Biology of Reproduction, Vol 10, 543-548, Copyright © 1974 by Society for the Study of Reproduction

Ovum Implantation and Uterine Lysosomal Enzyme Activity

¹ Departments of Obstetrics and Gynecology and of Biological Chemistry, University of Cincinnati, College of Medicine, Cincinnati, Ohio 45229

Uterine cathepsin D activity (EC 3.4.4.b) and -glucuronidase activity (-D-glucoside glucohydrolase, EC 3.2.1.24) were determined in ovum implantation sites during early pregnancy. Within 24 h after implantation, cathepsin D activity decreased 50% at the implantation site; there was no change in -glucuronidase activity. Neither cathepsin D activity nor -glucuronidase activity increased during early pregnancy before the time of implantation. The presence of a thread in the uterine lumen had no effect on cathepsin D activity. In ovariectomized rats, both estradiol and progesterone increased cathepsin D activity, but estradiol was twice as effective in increasing the enzyme activity.