Testosterone and androgen receptor in human nephrolithiasis.

Purpose: We investigated the relationship of kidney calculi with plasma free and total testosterone, and androgen receptor up-regulation in the kidneys of men with nephrolithiasis.

Materials And Methods: Male patients with kidney stone and healthy men were included in the study. Blood was collected in a tube containing 2% heparin in the morning. Total and free serum testosterone was measured by enzyme linked immunosorbent assay. All patients underwent percutaneous nephrostolithotomy. At the end of the procedure ultrasound guided puncture biopsy was done to acquire kidney tissue. Normal kidney tissue obtained at autopsy served as the control. Androgen receptor was detected in kidney tissue by immunohistochemistry. Stone composition was analyzed in each patient.

Results: The study included 37 male patients 22 to 39 years old and 31 healthy men 24 to 37 years old. All calculi were composed of calcium oxalate monohydrate or calcium oxalate dihydrate and a few also contained protein or uric acid. Mean±SD serum total and free testosterone was 13.29±4.79 ng/ml and 63.23±28.58 pg/ml in patients, and 7.30±0.82 ng/ml and 35.59±24.91 pg/ml in healthy men, respectively (each p<0.001). Immunohistochemistry revealed androgen receptor up-regulation in the kidneys of patients with nephrolithiasis.

Conclusions: Our data suggest the important role of enhanced androgen signaling in human nephrolithiasis.