衰老会减少肝细胞因表皮生长因子（EGF）和肾上腺素而合成DNA的数量。
Aging reduces the numbers of hepatocytes synthesizing DNA in response to EGF and epinephrine.
作者信息
Kokkonen G C, Kitano S, Mock Y D, Ishigami A, Reed T D, Chrest F J, Roth G S
机构信息
Gerontology Research Center, National Institute of Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
出版信息
Exp Cell Res. 1997 Nov 25;237(1):77-82. doi: 10.1006/excr.1997.3763.
Primary cultures of hepatocytes were prepared from young (6 month) and old (24 month) Wistar rats and exposed to epinephrine or epidermal growth factor. Incorporation of [3H]thymidine into DNA was determined both radiochemically and autoradiographically. The numbers of responding cells and degree of response per cell were determined and the results confirmed by FACScan analysis. Such analyses clearly demonstrate a reduced number of hepatocytes capable of responding to the above stimuli in cultures obtained from old rats. Thus, changes in numbers of responding cells may be an important mechanism involved in reduced responsiveness of the aged liver to agents which stimulate DNA synthesis and cell division.
从幼年（6个月）和老年（24个月）Wistar大鼠中制备肝细胞原代培养物，并使其暴露于肾上腺素或表皮生长因子。通过放射化学和放射自显影法测定[3H]胸腺嘧啶核苷掺入DNA的情况。确定反应细胞的数量和每个细胞的反应程度，并通过流式细胞仪分析（FACScan analysis）对结果进行确认。此类分析清楚地表明，从老年大鼠获得的培养物中，能够对上述刺激产生反应的肝细胞数量减少。因此，反应细胞数量的变化可能是老年肝脏对刺激DNA合成和细胞分裂的物质反应性降低所涉及的一个重要机制。
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