大鼠小肠乳糖酶活性的发育模式以及乳糖、氢化可的松和胰岛素的影响

DEVELOPMENTAL PATTERN OF LACTASE ACTIVITY OF THE SMALL INTESTINE IN RATS AND THE EFFECTS OF LACTOSE, HYDROCORTISONE AS WELL AS INSULIN ON IT

不同鼠龄大鼠173只用于观察发育过程中小肠乳糖酶活性的变化,同时测定蔗糖酶及碱性磷酸酶活性。另用60只小鼠研究乳糖、氢化可的松及胰岛素对酶活性发育的影响。结果表明:出生前胎鼠小肠中乳糖酶活性已开始增加,出生后前三周空、回肠酶活性均处于很高水平,以后二者迅速下降至成年低水平。相反,蔗糖酶及碱性磷酸酶在成年期均具有高活性。发育过程中给动物胃饲乳糖、注射氢化可的松或胰岛素均使小肠乳糖酶活性下降速度变慢,但不能阻止其下降。

173 rats of different ages were used to observe the changes of lactase activity of small intestine during development. Sucrase and alkaline phosphatse activities were also measured. Another 60 rats were used in order to study the effects of lactose, hydrocortisons and insulin. Our results indicate that lactase activity of the small intestion of fetal rat begins to rise from prenatal period. The lartasc activity sustains a very high level both in jejunum and ileum during tue first 3 weeks of postnatal development, then both decline rapidly to very low adult values. On the contrary, sucrase and alkaline phosphatase activities are high throu-ght the whole adult life.Gastric feeding of lactose and injection of hydrocortisone or insulin reduce the rate of declination of lactase activity, but do not prevent its dropping. All of these facts reveal that lartase deficiency of adult small intestine is the normal result of developmental maturation of this enzyme in mammalian rat