The primary goal of the proposed studies is to determine the efficacy of perfluorochemicals as oxygen carriers for the in vitro perfusion of testis. Specifically, selected perfluorochemicals will be investigated as to their effect of testosterone secretion and histological features of testes perfused in vitro. The results will be important since steriodogenic function in animals or isolated organs exposed to perfluorochemicals has not been previously investigated. A significant aspect of the experimental design is that the control for every experimental observation will be the contralateral testis perfused in vitro with medium containing erythrocytes. Consequently, the influence of exposure to perfluorochemicals can be directly assessed by comparing the results derived by simultaneously perfusing both testes of an animal; one testis with perfluorochemicals and one testis with erythrocytes. Testosterone secretion by perfused testes will be quantitated with a specific radioimmunoassay. Light- and electron-microscopic examinations of non-perfused and perfused testes will provide a powerful tool for identifying histological and ultrastructural modifications caused by perfluorochemicals. Species-specific effects will be determined by including three species as experimental animals. A second facet of the proposed studies will be the standardization of emulsification procedures for perfluorochemicals selected for the in vitro perfusions. The studies are also designed to test the potential of testes perfused in vitro as a model for the biological screening of perfluorochemicals. To this end, perfluorochemical retention in organs in vivo and in testes in vitro will be compared. Together, these studies represent the first comprehensive examination of the influence that perfluorochemicals has on testicular function. Future research with perfluorochemicals will be prompted by any conclusion derived from the proposed studies. If testicular function in vitro is affected by perfluorochemicals, research will be stimulated that focuses on in vivo testicular function and the mechanisms by which perfluorochemicals exert their deleterious effects. Alternatively, if perfluorochemicals are proven to be efficient and conveniently-used oxygen carriers, their utilizastion as basic research tools will be encouraged.