Armato U, Andreis P G, Draghi E
Chem Biol Interact. 1975 Aug;11(2):67-90. doi: 10.1016/0009-2797(75)90015-0.
The effect of a 24-h treatment with various doses (from 1.5-10-minus 8 to 3.0-10-minus 3 M) of adenosine 3',5'-cyclic monophospahte (cAMP) on morphometric parameters, [5--3H]uridine radioactivity concentration (URC), [methyl--3H]thymidine [Me--3H]-Tr) labelling index per hour (L.I./h) and per cent mitotic index (M.I.%) of young rat differentiated hepatocytes in primary tissue culture were investigated by morphometric and radioautographic methods. In such cells cAMP was found to induce: (1) a reduction of the apparent surface area (ASA) of total nucleoli, karyoplasm and cytoplasm; (2) significant increases in URC of all the subcellular compartments at all the dosages employed (only cAMP at 1.5-10-minus 8 M did not change karyoplasmic and cytoplasmic URC values); (3) marked increments in [Me--3H]Tdr L.I./h and M.I.% from the lowest dose up to 1.5-10-minus 4 M; at higher doses the L.I./h and M.I.% were less stimulated or approached control values. In cultured rat hepatocytes, adenosine-5'-phosphate (5'-AMP) (1.5-10-minus 4 M per 24 h) increased the karyoplasmic and total cell ASA, the lone total nucleolar URC and both the L.I./h and M.I.%. However, these metabolic effects were significantly less intense than those elicited by isomolar cAMP. Theophylline (Theo) (5.5-10-minus 5 M per 24 h) reduced the in vitro rat hepatocyte total nucleolar ASA but affected neither other morphometric nor any of the URC values. The same dose of Theo plus cAMP (1.5-10-minus M) had no morphometric effect but significantly increased the URC values of all primary rat hepatocyte compartments. Actinomycin D (DAct) (0.1 mug/ml per 24 h) plus cAMP (1.5-10-minus 4 M) decreased the cultured rat hepatocyte total nucleolar ASA but enlarged that of karyoplasm and cytoplasm and, further, markedly curtailed all the compartmental URC values. These data support the hypothesis that cAMP amplified the template activity of the liver chromatin and accelerates the flow of differentiated primary young rat hepatocytes into the various stages of the mitotic cell cycle.
采用形态计量学和放射自显影方法，研究了用不同剂量（从1.5×10⁻⁸至3.0×10⁻³M）的3',5'-环磷酸腺苷（cAMP）对原代组织培养的幼年大鼠分化肝细胞的形态计量学参数、[5-³H]尿苷放射性浓度（URC）、[甲基-³H]胸腺嘧啶核苷[Me-³H]-Tr）每小时标记指数（L.I./h）和有丝分裂指数百分比（M.I.%）的影响。在这些细胞中发现cAMP可诱导：（1）总核仁、核质和细胞质的表观表面积（ASA）减小；（2）在所采用的所有剂量下，所有亚细胞区室的URC均显著增加（仅1.5×10⁻⁸M的cAMP未改变核质和细胞质的URC值）；（3）从最低剂量到1.5×10⁻⁴M，[Me-³H]Tdr L.I./h和M.I.%显著增加；在更高剂量下，L.I./h和M.I.%受到的刺激较小或接近对照值。在培养的大鼠肝细胞中，腺苷-5'-磷酸（5'-AMP）（每24小时1.5×10⁻⁴M）增加了核质和细胞总ASA、单独的总核仁URC以及L.I./h和M.I.%。然而，这些代谢效应明显不如等摩尔cAMP引起的效应强烈。茶碱（Theo）（每24小时5.5×10⁻⁵M）降低了体外大鼠肝细胞总核仁ASA，但对其他形态计量学参数或任何URC值均无影响。相同剂量的Theo加cAMP（1.5×10⁻⁴M）没有形态计量学效应，但显著增加了原代大鼠肝细胞所有区室的URC值。放线菌素D（DAct）（每24小时0.1μg/ml）加cAMP（1.5×10⁻⁴M）降低了培养的大鼠肝细胞总核仁ASA，但扩大了核质和细胞质的ASA，并且进一步显著降低了所有区室的URC值。这些数据支持以下假设：cAMP增强了肝染色质的模板活性，并加速了分化的原代幼年大鼠肝细胞进入有丝分裂细胞周期的各个阶段。
