However, there was no evidence of continued synthesis in the cryptorchid testis, and measurement of total testosterone in testicular homogenates collected immediately postmortem also confirmed that intratesticular testosterone levels in the cryptorchid rat were as high as, if not higher than, those in normal testes. Comparison of the IF testosterone levels and the total testicular testosterone values also indicated that testosterone is concentrated within the testicular interstitial tissue, as reported in previous studies. Finally, extraction of testicular IF did not indicate the existence of any hidden differences in bound reserves of testosterone not detected by the direct testosterone RIA. buy cipro
The reason for the discrepancy in testosterone levels within the cryptorchid testis in different studies is not known, but it may involve differences in blood flow and testosterone clearance. Induction of experimental cryptorchidism requires considerable manipulation of the testis and its associated vasculature. This manipulation may have variable effects on blood supply and drainage, including the countercurrent exchange mechanisms that regulate testosterone release from the testis via the blood. Slight differences in surgical technique could account for differences in the vascular mechanisms that regulate testosterone levels within the interstitial tissue, with potentially different outcomes for the eventual intratesticular testosterone levels. In any case, these data emphasize the importance of confirming intratesticular testosterone levels in all experiments where testicular function is altered.