By inducing 3t3 - l1 preadipocyte with individual hormone , it was identified that the mitotic clonal expansion was induced only by insulin , not by 1 - isobutyl - 3 - methylxanthine or dexamethasone 有报道用药物抑制了克隆扩增的同时抑制了细胞的分化。我们发现克隆扩增是仅由胰岛素诱导引起的。
2.
However , significant fraction of 3t3 - l1 preadipocytes differentiated into adipocytes without the mitotic clonal expansion when the preadipocytes were induced with the combination of 1 - isobutyl - 3 - methylxanthine and dexamethasone 用地塞米松和ibmx对细胞进行诱导不发生克隆扩增，而细胞也能部分分化，分化形成的脂肪细胞未经过dna复制。
3.
Upon the differentiation induction of 3t3 - l1 preadipocytes by hormone cocktail containing 1 - isobutyl - 3 - methylxanthine , dexamethasone and insulin , the preadipocytes undergo ~ 2 rounds of mitotic clonal expansion , which just precedes the adipogenic gene expression program and has been thought to be an essential early step for differentiation initiation 诱导分化的早期细胞会进行约两轮的细胞分裂，被称为克隆扩增。克隆扩增以前一直被认为可能有利于染色体的重构以易化分化所需要的基因表达，因此克隆扩增可能是3t3 l1前脂肪细胞分化所必需的过程。
4.
Rat cumulus - enclosed oocyte ( ceo ) and denuded oocyte ( do ) both spontaneously resume meiotic maturation in vitro , when cultured for 2h , the germinal vesical breakdown percentage of do reaches up to 88 % , and ceos get 53 % . oocytes begin to extrude first polar body 1 ( fb1 ) when cultured for 8h . mouse oocyte spontaneous maturation in vitro can be inhibited by 4mm hypoxanthine ( hx ) or 25um 3 - isobutyl - methylxanthine ( ibmx ) . while , 4mm hx can not inhibit the spontaneous maturation of rat oocyte , and the lowest effective concentration of ibmx to inhibit rat oocyle spontaneous maturation in vitro is 50um . treated with the same concentration of ibmx , gvbd percentage of rat ceo is lower than that of do , the results indicat that cumulus cells delay rat oocyte spontaneous maturation and potentate the inhibition effect of ibmx , but it ' s not the case on mouse Ceo和do培养8h时都开始排出pb1 ；在卵母细胞成熟抑制模型中， 4mm次黄嘌呤( hx )和25 m的异丁基甲基黄嘌呤( ibmx )是小鼠卵母细胞成熟的有效抑制剂，但4mm的hx抑制大鼠卵母细胞成熟效果不理想，用hx - m199和hx - mem培养24h ， gvbd率分别为61 ， 81 ，而ibmx有效抑制大鼠卵母细胞自发成熟的最小浓度为50 m ， ibmx可以降低大鼠ceo和do的gvbd率，但ceo中的卵母细胞gvbd率要显著低于do的gvbd率， 100 m的jbmx处理24h后，大鼠ceo和do的gvbd率分别为24 ， 84 ，提示卵丘细胞的存在可以延迟大鼠卵母细胞的自发成熟，有助于抑制卵母细胞成熟，但在小鼠上ceo和do的自发成熟差异不明显。
