Oestrogen receptor localization in the testis. The Figure summarises up-to-date information on the localization of ERα, ERβ and GPER in human, pig, rat and mouse testicular cells. * Elderly men (60–80 years old) undergoing surgery due to prostatic cancer; ** azoospermia, maturation arrest, Sertoli cell-only; *** azoospermia, vasectomy; **** azoospermia, patients undergoing vasectomy; ¤ positive or negative ERα detection in spermatogonia depending on the approach used: IHC—positive staining with HC-20 antibody, negative staining with F-10 antibody, ISH—positive; † rat; †† mouse; ††† human; IHC—Immuno Histo Chemistry; ISH—In Situ Hybridization; qRT-PCR—quantitative Reverse Transcription Polymerase Chain Reaction; WB—Western Blot detection; scbt—Santa Cruz Biotechnology.