Androgen receptor immunostaining and androgen receptor messenger ribonucleic acid expression are increased in cremaster muscles associated with undescended testis.

OBJECTIVES

To determine and compare androgen receptor (AR) immunostaining and AR messenger ribonucleic acid (mRNA) expression in cremaster muscles associated with descended or undescended testis.

METHODS

Eight boys with descended testis but with inguinal hernia and 8 boys with undescended testis were evaluated. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and free testosterone levels were determined, and samples of cremaster muscles were immunostained for AR. Groups were compared by unpaired t tests and Fisher's exact tests; P values of <0.05 were considered significant. Samples of cremaster muscles were obtained from another 5 boys with descended testis but with inguinal hernia and 5 boys with undescended testis. The expression of AR mRNA in those samples was determined by semiquantitative reverse transcriptase polymerase chain reaction.

RESULTS

Serum FSH, LH, testosterone, and free testosterone levels were similar among groups. None of the samples from boys with descended testis showed positive staining, but 4 of 8 samples from boys with undescended testis stained positive for AR. Androgen receptor mRNA transcript levels were approximately 10 times lower in cremaster muscles of boys with descended testis compared with those in boys with undescended testis.

CONCLUSIONS

Despite similar serum hormone levels, more AR expression in cremaster muscles associated with undescended testis might represent evidence of being subjected to a lesser degree of androgenic effects.