Metabolism of adrenal androgen and its impacts on prostate cancer after castration:

Castration causes an increase in lysosomal size and upregulation of cathepsin D expression in principal cells along with increased secretion of procathepsin D and prosaposin oligomers in adult rat epididymis

In the epididymis, lysosomal proteins of the epithelial cells are normally targeted from the Golgi apparatus to lysosomes for degradation, although their secretion into the epididymal lumen has been documented and associated with sperm maturation. In this study, cathepsin D (CatD) and prosaposin (PSAP) were examined in adult epididymis of control, and 2-day castrated rats without (Ct) and with testosterone replacement (Ct+T) to evaluate their expression and regulation within epididymal epithelial cells. By light microscope-immunocytochemistry, a quantitative increase in size of lysosomes in principal cells of Ct animals was noted from the distal initial segment to the proximal cauda. Androgen replacement did not restore the size of lysosomes to control levels. Western blot analysis revealed a significant increase in CatD expression in the epididymis of Ct animals, which suggested an upregulation of its expression in principal cells; androgens restored levels of CatD to that of controls. In contrast, PSAP expression in Ct animals was not altered from controls. Additionally, an increase in procathepsin D levels was noted from samples of the epididymal fluid of Ct compared to control animals, accompanied by an increased complex formation with PSAP. Moreover, an increased oligomerization of prosaposin was observed in the epididymal lumen of Ct rats, with changes reverted to controls in Ct+T animals. Taken together these data suggest castration causes an increased uptake of substrates that are acted upon by CatD in lysosomes of principal cells and in the lumen by procathepsin D. These substrates may be derived from apoptotic cells noted in the lumen of proximal regions and possibly by degenerating sperm in distal regions of the epididymis of Ct animals. Exploring the mechanisms by which lysosomal enzymes are synthesized and secreted by the epididymis may help resolve some of the issues originating from epididymal dysfunctions with relevance to sperm maturation.

The effects of storage time and sampling season on the stability of serum 25-hydroxy vitamin D and androstenedione

Knowledge of the stability of serum samples stored in large biobanks is pivotal for reliable assessment of hormone-dependent disease risks. We studied the effects of sample storage time and season of serum sampling on the stability of 25-hydroxy vitamin D (25-OHD) and androstenedione in a stratified random sample of 402 women, using paired sera from the Finnish Maternity Cohort. Serum samples selected were donated between 6 and 24 yr ago. The storage time did not affect serum 25-OHD and androstenedione levels. However, there was a significant mean difference in the 25-OHD levels of sera withdrawn during winter (first sample) vs. during summer (second sample; -18.4 nmol/l, P <or= 0.001). Also at the individual level, there were significant differences in average 25-OHD levels between individuals with the paired sera taken at winter-winter compared with other alternatives (summer-winter, winter-summer, and summer-summer). The androstenedione levels showed no such differences. Long-term storage does not affect serum 25-OHD and androstenedione levels, but sampling season is an important determinant of 25-OHD levels. Stored serum samples can be used to study disease associations with both hormones. However, sampling season needs to be taken into account for 25-OHD by considering matching and stratification and, if possible, serial sampling.