肝刺激物质对原代大鼠肝细胞DNA合成的影响

STIMULATORY ACTIVITY OF HSS ON DMA SYNTHESIS IN PRIMARY CULTURE OF ADULT RAT HEPATOCYTES

作者确定了肝刺激因子(HSS)的存在,以及其刺激肝细胞DNA合成效应的作用特点。从作68％肝切除24h后的成年大鼠残留肝中提取HSS,在原代成年大鼠肝细胞无血清培养中可使~3H-TdR掺入升高1.5～3.1倍,效应的表达在一定剂量范围内随剂量的增加而增加;峰值后,随剂量增加而减弱,但未出现抑制效应。时效关系呈双相反应,第一峰时为24h,第二峰时为48h。放射自显影证实,所掺入的~3H-TdR位于细胞核内,是DNA复制合成的结果,肝细胞从G_1期进入S期的速率K G_1/S为基础状态的1.9倍。

The presence of hepatic stimulatory substance (HSS) has been identified in our laboratory and the characteristics of its stimulatory activity on DNA synthesis in serum-free culture of adult rat hepatocy-tes were demonstrated.The HSS was extracted from the remaining adult rat livey 24hafter a hepatec-tomy of 68% a l.5~3.1 fold increase was produced by incorporating 3H Thymidine into the hepatic DNA of the adult rat hepatocyte culture.The activity index of HSS increased with the rising dose to a maximum value but then decreased at higher doses.However,no inhibition was detected at any dose of HSS.The time-dependent effect presented a biphasic response revealing peaks of stimulation by 3H-TdR incorporation into the DNA at 24h and 48h after addition of HSS to t'le cultures.Autoradiography demonstrated that the incorporated isotope was located exclusively in the nuclear DNA as the resulte of DNA raplication.The rale of entering into the S phase from G1 phase (G1/S) was 1.9 limes that of the basal state.