Temporal Changes in Proteins of Oviduct and Uterine Fluids During the Preimplantation Period in the Rabbit

Abstract

At various times during the 1st 6 days of pregnancy, the lumen of the oviducts and uteri of normally mated and superovulated does were flushed with saline, and the polypeptides present in these flushings were separated in a 2-dimensional (isoelectric focusing, sodium dodecyl sulfate) electrophoresis system. Information was obtained regarding similarities and differences in polypeptide patterns between the stages and between the tissues. The major protein in the oviduct is albumin, but in the uterus at later preimplantation stages it is uteroglobin. During the preimplantation period the polypeptide environment in the oviduct remains virtually the same, while in the uterus there is a disappearance of albumin and a marked increase in uteroglobin. Immunoelectrophoresis demonstrated that of the more than 50 polypeptides resolved in 2-dimensional electrophoresis of oviduct fluid, at least 5 are identical to serum proteins (albumin, Ig[immunoglobulin]G, transferrin and possibly haptoglobin and .alpha.-2-macroglobulin). Uterine fluid at day 1 to 2 postcoitum (p.c.) also contains these 5 serum proteins. By day 3 p.c., the uterine fluid contains little protein which reacts with antisera directed toward rabbit serum proteins. Some differences were noted in polypeptide patterns of uterine flushes during early preimplantation stages of superovulated does vs. those from normal matings. Comparable differences were not observed in oviduct fluids.