Testicular Damages in Neonatally Estrogenized Adult Mice

In about 60% of adult male mice which had been given injections ofestradiol-17β for 15 days from the day of birth, 20μg daily for the first 10 days and 40Eg daily for the following 5 days, seminiferous tubules in the right or both testes lost practically all germinal elements, the tubular lumen being filled with a large number of leucocytes. When the testicular lesions occurred unilaterally, the affected testis was always the right one. At the age of 160-185 days, the greater part of the testicular parenchyma was replaced by proliferated connective tissue in some neonatally estrogenized mice. However, in the other animals, the testes were much less damaged, although the spermatogenic function was permanently in abeyance. The testes of neonatally estrogenized mice sacrificed at the age of 15 or 20 days were normal except for a slight fatty degeneration of the interstitial tissue. Adult males which had been given injections of estradiol-17β for 15 days from the 10th day after birth, 50μg for the first 10 days and 100Eg for the next 5 days, normally developed testes with active spermatogenesis.