Attempts to inhibit testicular growth in rainbow trout with antiandrogens (cyproterone, cyproterone acetate, oxymetholone) and busulfan given during the period of spermatogenesis
1982
Billard, Roland | Laboratoire de physiologie des poissons ; Institut National de la Recherche Agronomique (INRA)
International audience
Show more [+] Less [-]English. We tried to inhibit spermatogenesis in adult male rainbow trout by giving them a daily diet (1% of body wt) containing antiandrogens—cyproterone, cyproterone acetate (Schering), oxymetholone (Syntex)—at dose of 20 or 40 mg/kg in the food, or by injecting an antimitotic agent, busulfan (Misulban, Techni-pharma), at doses of 10 mg/kg of body weight twice a month for 153 or 162 days, over the main period of testicular activity. When the cyproterone acetate and oxymetholone treatments were started before initiation of spermatogenesis, there was no testicular growth, but when spermatogenesis had already begun in June, the inhibitory effect of these drugs was limited; cyproterone acetate in that case had no effect at all. A limited number of spermatogonia were present in the undeveloped testis, suggesting that the effect could be reversible. GTH secretion was not suppressed, indicating that the drug had a direct effect on the gonads. During the experiment, body weight increased by 18% in the control group. In the groups given inhibitory treatments, body weight decreased slightly (6%) with cyproterone acetate but was markedly reduced (10%) after the oxymetholone treatment. Large-scale experimentation is necessary to test the effect of these drugs on growth. In conclusion, it appears that only cyproterone acetate, preventing male sexual maturation, is of interest in fish culture. It may also prove to be a useful tool for laboratory experimentation.
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