Majumdar A P, Johnson L R
Am J Physiol. 1982 Feb;242(2):G135-9. doi: 10.1152/ajpgi.1982.242.2.G135.
Changes in cell proliferation and cell loss in the gastric mucosa were examined during the first 4 wk of life. The effect of pentagastrin on these parameters before and after weaning was also investigated. The results revealed that DNA content of mucosa and lumen increased with age. However, when luminal DNA (an assessment of cell loss) content was expressed as percent of total mucosal DNA (referred to as percent cell loss), an inverse relationship with age was observed. The rate of mucosal DNA synthesis, measured in vitro, was found to remain elevated up to the age of 15 days and then dropped dramatically within the next 5--6 days after which it decreased slowly. The rate of mucosal DNA synthesis in 5- to 15-day-old rats was found to be 10--15 times higher than in 20- to 30-day-old rats. In 10-day-old suckling young, mucosal thymidine kinase activity was also found to be higher than in 20- to 28-day-old rats. On the other hand, total incorporation of [3H]thymidine into mucosal DNA per stomach was found to be significantly greater in 21- to 28-day-old weaned rats than in the 10-day-old suckling young. Multiple injections of pentagastrin to 28-day-old rats significantly increased mucosal DNA synthesis and thymidine kinase activity by 43 and 200%, respectively, and cell loss by 30% when compared with the saline control. The hormone did not affect DNA synthesis, thymidine kinase, or cell loss in 10-day-old rats. There were considerable increases in 20-day-old rats that were not statistically significant due to the variation of the data.
在出生后的前4周内，对胃黏膜中细胞增殖和细胞丢失的变化进行了检查。还研究了五肽胃泌素在断奶前后对这些参数的影响。结果显示，黏膜和管腔的DNA含量随年龄增长而增加。然而，当管腔DNA（细胞丢失的一种评估指标）含量以总黏膜DNA的百分比表示（称为细胞丢失百分比）时，观察到其与年龄呈负相关。体外测量的黏膜DNA合成速率在15日龄前一直保持升高，然后在接下来的5 - 6天内急剧下降，之后缓慢降低。发现5至15日龄大鼠的黏膜DNA合成速率比20至30日龄大鼠高10 - 15倍。在10日龄的哺乳幼鼠中，还发现黏膜胸苷激酶活性高于20至28日龄大鼠。另一方面，发现21至28日龄断奶大鼠每只胃黏膜DNA中[3H]胸苷的总掺入量明显高于10日龄的哺乳幼鼠。与生理盐水对照组相比，对28日龄大鼠多次注射五肽胃泌素可使黏膜DNA合成和胸苷激酶活性分别显著增加43%和200%，细胞丢失增加30%。该激素对10日龄大鼠的DNA合成、胸苷激酶或细胞丢失没有影响。20日龄大鼠有相当程度的增加，但由于数据的变化，在统计学上不显著。
