Effects of Parity and Serum Prolactin Levels on the Incidence and Regression of DMBA-Induced Tumors in OFA hr/hr Rats

Figure 2

Hyperprolactinemia or pregnancy and lactation modify the ratio parenchyma/stroma in the mammary gland. Representative microphotographs (100x) of H&E-stained normal mammary tissue from nulliparous rats ((a) and (b)), hyperprolactinemic rats ((c) and (d)), and primiparous rats ((e) and (f)), with development ((a), (c), and (e)), or absence ((b), (d), and (f)) of mammary tumors. (g) Quantifications of the relative percentages of the alveolar area. Values represent mean ± S.E.M. of 8–10 fields of each preparation from 11–26 animals per group. ^∗∗𝑃<0.001, ^∗∗∗𝑃<0.0001 comparing the selected groups. Comparisons were performed by ANOVA I. Arrows show alveolar structures.

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