Lee M F, Russell R M, Montgomery R K, Krasinski S D
Jean Mayer USDA-Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
J Nutr. 1997 Jul;127(7):1382-7. doi: 10.1093/jn/127.7.1382.
Lactase-phlorizin hydrolase (LPH) and sucrase-isomaltase (SI) are intestinal microvillus membrane hydrolases that play important roles in carbohydrate digestion. Although the expression of these enzymes during postnatal development has been characterized, the effect of old age on disaccharidase activity is poorly understood. In the present investigation, we examined the effect of aging on lactase and sucrase activities and their mRNA levels in the small intestines of 3-, 12- and 24- mo-old rats by sampling from nine equidistant segments of small intestine. Total intestinal disaccharidase activity or mRNA abundance was determined from areas under the proximal-to-distal curves. Rats 24 mo of age had total intestinal lactase and sucrase activities that were 12 and 38% lower, respectively, than the 3-mo-old animals (P < 0.05). In contrast, total LPH and SI mRNA abundance did not change significantly. Thus, total intestinal lactase and sucrase activities decrease with age in a manner that likely involves a posttranscriptional process. The age-related decline in disaccharidase activity, if extrapolated to humans, may have important implications for the digestion of carbohydrate contained in the diet of the elderly.
乳糖酶-根皮苷水解酶（LPH）和蔗糖酶-异麦芽糖酶（SI）是肠道微绒毛膜水解酶，在碳水化合物消化中起重要作用。尽管这些酶在出生后发育过程中的表达已得到表征，但衰老对双糖酶活性的影响却知之甚少。在本研究中，我们通过从小肠的九个等距段取样，研究了衰老对3、12和24月龄大鼠小肠中乳糖酶和蔗糖酶活性及其mRNA水平的影响。从近端到远端曲线下的面积确定总肠道双糖酶活性或mRNA丰度。24月龄大鼠的总肠道乳糖酶和蔗糖酶活性分别比3月龄动物低12%和38%（P<0.05）。相比之下，总LPH和SI mRNA丰度没有显著变化。因此，总肠道乳糖酶和蔗糖酶活性随年龄增长而下降，这可能涉及转录后过程。如果将双糖酶活性与年龄相关的下降外推至人类，可能对老年人饮食中碳水化合物的消化具有重要意义。
