Lanosterol 14 alpha-demethylase (CYP51) and spermatogenesis

CYP51. is the only gene of the cytochrome P450 (P450, or CYP) superfamily t hat is expressed in prokaryotes and eukaryotes. In animals, the gene produc t, P45014DM, catalyzes the lanosterol 14 alpha-demethylase reaction, an ess ential step in cholesterol biosynthesis. P45014DM serves a housekeeping rol e, and it was surprising to find the highest level of CYP51 expression in t he testes. This is a result of very high-level CYP51 expression in postmeio tic, haploid spermatids and results in elevated P45014DM activity in these cells. It is proposed that the elevated level of 14 alpha-demethylase activ ity leads to production of signaling sterols by haploid germ cells, althoug h the function of such sterols in males is unknown.