Nadal C, Lombard M N, Zajdela F
Virchows Arch B Cell Pathol. 1976 May 26;20(4):277-85. doi: 10.1007/BF02890346.
Inhibition of the G1-S transition in synchronized baby rat hepatocytes was obtained by a subcutaneous injection of adult rat liver cytosol. This inhibitory activity was observed only with liver cytosol and not with kidney or spleen cytosol. The liver cell was a relatively specific target: no modifications were recorded in the kidney or submaxillary gland and inconsistant variations were found with tongue epithelium. The activity was associated with a non-dialysable factor. Physiological investigations support the opinion that the liver factor is the origin of the serum factor which had previously been described. Both factors were absent during the first three weeks of life. They appeared together during the 4th week in correlation with a decreasing rate of liver cell multiplication and then reached progressively their definitive adult levels. After 2/3 hepatectomy in adults, the liver cytosol retained its inhibitory activity, but the serum factor was reversibly neutralized by an antagonistic factor. Both inhibitory factors could be prematurely induced in baby rats and appeared transiently during the period of low mitotic activity following a wave of synchronized liver cells generated by an irritating stress. This inhibitory system is characteristic of the last developmental stages of the liver when growth decelerates before reaching a steady state. It seems to reduce the multiplication of hepatocytes by decreasing their sensitivity to stimuli initiating cell replication.
通过皮下注射成年大鼠肝细胞溶胶，可抑制同步化新生大鼠肝细胞从G1期向S期的转变。仅在肝细胞溶胶中观察到这种抑制活性，而在肾或脾细胞溶胶中未观察到。肝细胞是相对特异的靶点：在肾或颌下腺中未记录到变化，在舌上皮中发现不一致的变化。该活性与一种不可透析的因子有关。生理学研究支持这样一种观点，即肝脏因子是先前描述的血清因子的来源。这两种因子在出生后的前三周均不存在。它们在第4周同时出现，与肝细胞增殖速率的下降相关，然后逐渐达到其确定的成年水平。成年大鼠2/3肝切除后，肝细胞溶胶保留其抑制活性，但血清因子被一种拮抗因子可逆性中和。这两种抑制因子均可在新生大鼠中过早诱导，并在由刺激性应激产生的一波同步化肝细胞后的低有丝分裂活性期短暂出现。这种抑制系统是肝脏最后发育阶段的特征，此时生长在达到稳定状态之前减速。它似乎通过降低肝细胞对启动细胞复制的刺激的敏感性来减少肝细胞的增殖。
