Identification and characterization of bovine oviductal glycoproteins synthesized at estrus

Published reports indicate that in several mammalian species the oviduct synthesizes and secretes specific glycoproteins which are components of the luminal fluids at the time of ovulation and fertilization. The present study characterized the secretory glycoproteins synthesized by the bovine oviduct at estrus. Oviducts obtained from four crossbred cows in estrus were flushed with saline, and segments of the ampullary and isthmic regions were fixed for immunocytochemical analyses. The remainder of the tissue was subjected to explant culture for 24 h in medium containing either 3H-leucine or 3H-glucosamine. Analysis of culture media by one- and two-dimensional SDS-PAGE followed by fluorography indicated that both the ampullary and isthmic regions synthesized a major class of Mr 97,000 glycoproteins with isoelectric points ranging from 5.5 to 8.1. A polyclonal antibody was generated to the glycoproteins after their isolation by gel filtration followed by electrophoretic separation. Western blot analysis of oviductal culture media indicated that the antisera cross-reacted with a doublet at Mr 97,000 and to a lesser extent with two additional bands at Mr greater than 200,000. Immunoreactive antigens were not identified in serum or in culture media of ovary, uterus, and nonreproductive tract tissues. The Mr 97,000 glycoproteins were present in oviductal flushings obtained from cows in estrus. They were also detected to a lesser degree in oviductal flushings obtained from cows at Days 5, 10, 15, and 18 of the estrous cycle, with the least amount of immunoreactivity being observed in Day 10 samples.(ABSTRACT TRUNCATED AT 250 WORDS)