Expressional Modulation of Aquaporin 1 and 9 in the Rat Epididymis by an Anabolic-Androgenic Steroid, Nandrolone Decanoate.

The spermatozoa become mature in the epididymis which is divided into initial segment and caput, corpus, and cauda epididymis. The water movement across the epididymal epithelium is important for creating luminal microenvironment for sperm maturation. Aquaporins (s) are water channel proteins, and expression of s is regulated by androgens. The current research was focused to examine expressional regulation of and by an androgenic-anabolic steroid, nandrolone decanoate (ND). The ND at the low dose (2 mg/ kg body weight/week) or high dose (10 mg) was subcutaneously administrated into male rats for 2 or 12 weeks. Transcript levels of and were determined by quantitative real-time polymerase chain reaction (PCR) analyses. In the initial segment, level of was decreased with 12 week-treatment, while level was decreased by the high dose treatment for 12 weeks. In the caput epididymis, expression was decreased by the low dose treatment. The 2 week-treatment resulted in an increase of level but a decrease of expression in the corpus epididymis. In the corpus epididymis, the 12 week-treatment at the low dose caused the reduction of and levels, but the high dose treatment resulted in an increase of expression and a decrease of level. In the cauda epididymis, expression was decreased by 2 and 12 week-treatments, while increases of levels was detected with the high dose treatment for 2 weeks and with 12 week-treatment. These findings indicate differential regulation of and expression among epididymal segments by ND.