Abstract
The protein compositions of uterine secretions in young and aged hamsters during early pregnancy were studied by polyacrylamide slab-gel electrophoresis. Uterine luminal fluids were collected by flushing with a small amount of saline. A broad area of very rapidly migrating proteins, which was undetectable in plasma samples, appeared in the uterine fluids on Days 4 and 5 of pregnancy, which is when implantation occurs in this species. More protein bands were noted in this region in aged females in contrast to those of young females. Further, in the uterine fluids of aged hamsters, a post-albumin protein band disappeared at estrus and on Day 1 and the protein compositions in the post-transferrin region differed between the young and aged females. The qualitative changes in the protein content of the uterine fluids may account for the high rate of embryonic loss in aged hamsters.
