The influence of temperature on human Leydig and Sertoli cell functions was investigated in vitro using the organ culture technique. Specific 125I-FSH and 125I-hCG binding sites in testes from patients with prostate cancer cultured for 1, 3, 5 or 7 days at 33 degrees C or 37 degrees C were measured and compared. There were no significant differences in 125I-FSH or 125I-hCG binding sites between the two temperature groups at 1 to 7 days of culture. Testosterone concentration in the medium obtained from testicular organ culture at 33 degrees C did not differ significantly from that at 37 degrees C at 1 to 7 days of culture. In conclusion, a high temperature may not disturb the Leydig and Sertoli cell functions in a short term.