THE UPTAKE OF PORPHYRIN AND ZINC-METALLOPORPHYRIN BY THE PRIMATE PROSTATE

The relative distribution of sensitizer drugs in the prostate and its contiguous organs is of importance in the treatment of localized prost atic cancer with photodynamic therapy. Using the primate model, whose prostate is both morphologically and physiologically homologous with i ts human counterpart, the distribution of hematoporphyrin derivative ( HpD) amongst organs of urological interest was determined. Hematoporph yrin derivative levels were comparatively low in both caudal and crani al prostatic lobes (0.93-1.77 mug/g) and were similar to those in rect um, urethra and the skin. The reticuloendothelial organs, liver, splee n and also the kidney accumulated the highest quantities of por-phyrin (4.76-9.8 mug/g, liver > spleen > kidney). Despite a high avidity of prostatic tissue for zinc, a zinc-metalloporphyrin (Zn-HpD) did not co ncentrate selectively in the prostate. The results are of clinical val ue in view of the homology between the primate and the human.