摘要Background Follicle stimulating hormone is necessary for normal reproduction in men.The biochemical actions of follicle stimulating hormone result from binding to the follicle stimulating hormone receptor in the plasma membrane of Sertoli cells.Here,we investigated the expression of the follicle stimulating hormone receptor in different testicular histological phenotypes of patients with idiopathic azoospermia.Methods Fifty-seven cases of idiopathic azoospermia were classified into three groups according to the results of testicular biopsy:patients with hypospermatogenesis,patients with maturation arrest,and patients with Sertoli cell-only syndrome.Thirteen azoospermic patients identified by testicular biopsy as being capable of completing spermatogenesis acted as the control group.Immunohistochemistry and real-time quantitative reverse-transcriptase polymerase chain reaction were performed in each case,and the serum hormone level was also measured in all patients.Results The serum follicle stimulating hormone level in patients with Sertoli cell-only syndrome was significantly higher than in patients with hypospermatogenesis,maturation arrest,and complete spermatogenesis (P＜0.01).The serum follicle stimulating hormone level in patients with maturation arrest was significantly higher than in patients with hypospermatogenesis and complete spermatogenesis (P＜0.05).There was no difference in serum follicle stimulating hormone levels in patients with hypospermatogenesis and complete spermatogenesis.The follicle stimulating hormone receptor expression level of testicular samples with Sertoli cell-only syndrome was significantly higher than in those with hypospermatogenesis,maturation arrest,and complete spermatogenesis (P＜0.05),but no significant difference was observed among hypospermatogenesis,maturation arrest,and complete spermatogenesis testicular samples.Conclusions Different serum follicle stimulating hormone levels and follicle stimulating hormone receptor expression were found in the different testicular histology phenotypes in azoospermic patients.Differential follicle stimulating hormone receptor expression in testicular tissue of patients with idiopathic azoospermia may be associated with the degree of spermatogenesis.