Klyde B J, Hirsch J
J Lipid Res. 1979 Aug;20(6):705-15.
The feeding of a high-fat diet to adult rats was shown to increase the incorporation of [3H]thymidine into DNA of the adipocyte and stromal fractions. After only 2 days on a high-fat diet there was a marked increase in the incorporation of label. When a 2-week period was interposed between [3H]thymidine administration and determination of DNA specific activity, the greatest increase in incorporation of label was found after 1 week on the diet, when incorporation increased 6-fold or more in both adipocytes and stroma and subsequently decreased to stabilize at a level two or three times that of chow-fed rats in the adipocyte fraction. Rats labeled when young and later placed on a high-fat diet showed a decrease in DNA specific activity in both adipocytes and stroma, confirming that cellular proliferation had occurred in both fractions. The specific activities of both stromal and adipocyte DNA were very similar at all time points studied. An attempt to increase the difference in specific activities by waiting many weeks after [3H]thymidine injection before isolating DNA was not successful. This may be because the total amount of DNA in the stromal and adipocyte fractions increases in parallel on the diet. The significance of these findings in terms of the normal turnover of adipose tissue DNA and the responsiveness to diet is discussed.
给成年大鼠喂食高脂饮食，结果显示可增加[3H]胸苷掺入脂肪细胞和基质部分DNA中的量。高脂饮食仅2天后，标记物的掺入就显著增加。当在给予[3H]胸苷与测定DNA比活性之间插入2周时间时，发现饮食1周后标记物掺入增加最多，此时脂肪细胞和基质中的掺入量均增加了6倍或更多，随后下降并稳定在脂肪细胞部分中以普通饲料喂养的大鼠的两到三倍水平。幼年时标记、后来改为高脂饮食的大鼠，其脂肪细胞和基质中的DNA比活性均降低，这证实了两个部分均发生了细胞增殖。在所研究的所有时间点，基质和脂肪细胞DNA的比活性都非常相似。在注射[3H]胸苷数周后再分离DNA以增加比活性差异的尝试未成功。这可能是因为饮食中基质和脂肪细胞部分的DNA总量平行增加。本文讨论了这些发现对于脂肪组织DNA正常更新以及对饮食反应性的意义。
