Henning S J, Helman T A, Kretchmer N
Biol Neonate. 1975;26(3-4):249-62. doi: 10.1159/000240736.
Some of the cellular and molecular events involved in the normal and precocious appearance of sucrase in jejunum of infant rats have been studied. Actinomycin D has been shown to inhibit (by 79%) the rise in sucrase activity usually seen after administration of hydrocortisone to 9-day-old rats. The precocious appearance of sucrase has also been studied with respect to the cytological localization of enzyme activity in the intestinal mucosa. Tissue was sectioned in a cryostat (transverse to the villi) and sucrase was assayed in homogenates prepared from the sections. By 24 h after administration of hydrocortisone to 9-day-old animals, sucrase was detectable only at the bases of the villi. During the subsequent 72 h the enzyme activity increased and spread along the villi at a rate consistent with that of cell migration. These data have lead to the conclusion that the action of glucocorticoids on enterocytes can occur only when the cells are in their proliferative phase. An ontogenic study of the ability of hydrocortisone to elicit jejunal sucrase showed that the tissue becomes increasingly responsive to the hormone with increasing age through the first and second postnatal weeks. Various hypotheses to explain this increase have been examined.
对幼鼠空肠中蔗糖酶正常和早熟出现所涉及的一些细胞和分子事件进行了研究。已证明放线菌素D能抑制（79%）通常在给9日龄大鼠注射氢化可的松后出现的蔗糖酶活性升高。还就蔗糖酶在肠黏膜中的酶活性细胞定位对其早熟出现进行了研究。将组织在低温恒温器中切片（与绒毛垂直），并对从切片制备的匀浆进行蔗糖酶测定。在给9日龄动物注射氢化可的松后24小时，仅在绒毛底部可检测到蔗糖酶。在随后的72小时内，酶活性增加并以与细胞迁移一致的速度沿绒毛扩散。这些数据得出结论，糖皮质激素对肠上皮细胞的作用仅在细胞处于增殖期时才会发生。对氢化可的松引发空肠蔗糖酶能力的个体发育研究表明，在出生后的第一周和第二周，组织对该激素的反应性随年龄增长而增强。已经检验了各种解释这种增加的假说。
