环核苷酸是分子生物学研究中颇受重视的细胞代谢系统,调节着细胞的生长、分裂和分化。本文综述了国外近年来的研究,认为细胞发生恶变时环核苷酸系统有着很大的改变,一般表现为细胞内 cAMP 环化酶活力减弱、cAMP 水平下降以及 cGMP 量的升高。在体外实验中发现 cAMP 可使肿瘤或转化细胞的形态逆转为正常细胞表型,并出现正常细胞的生化和功能特征。体内实验证明 cAMP 及其衍生物有抑制肿瘤生长的作用,目前不少实验企图用生物活性物质改变细胞内 cAMP 水平,以达到细胞逆转的目的,某些抗癌药物可以使肿瘤细胞中 cAMP 量增高,这显然与细胞分化有关。某些带瘤动物的尿中有大量 cGMP 排出,经手术、x 线和化学药物治疗后尿中排出量减少,故能以此判断治疗予后。 Cyclic nucleotides are highly valued cellular metabolic systems in molecular biology studies that regulate cell growth, division, and differentiation. In this paper, recent studies abroad have been reviewed. It is believed that the cyclic nucleotide system changes drastically when cells undergo malignant transformation. The general manifestation is the weakening of intracellular cAMP cyclase activity, the decrease of cAMP levels, and the increase of cGMP levels. In vitro experiments revealed that cAMP can reverse the morphology of tumors or transformed cells to normal cell phenotypes, and the appearance of normal cells has biochemical and functional features. In vivo experiments have demonstrated that cAMP and its derivatives inhibit the growth of tumors. At present, many experiments attempt to use bioactive substances to change intracellular cAMP levels in order to achieve the purpose of cell reversal. Some anticancer drugs can increase the amount of cAMP in tumor cells. This is obviously related to cell differentiation. Some tumor-bearing animals have a large amount of cGMP excreted in the urine. After surgery, x-rays, and chemical drugs treatment, the urinary excretion decreases, so it can be judged after treatment.