Fos plays no role in apoptosis of epithelia in the mouse male accessory sex organs and uterus

Roles of Fos in apoptosis of epithelia in the mouse male accessory sex organs and uterus were investigated using Fos-deficient mice. Normal 30- and 50-day-old and Fos-deficient 50-day-old male and female mice were castrated, and testosterone propionate and estradiol-17 beta were daily injected into male and female mice, respectively, for 5 days. An apoptotic index (a percentage of apoptotic cells) in the epithelium was examined from the day following the last injection (day 1) to day 8. The body weights and the weights of the ventral prostate (VP), coagulating gland (C), seminal vesicle (SV) and epididymis (Ep) and uterus of 50-day-castrated Fos-deficient mice on day 1 suggested that the development of these mice corresponded to that of 30-day-castrated normal mice at the most. The extents of apoptosis estimated by an apoptotic index in the VP, C, SV, Ep and uterus in 50-day-castrated Fos-deficient mice were comparable to those in 30-day-castrated normal mice. The extents of apoptosis in the SV, Ep and uterus in 30-day-castrated normal and 50-day-castrated Fos-deficient mice were similar to those in 50-day-castrated normal mice, while the extents of apoptosis in the VP and C in the former two groups of mice were less than those in the latter mice. The present results show that Fos-deficiency does not affect apoptosis in the SV, EP and uterus. However, the extents of apoptosis in the VP and C were less in 50-day-castrated Fos-deficient mice than in 50-day-castrated normal mice. This seems to be due to the retarded development of 50-day-castrated Fos-deficient mice, but not to a role of Fos in apoptosis.