Figure 1.

Longitudinal magnetic resonance imaging (MRI) analyses of prostatic enlargement in mice treated with combined testosterone (T) and estradiol (E). A: Schematic of experimental approach, whereby 10-week–old male C57BL6 mice were castrated and given a s.c. silastic implant containing either testosterone alone (T control) or a 10:1 ratio of testosterone and estradiol (T+E). At 8, 10, 12, and 15 weeks after castration, mice were imaged and tissues were obtained for histological analyses. B: Quantification of prostate volume by MRI demonstrates a significant increase in prostatic volume beginning at 12 weeks after treatment. C: Longitudinal analyses demonstrate an approximate doubling of prostatic volume in the T+E condition as compared to the T-control condition. The dotted lines represent a best-fit curve for each of the cohorts. D: Representative MR images illustrating changes in prostate volume as a function of time in mice treated with T+E. The prostate volume is indicated in color—a color bar is shown for the hyperintense prostate lesion on T2-weighted images; other anatomical sites (bladder and urethra) are also noted. The heat map correlates to fluid density, where red is more intense and blue is less intense. ^∗P < 0.05.