasone had its mid-maximal effect around 5 nM. At least part of this inhibition was caused by a decrease in the cell's ability to synthesize DNA; glucocorticoids inhibit the rate at which tritiated thymidine is incorporated into TCA-precipitable material. The magnitude of the growth-inhibiting effect depended upon the prior culture history of the cell. The effect was least on cells derived from exponentially growing cultures and most effective on cells derived from cultures that were approaching their density limit. It is concluded that glucocorticoids inhibit AtT-20 cell growth by interfering with their ability to transform from confluent cultures to ones that grow exponentially. The significance of this finding is that now two mechanisms must be considered when investigating the pathways through which glucocorticoids decrease the ACTH production of the AtT-20 cell.
研究了类固醇对AtT - 20小鼠垂体肿瘤细胞生长的影响。发现在某些条件下，糖皮质激素会抑制生长。特异性研究表明，只有糖皮质激素会产生这种效应。生物效价研究表明，地塞米松在5 nM左右达到其最大效应的一半。这种抑制作用至少部分是由于细胞合成DNA的能力下降所致；糖皮质激素抑制了氚标记胸腺嘧啶核苷掺入三氯乙酸沉淀物质的速率。生长抑制作用的大小取决于细胞的先前培养历史。对来自指数生长培养物的细胞影响最小，对来自接近密度极限的培养物的细胞影响最有效。结论是，糖皮质激素通过干扰AtT - 20细胞从汇合培养物转变为指数生长培养物的能力来抑制其生长。这一发现的意义在于，在研究糖皮质激素降低AtT - 20细胞促肾上腺皮质激素分泌的途径时，现在必须考虑两种机制。
