PLOD1 and Azoospermia: A recent study has demonstrated the elevated expression of cytochrome P450 aromatase, which catalyzes the conversion of testosterone to estradiol in Leydig cells of men with nonobstructive azoospermia, and elevated circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which induce aromatase expression (Shiraishi et al., 2021).