IMMUNOLOCALIZATION OF ACIDIC AND BASIC FIBROBLAST GROWTH-FACTORS IN PORCINE UTERINE AND CONCEPTUS TISSUES

Immunohistochemical techniques were used to localize acidic and basic fibroblast growth factor (FGF) polypeptides in porcine uterine and con ceptus tissues collected on Days 10 through 14 of gestation, which is the peri-implantation period, and in uterine tissues collected on the same days of the estrous cycle. Our results demonstrate differential e xpression of acidic and basic FGF (aFGF, bFGF) in porcine uterine and conceptus tissues. Localization of these peptides in the uterus of cyc ling and pregnant pigs was different from that reported for other spec ies, suggesting species-specific roles for FGFs in early pregnancy. In creases in both cytoplasmic and nuclear bFGF immunostaining were detec ted in uterine luminal and glandular epithelial cells from Days 10 to 14 of gestation but not in the uterine epithelium of cycling pigs. Aci dic FGF immunostaining was not detected in luminal or glandular epithe lium of either cycling or pregnant uterine tissue; however, differenti al stromal staining was observed. Uterine tissues collected from pigs on Days 10-14 of the estrous cycle had diffuse aFGF immunostaining thr oughout the stroma. During early pregnancy, however, intense aFGF immu nostaining was concentrated around the glandular epithelial and below the luminal epithelial cells as gestation progressed. Basic FGF, but n ot aFGF, was detected in porcine conceptuses collected during the peri -implantation period (Days 10-14 of gestation). Although both acidic a nd basic FGF belong to the same family of proteins, results of the pre sent study indicate that they likely play different roles in uterine f unction and conceptus development in pigs.