Morphometric data on profile area measurements in the epithelium, lumen and tubule obtained from the testis, efferent ducts and epididymis of WT (Cst8+/+) and KO (Cst8−/−) mice at 4 and 10–12 months of age. Tubular, epithelial and luminal areas were collected from eighty (testis) or forty (epididymis) tubules in each subgroup of the data set. A) Seminiferous epithelium of the testis from mice aged 10–12 months; B) Stage specificity of the seminiferous epithelium from mice aged 10–12 months; C) Efferent ducts; D) Proximal initial segment; E) Distal initial segment; F) Caput. Circles (Tarea) indicate tubule profile area, diamonds (Earea) indicate epithelial profile area, and squares (Larea) indicate luminal profile area. Asterisks indicate difference of means that are significant (p < 0.05). The most profound changes are seen in the proximal initial segment of the epididymis of older mice (d).