Radiation dose and biological effects to mouse testis from sodium 32P-phosphate.

Radiation dose to mouse testis was estimated to be about 1.65 rad per microCi of intravenously injected 32P. This high dose to the organ was due to the incorporation of this isotope into the macromolecules of the testis. Up to 30% of the total testis activity was in DNA molecules. Biologic effects on mouse testis from 32P were determined by testis weight loss and the decrease in the number of sperm heads in the testis. Number of sperm heads reached a minimum of 1.3% of control 36 days after injection of 3.5 microCi/g body weight of 32P. Significant decreases in sperm head counts were observed after as little as 0.2 microCi/g body weight of 32P.