Smekens M, Dumont J E, Degeyter A, Galand P
Biochim Biophys Acta. 1986 Aug 1;887(3):341-4. doi: 10.1016/0167-4889(86)90164-3.
Interferon-induced 2-5A synthetase is also present in various cells and tissues in the absence of any interferon treatment. The activity of this enzyme, which synthesizes a series of oligoadenylates, ppp(A2'p)n5'A (collectively referred to as 2-5A), was previously shown to vary with the growth status of liver tissue i.e., it decreased before and during the peak of DNA synthesis activity induced in rat liver by a two third hepatectomy. In the course of studies aimed at testing the hypothesis that 2-5A synthetase activity might exert negative control on normal cell growth and multiplication, we show here that a treatment of ovariectomized rats with a single dose of estradiol-17beta (100 micrograms/100 g body weight) induced a transient increase in the [3H]thymidine labelling index in the liver after 24 h and markedly decreased the 2-5A synthetase activity. A time course study revealed that 2-5A synthetase activity started to decrease after 3 h, reaching a minimal value (10% of the control level) after 12 h, then slowly increased to come back to control level at 48 h. These results, together with our similar data on regenerating liver, suggest that low 2-5A synthetase activity is permissive for acquisition of proliferative 'competence' by G0 cells.
在未进行任何干扰素处理的情况下，干扰素诱导的2-5A合成酶也存在于各种细胞和组织中。该酶可合成一系列寡聚腺苷酸，即ppp(A2'p)n5'A（统称为2-5A），其活性先前已表明会随肝组织的生长状态而变化，也就是说，在大鼠肝脏三分之二肝切除诱导的DNA合成活性高峰之前及期间，该酶活性会降低。在旨在验证2-5A合成酶活性可能对正常细胞生长和增殖发挥负调控这一假说的研究过程中，我们在此表明，用单剂量的17β-雌二醇（100微克/100克体重）处理去卵巢大鼠，24小时后肝脏中[3H]胸苷标记指数会出现短暂升高，且2-5A合成酶活性会显著降低。一项时间进程研究显示，2-5A合成酶活性在3小时后开始下降，12小时后降至最低值（对照水平的10%），然后缓慢上升，在48小时时恢复到对照水平。这些结果，连同我们关于再生肝脏的类似数据，表明低2-5A合成酶活性有利于G0细胞获得增殖“能力”。
