Eppenberger-Eberhardt M, Messerli M, Eppenberger H M, Reinecke M
Institute of Cell Biology, ETH Hoenggerberg, Zürich, Switzerland.
J Mol Cell Cardiol. 1993 Jul;25(7):753-7. doi: 10.1006/jmcc.1993.1088.
Under normal physiological conditions atrial natriuretic factor (ANF) in rat is stored in secretory granules in fetal and adult atrial cardiomyocytes (Cantin et al., 1984; de Bold, 1985), whereas in fetal and neonatal ventricular cardiomyocytes secretory granules are practically absent and ANF is directly secreted via the constitutive pathway (Bloch et al., 1986; Cantin et al., 1987). In ventricular adult rat cardiomyocytes however, ANF is down-regulated and only expressed in cells of interventricular septum (Reinecke, 1989). These ANF-containing cells seem to constitute part of the Purkinje fibre system. As ventricular adult rat cardiomyocytes (ARC) in longterm culture in many ways re-express the fetal program (Eppenberger et al., 1988; Eppenberger-Eberhardt et al., 1990), it was of interest to investigate whether this was also the case for ANF. Data in the present study show that immunoreactive (IR) ANF is upregulated in cultured ventricular ARC and is stored just as in cultured atrial ARC in "atrial-type" granules and secreted into the medium. A possible analogy with overload heart hypertrophy in vivo, where a reactivation of an early gene program including re-expression of ANF in ventricular myocytes has been described (Izumo et al., 1987; Chien et al., 1991), is proposed.
在正常生理条件下，大鼠心房利钠因子（ANF）储存于胎儿和成年心房心肌细胞的分泌颗粒中（坎廷等人，1984年；德博尔德，1985年），而在胎儿和新生儿心室心肌细胞中，几乎不存在分泌颗粒，ANF通过组成型途径直接分泌（布洛赫等人，1986年；坎廷等人，1987年）。然而，在成年大鼠心室心肌细胞中，ANF表达下调，仅在室间隔细胞中表达（赖内克，1989年）。这些含ANF的细胞似乎构成了浦肯野纤维系统的一部分。由于成年大鼠心室心肌细胞（ARC）在长期培养中在许多方面重新表达胎儿程序（埃彭贝格尔等人，1988年；埃彭贝格尔 - 埃伯哈特等人，1990年），因此研究ANF是否也是如此很有意义。本研究数据表明，免疫反应性（IR）ANF在培养的心室ARC中上调，并像在培养的心房ARC中一样储存于“心房型”颗粒中，并分泌到培养基中。有人提出，这可能与体内超负荷心脏肥大类似，在体内已描述了包括心室肌细胞中ANF重新表达在内的早期基因程序的重新激活（出云等人，1987年；钱等人，1991年）。
