Buts J P, De Meyer R, Kolanowski J
Am J Physiol. 1983 May;244(5):G469-74. doi: 10.1152/ajpgi.1983.244.5.G469.
This study was undertaken to determine whether the rat colon exhibits ontogenic changes in epithelial cell proliferation and DNA synthesis during growth. DNA synthesis was measured at intervals after birth in four colonic segments by the incorporation rates of [3H]thymidine. The labeled crypt cell index was determined by radioautography. New findings from our study are that 1) in each colonic segment of suckling rats, [3H]thymidine incorporation rate overshot the adult levels (49-119%) with a peak occurring at day 14 postpartum, 2) between days 14 and 20, the incorporation rates declined sharply to adult values and remained thereafter unchanged until adulthood; during the same period, the labeled and mitotic index decreased, respectively, from 52 to 19% and from 3.58 to 1.43%, 3) the decrease in DNA synthesis and in cell proliferation rates was concomitant with an upsurge in plasma total corticosterone initiated on day 14, and 4) treatment of 10-day-old sucklings with physiological doses of hydrocortisone for 4 consecutive days significantly depressed (P less than 0.01) colonic DNA content and DNA synthesis rates to levels about 45-67% of the control values. These data indicate that growth of the colon may be under the control of glucocorticoid secretion at the weaning period.
本研究旨在确定大鼠结肠在生长过程中上皮细胞增殖和DNA合成是否呈现个体发生变化。通过[3H]胸腺嘧啶核苷的掺入率，在出生后的不同时间间隔测量四个结肠段的DNA合成。通过放射自显影法测定标记的隐窝细胞指数。我们研究的新发现是：1）在乳鼠的每个结肠段中，[3H]胸腺嘧啶核苷掺入率超过成年水平（49 - 119%），在产后第14天出现峰值；2）在第14天至第20天之间，掺入率急剧下降至成年值，此后直至成年保持不变；在同一时期，标记指数和有丝分裂指数分别从52%降至19%，从3.58%降至1.43%；3）DNA合成和细胞增殖率的下降与第14天开始的血浆总皮质酮激增同时发生；4）用生理剂量的氢化可的松连续4天治疗10日龄乳鼠，显著降低（P小于0.01）结肠DNA含量和DNA合成率，降至对照值的约45 - 67%。这些数据表明，结肠的生长可能在断奶期受糖皮质激素分泌的控制。
