We previously had not noted CRABP expression in the stromal cells of normal cycling rats, but in those studies the uteri were examined only in cross section. In order to determine whether the temporal and region-dependent expression of CRABP in the stromal cells was unique to the pregnant uterus, we prepared new sections of the normal cycling uterus, now cut longitudinally. We observed that some of the stromal cells on the mesometrial side stained positively for CRABP, but only during the estrous stage (Fig. 3F). Further, cells that were positive for CRABP were considerably fewer in number than for the Day 1 pregnant uterus. The staining was found to have the same regional dependence described above. The cross sections stained for the estrous state in our previous study came from the middle region. ventolin inhalers

Cell-Specific Localization of CRABP(II)

In the normal estrous cycle, CRABP(II) is found to be highly expressed in the luminal epithelial cells, but only during estrus; only faint staining was noted the day after estrus. Here strong staining for CRABP(II) was observed for the luminal epithelium at Day 1 of pregnancy, 1 day after estrus. The intensity of CRABP(II) staining was also noted to be stronger on the mesometrial side than on the antimesometrial side. This was observed only on Day 1 (Fig. 4, A and B). Visible, but much less significant, staining was detected after Day 1. On Day 4 and Day 5, there was an increased staining for CRABP(II) in the luminal epithelium; also a visible, but weaker, staining appeared in the glandular epithelium (Fig. 4, C-E). These results correlated well with the estimation of CRABP(II) expression by Western blot (Fig. 1) and also matched the pattern seen for CRBP at these sites. Immunoreaction for CRABP(II) was then observed in the primary decidual cells around the implantation chamber on Day 6 and Day 7 (Fig. 4, F-H). On Day 7, some staining was also noted in the secondary decidual cells on the antimesometrial side, but much less than seen on the other side (Fig. 4, G and H).
Fig4Spatial and temporal patterns
FIG. 4. Immunohistochemical localization of CRABP(II) in the rat uterus during the periimplantation period. The affinity-purified IgG fraction that recognizes CRABP(II) (see Fig. 1) was used for analysis of the expression of CRABP(II) in the uterus. A) Longitudinal section showing the antimesometrial side of the uterus at Day 1. Light staining of the epithelium can be seen (filled arrowhead). Inset) Higher-power view of the antimesometrial side.