DETERMINATION OF THE SITE OF METABOLISM OF TOTAL, FREE, AND COMPLEXEDPROSTATE-SPECIFIC ANTIGEN

Objectives. To determine the site of metabolism of total prostate-spec ific antigen (tPSA), free PSA (fPSA), and complexed PSA (cPSA). Method s. A total of 20 male patients, 50 years old or older, having a clinic al indication for left and right heart catheterization were enrolled i n this study. Selective blood samples were obtained from the infrarena l, infrahepatic, and suprahepatic inferior vena cava, renal vein, hepa tic vein, superior vena cava, pulmonary artery, and femoral artery. cP SA concentration was accepted as the difference between tPSA and fPSA concentrations. Results. We found that tPSA and fPSA concentrations in the infrarenal inferior vena cava were significantly higher than in t he systemic artery. There was no significant difference between the sy stemic artery and the infrarenal inferior vena cava for cPSA concentra tion. Although fPSA concentration decreased significantly across the r enal circulation, the decreases in cPSA and tPSA concentrations were s tatistically insignificant. In the hepatic circulation, we found that tPSA, fPSA, and cPSA concentrations were significantly decreased. No d ecrease in tPSA, fPSA, and cPSA concentrations were noted across the p ulmonary circulation. Conclusions. Our results indicate that fPSA and tPSA are released into serum from the prostate but the prostate may no t have a significant role in complex formation of PSA. In addition, th e liver has a significant role in the elimination of tPSA, fPSA, and c PSA. By contrast, the kidneys have a significant role only in the elim ination of fPSA. We also found that the lungs did not have a significa nt role in the elimination of tPSA, fPSA, or cPSA. UROLOGY 52: 470-473 , 1998. (C) 1998, Elsevier Science Inc. All rights reserved.