Effect of nitrofurazone on the incorporation of L-lysine-U-14C into protein of rat testis

The nitrofuran group of chemotherapeutic agents has long been known to exert specific histological changes in the testicular germinal epithelium of the rat,¹ mouse,² and dog.³ These changes involve the arrest of spermatogenesis at the primary spermatocyte stage.⁴ The histological architecture of the nitrofuran-treated testis of the rat therefore closely resembles that of the cryptorchid rat testis in being characterized by a virtual absence of all the spermatids and mature spermatozoa. Recent data from this laboratory have indicated that the induction of experimental cryptorchidism in the rat results in a marked increase in the incorporation of l-lysine-U-¹⁴C into protein of the remaining cells of the seminiferous germinal epithelium.^5,6It appears that the loss of spermatids and spermatozoa from a nitrofuran-treated testis offers a unique opportunity to make a selective study of protein labeling of the remaining cells of the seminiferous epithelium as they exist in the natural environmental temperature of the scrotal sac rather than as they exist after exposure to the higher environmental temperature of the abdominal cavity as is necessarily the case in experimental cryptorchidism. The present studies were therefore designed to investigate the incorporation of radioactive lysine into protein of the remaining cells of the testis after the oral administration of nitrofurazone to adult rats.