Gene expression and functional abnormalities in XX/ Sry Leydig cells

The SRY gene induces testis development even in XX individuals. However, XX/ Sry testes fail to produce mature sperm, due to the absence of Y chromosome carrying genes essential for spermatogenesis. XX/ Sry Sertoli cells show abnormalities in the production of lactate and cholesterol required for germ cell development. Leydig cells are essential for male functions through testosterone production. However, whether XX/ Sry adult Leydig cells (XX/ Sry ALCs) function normally remains unclear. In this study, the transcriptomes from XY and XX/ Sry ALCs demonstrated that immediate early and cholesterogenic gene expressions differed between these cells. Interestingly, cholesterogenic genes were upregulated in XX/ Sry ALCs, although downregulated in XX/ Sry Sertoli cells. Among the steroidogenic enzymes, CYP17A1 mediates steroid 17α-hydroxylation and 17,20-lyase reaction, necessary for testosterone production. In XX/ Sry ALCs, the latter reaction was selectively decreased. The defects in XX/ Sry ALCs, together with those in the germ and Sertoli cells, might explain the infertility of XX/ Sry testes.