Reversible effect of testosterone undecanoate injection on spermatogenesis in rats.
OBJECTIVE
To study the effect of testosterone undecanoate (TU) injection on spermatogenesis in rats.


METHODS
Twenty adult SD rats received vehicle or TU (8 mg/kg, 19 mg/kg or 625 mg/kg) injection, im, every 15 days for 60 days, and another 38 animals received similar treatments for 130 days with half of them undergoing a recovery phase of 120 days (5 rats for each treatment). At the end of the treatment, testes were removed and the diameter of the seminiferous tubules and the number of late elongated spermatids (steps 15-19) per testis were estimated with stereological methods as a measure of the spermatogenic efficiency.


RESULTS
Low dose (8 mg/kg) TU treatment virtually had no effect on spermatogenesis. A dose of 19 mg/kg slightly suppressed spermatogenesis 60 days after treatment, and severe suppression occurred after another 70 days of dosing. Spermatogenesis was completely recovered at the end of the recovery phase. Large dose (625 mg/kg) TU treatment did not significantly affect spermatogenesis and was well tolerated by animals.


CONCLUSIONS
TU injection reversibly suppresses spermatogenesis in rats.
Morphometric Research Laboratory, North Sichuan Medical College, Nanchong, China.
X H
XH
Wen
X H
XH
Wang
J S
JS
Tong
Z W
ZW
Yang
G Y
GY
Zhang
D000818:Animals; D007267:Injections; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013091:Spermatogenesis / Q000187:drug effects*; D013739:Testosterone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D045165:Testosterone Congeners / Q000494:pharmacology*
D045165:Testosterone Congeners; D013739:Testosterone; C010792:testosterone undecanoate