Peuhkuri K, Hukkanen M, Beale R, Polak J M, Vapaatalo H, Korpela R
Department of Pharmacology and Toxicology, University of Helsinki, Finland.
J Physiol Pharmacol. 1997 Dec;48(4):719-29.
The activity of lactase enzyme declines after weaning. This study was to investigate changes in the lactase expression in the whole gastrointestinal tract during the development and the possibility that this and activity can be induced by lactose. Expression of lactase protein in the gut of 1-12-weeks old rats was studied by immunocytochemistry. Possible induction was evaluated by immunohistochemical and biochemical techniques in 8-week-old rats after lactose challenge for seven days. Lactase immunoreactivity was detected only in the small intestine and it decreased 20% during the week after weaning. A steady level of 40% lower than in the sucklings was found in the adult rats. In the lactose-challenged rats the optical density of immunoreactivity increased by about 30% in those that consumed the highest concentration of lactose. In the proximal jejunum, elevation of the enzymatic activity was three-fold. In the rat lactase protein expression decreased rapidly after weaning and expression and activity were induced by lactose-rich diet, most notably in the proximal jejunum.
断奶后乳糖酶的活性会下降。本研究旨在调查发育过程中全胃肠道乳糖酶表达的变化，以及乳糖诱导这种表达和活性的可能性。通过免疫细胞化学研究1至12周龄大鼠肠道中乳糖酶蛋白的表达。通过免疫组织化学和生化技术评估8周龄大鼠在乳糖刺激7天后的可能诱导情况。仅在小肠中检测到乳糖酶免疫反应性，断奶后一周内其降低了20%。成年大鼠中发现其稳定水平比哺乳期大鼠低40%。在乳糖刺激的大鼠中，摄入最高浓度乳糖的大鼠免疫反应性光密度增加了约30%。在空肠近端，酶活性升高了三倍。在大鼠中，断奶后乳糖酶蛋白表达迅速下降，富含乳糖的饮食可诱导其表达和活性，最显著的是在空肠近端。
