MFN1 and hypogonadism: Moreover, hypogonadism was found to affect mitofusin (Mfn1) and mitofusin (Mfn2) in the Leydig cells by reducing the transcription of Drp1, as well as Mfn1 and Mfn2, without changing protein optic atrophy 1 (Opa1) levels [23].