17beta-HSD8 belongs to the 17beta-HSD family of proteins that regulate the availability of steroids within a tissue. 17beta-HSD8 converts active steroids to their inactive form through its oxidative activity. It is a key player in the inactivation of Estradiol and Testosterone. 17beta-HSD8 is predominantly expressed in placenta, endometrium and prostate but can also be found in liver, and pancreas, with lowest levels found in testis, ovary and kidney. It has been proposed that a reduction in the levels of 17beta-HSD8 may lead to abnormal elevations in the local level of sex steroids, which can lead to recessive renal cystic disease. It has also been suggested that low levels of 17beta-HSD proteins may result in an underdeveloped urogenital system.