Lev R, Bender M S, Appleton H D
Histochemistry. 1979 Jul 11;61(3):255-62. doi: 10.1007/BF00508446.
A single dose of 20 mg beta-D-lactose injected into the amniotic sac of rats on day 17 of pregnancy induced an increase in lactase activity in fetal jejunum. This effect was first noted two days after injection and lasted for at least two additional days. Histoenzymatic investigation indicated that this enzyme was located on the surface of the absorptive cells lining the villi and thus corresponds to the "dietary" form of beta-galactosidase. A much smaller increase, based presumably on progressive increase in fetal size (age) was found in control fetuses which had received glucose or no injections. Peak lactase values in fetuses receiving lactose were substantially higher than peak values in control fetuses. In both lactose-injected and non-injected rats which were allowed to deliver, there was a sharp drop in lactase values coincident with birth.
在妊娠第17天向大鼠羊膜腔内注射20毫克β-D-乳糖的单次剂量，可使胎儿空肠中的乳糖酶活性增加。这种效应在注射后两天首次被注意到，并至少持续另外两天。组织酶学研究表明，这种酶位于绒毛内衬吸收细胞的表面，因此与β-半乳糖苷酶的“饮食”形式相对应。在接受葡萄糖或未注射的对照胎儿中，发现了基于胎儿大小（年龄）逐渐增加的小得多的增加。接受乳糖的胎儿中的乳糖酶峰值明显高于对照胎儿中的峰值。在允许分娩的注射乳糖和未注射乳糖的大鼠中，乳糖酶值均随着出生而急剧下降。
