Rapid Exponential Elimination of Free Prostate-Specific Antigen Contrasts the Slow, Capacity-Limited Elimination of PSA Complexed to Alpha1-Antichymotrypsin From Serum

Abstract

The main proportion of PSA-F is rapidly eliminated from serum, possibly by glomerular filtration. PSA-F released during surgery did not form complexes with ACT, as suggested by the lack of PSA-ACT elevation in serum. The size (approximately 90 kDa) and the extensive in vitro stability of the PSA-ACT complex prevents renal clearance. The nonexponential elimination of the PSA-ACT complex is evidence of a capacity-limited process (e.g., metabolic transformation).