Potier M, Guay P, Lamothe P, Bousquet D, Dallaire L, Melançon S B
J Reprod Fertil. 1979 Sep;57(1):49-57. doi: 10.1530/jrf.0.0570049.
Intestinal lactase activity (with its associated cellobiase, 4-methylumbelliferyl-beta-galactosidase and -beta-glucosidase activities) was used as a specific intestinal marker enzyme to study the release of protein and enzymes of intestinal origin in sheep amniotic fluid during gestation. In amniotic fluid, intestinal lactase activity peaked at 66--85 days of gestation and then decreased with gestation. This enzyme activity was very low or absent in allantoic fluid throughout gestation suggesting that there is no important transfer of amniotic fluid lactase towards the allantoic cavity. Maltase and 4-methylumbelliferyl-alpha-glucosidase showed no statistically significant variation with gestation in both amniotic and allantoic fluid whereas alpha-galactosidase and N-acetyl-beta-hexosaminidase which were first higher in allantoic than in amniotic fluid increased in amniotic fluid to reach allantoic fluid levels near term. Such patterns are consistent with the suggestion that the fetal urine is a source of alpha-galactosidase and N-acety-beta-hexosaminidase activities and that sheep urine is first accumulated in the allantoic sac via the urachus up to 86--90 days of gestation and thereafter passes more and more into the amniotic sac.
肠道乳糖酶活性（及其相关的纤维二糖酶、4-甲基伞形酮基-β-半乳糖苷酶和-β-葡萄糖苷酶活性）被用作一种特定的肠道标记酶，以研究妊娠期间绵羊羊水内肠道源性蛋白质和酶的释放情况。在羊水中，肠道乳糖酶活性在妊娠66 - 85天时达到峰值，随后随妊娠进程而下降。在整个妊娠期间，尿囊中该酶活性非常低或不存在，这表明羊水中的乳糖酶没有大量转移至尿囊腔。麦芽糖酶和4-甲基伞形酮基-α-葡萄糖苷酶在羊水和尿囊液中均未显示出随妊娠有统计学意义的变化，而最初尿囊液中高于羊水的α-半乳糖苷酶和N-乙酰-β-己糖胺酶在羊水临近足月时升高至与尿囊液水平相当。这些模式与以下观点一致：即胎儿尿液是α-半乳糖苷酶和N-乙酰-β-己糖胺酶活性的来源，并且绵羊尿液在妊娠86 - 90天之前首先通过脐尿管积聚在尿囊中，此后越来越多地进入羊膜囊。
