Permanent testicular damage induced in rats by a single dose of tunicamycin.

Tunicamycin administered as a single subcutaneous dose of 200 micrograms/kg caused permanent destruction of seminiferous tubules in adult male rats. The fertility of females was unimpaired by doses of up to 450 micrograms/kg. Degenerative changes in seminiferous tubule epithelium commenced 3 to 5 days after injection and by day 19 affected 95% of tubule profiles in sections. In 95% of tubules only Sertoli cells survived to day 56. Tubules without any surviving cells were present from day 19 and slowly increased in number, a variable proportion becoming mineralised. No regeneration occurred within one year. Leydig cells became more prominent because of the atrophy of seminiferous tubules, but their total mass did not differ significantly from that of control rats, nor did the plasma concentration of testosterone. Changes in tissues other than the tests were transient. The testicular damage seems to have resulted from localised ischaemia caused by tunicamycin-induced vasoconstriction.