Tessitore L, Sesca E, Pani P, Dianzani M U
Dipartimento di Medicina ed Oncologia Sperimentale, Università degli Studi, Torino, Italy.
Chem Biol Interact. 1995 Jun 30;97(1):1-10. doi: 10.1016/0009-2797(94)03602-1.
A sexual dimorphism occurs in liver cell proliferation following partial hepatectomy, female liver regenerating faster than male, while a continuous excess of choline to females shifts their growth pattern toward that of males (L. Tessitore, P. Pani and M.U. Dianzani, Carcinogenesis, 13 (1992) 1929). In this study we have investigated (a) if the same sexual modulation occurs in a different type of liver growth, hyperplasia induced by a direct mitogen and (b) if the pre-administration of choline to females is able to modulate this dimorphism. Liver hyperplasia induced by lead nitrate, a potent mitogen, has also shown a peculiar sexual dimorphism in all phases of the proliferative process. In contrast with liver regeneration after partial hepatectomy, the mitogenic action of lead nitrate was less effective and was delayed in females as compared with males, by evaluating liver weight, protein accumulation, DNA synthesis and mitotic index. These results were also confirmed by the trend of liver regression by apoptosis. The apoptotic index was higher in males than in females. A prolonged administration of an excess of choline has partially filled these sexual differences, since choline has moved, in females, all the observed parameters (liver weight, protein accumulation, DNA synthesis, mitotic and apoptotic indexes) to values closer to those observed in males.
部分肝切除术后肝细胞增殖存在性别二态性，雌性肝脏比雄性肝脏再生得更快，而持续给予雌性过量胆碱会使其生长模式向雄性转变（L. 泰西托雷、P. 帕尼和M.U. 迪亚扎尼，《癌变》，13 (1992) 1929）。在本研究中，我们调查了：(a) 在由直接有丝分裂原诱导的不同类型的肝脏生长即增生中，是否发生相同的性别调节；(b) 预先给予雌性胆碱是否能够调节这种二态性。由强效有丝分裂原硝酸铅诱导的肝脏增生在增殖过程的所有阶段也表现出一种特殊的性别二态性。与部分肝切除术后的肝脏再生相反，通过评估肝脏重量、蛋白质积累、DNA合成和有丝分裂指数，硝酸铅的有丝分裂作用在雌性中比在雄性中效果更差且延迟。这些结果也通过凋亡导致的肝脏消退趋势得到证实。雄性的凋亡指数高于雌性。长期给予过量胆碱部分弥补了这些性别差异，因为胆碱使雌性的所有观察参数（肝脏重量、蛋白质积累、DNA合成、有丝分裂和凋亡指数）更接近在雄性中观察到的值。
