Abstract
Testicular necrosis induced by human chorionic gonadotrophin (hCG) was examined in rats with respect to the time-course of the histopathologic changes and to the differences in the sensitivity among ages and strains of rats. A single subcutaneous injection of hCG at a dose of 2, 000IU/kg produced focal necrosis of the seminiferous tubules and interstitial tissue in the frontal lower part of the testis of adult F344 rats followed by testicular weight changes. Degeneration or multinucleated giant cells at the seminiferous epithelium or edema and neutrophil infiltration in the interstitium were also observed in the necrotic area 1 day after treatment and thereafter, but no changes were noticed in the upper part of the testis. The necrotic change was induced in F344 rats at the ages of 11 weeks or older, but not at 5 weeks, indicating no susceptibility in the younger age. The sensitivity to hCG was highest in F344/Jcl rats followed by Sprague-Dawley, LEW, WKY, and Wistar rats in descending order. The maximum strain difference in sensitivity was approximately 300 times in hCG dose. These results indicate that hCG induces an acute focal necrosis in the seminiferous tubules that is age-dependent, with a great strain difference in sensitivity.
