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Effects of high dose cancer therapy in testis
• Germ cell toxicity shows no age-dependency
• Toxic insult with HIGH INTENSITY
o Depletes spermatogonial stem cell pool
→ Permanent spermatogenetic failure = azoospermia
• Toxic insult with NEARLY STERILIZING INTENSITY
o Surviving spermatogonial stem cells begin to proliferate and
repopulate the tubules
→ Recovery follows, but takes time!
• Androgen production - less sensitive → OFTEN REMAINS. www.helsinki.fi/yliopisto 26.5.2018 9
Recovery at different stages of
spermatogenesis
• Even moderate gonadotoxic doses produce azoospermia that lasts longer than the 12 weeks
• Recovery is delayed for months or decades if gonadotoxic therapy kills stem cells
4 weeks
3 weeks
5 weeks
Adapted from Rowley et al. Radiat Res 1974;59:665–78
www.helsinki.fi/yliopisto 26.5.2018 10
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