Weights of individual corpora lutea were as follows: corpora lutea of the current cycle (proestrus) averaged 1.10 ± 0.09 mg (n = 8 rats), versus 0.87 ± 0.02 mg (n = 5 rats) for regressing corpora lutea from the previous cycle (estrus morning) and 0.75 ± 0.04 mg (n = 5 rats) for estrus afternoon (p < 0.05, proestrus vs. morning of estrus; p < 0.05, proestrus vs. afternoon of estrus). flovent inhaler
Monocytes/macrophages (ED1-positive) and differentiated macrophages (ED2-positive) were detected by immu-nohistochemistry in sections of isolated corpora lutea of the current cycle from rats killed on the morning of proestrus (n = 7) and in sections of isolated regressing corpora lutea from the previous cycle from rats killed on the afternoon of estrus (n = 7). Mean ± SEM numbers of luteal monocytes/macrophages per high-power field were, respectively, 1.4 ± 0.5 and 9.4 ± 0.9 (p < 0.001; Fig. 4). Numbers of differentiated macrophages per high-power field were, respectively, 1.1 ± 0.2 and 6.6 ± 1.6 (p < 0.05; Fig. 4).
Mean ± SEM numbers of apoptotic nuclei per high-power field were respectively, 1.3 ± 0.2 and 4.7 ± 0.5 (p < 0.001; Fig. 5). Visually, the cells that appeared to be undergoing apoptosis were large round cells typical of the steroidogenic luteal cells. Total number of cell nuclei per high-power field was also determined as an indicator of whether cell shrinkage and tissue compression were taking place. This number was not significantly different between proestrus and the afternoon of estrus (260.3 ± 16 vs. 230.3 ± 16.5, respectively; p > 0.05).
FIG. 4. Numbers of luteal ED1 + cells and ED2+ cells per high-power field in sections of isolated corpora lutea from rats killed on proestrus and estrus PM (experiment 2). One asterisk indicates a significant difference at p < 0.05, while three asterisks indicate a significant difference at p < 0.001.