Abstract: | When 5-thio-D-glucose was fed to male mice at daily dose levels greater than 30 mg/kg sperm development was completely inhibited within 3 weeks and remained so without impairment of libido for the experimental period of 7 weeks. Removal of this substance from the diet resulted in a resumption of sperm development and fertility within 5 to 8 weeks. Normal litters were sired by males which had recovered after this treatment. |