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Effect of testicular extracts on proliferation of spermatogonia in the mouse
Abstract:
Two intraperitoneal injections with an interval of 4 h between them, of rat testicular extract into adult male mice causes a decrease in the production of A spermatogonia in the compartment of undifferentiated A (As, Apr and Aal) spermatogonia. A significant decrease in the total number of A spermatogonia in stages VII and VIII of the cycle of the seminiferous epithelium was found at 2, 4 and especially 5, 7 and 8 days after treatment. Extracts of rat liver and rat spleen were without effect. In addition, an extract of rat testis containing very few spermatogonia had no effect. It was concluded that the active substance in the extract is synthesized and/or specifically accumulated in the spermatogonial compartment of the testis. Thus the active substance is tissue-specific but not species-specific, since extracts of both rat and bull testes were effective after injection into mice. It is inferred from the data that the effect of injection of testicular extracts is unlikely to be due to cytotoxicity, hormonal changes in the tubular environment or to an immunologic reaction, but is probably due to a spermatogonial chalone. This chalone partially inhibits proliferation of early type A spermatogonia in the normal mouse testis.
Insights
Rat testicular extract significantly reduced A spermatogonia production in mice. This suggests a tissue-specific spermatogonial chalone inhibits early spermatogonia proliferation.
Area of Science:
- Reproductive Biology
- Cell Biology
- Spermatogenesis Research
Background:
- Spermatogenesis involves the proliferation of spermatogonia.
- Regulatory mechanisms controlling spermatogonial populations are not fully understood.
- The existence and nature of endogenous inhibitors of spermatogonial proliferation require investigation.
Purpose of the Study:
- To investigate the effect of testicular extracts on spermatogonial populations in mice.
- To identify the specific cell type responsible for the observed effects.
- To determine the nature of the active substance in testicular extracts.
Main Methods:
- Adult male mice received two intraperitoneal injections of rat testicular extract.
- Spermatogonial numbers were assessed at various time points post-injection.
- Control groups received liver, spleen, or low-spermatogonia testicular extracts.
Main Results:
- Rat testicular extract significantly decreased A spermatogonia production.
- A marked reduction in A spermatogonia was observed at 5, 7, and 8 days post-treatment.
- Liver and spleen extracts had no effect, and extracts with few spermatogonia were inactive.
- Both rat and bull testicular extracts were effective, indicating tissue-specificity but not species-specificity.
Conclusions:
- The active substance is synthesized or accumulated in the spermatogonial compartment of the testis.
- The effect is likely mediated by a spermatogonial chalone, a tissue-specific inhibitor.
- This chalone partially inhibits the proliferation of early type A spermatogonia.