[Effects of thymosin (fraction 5) on the endocrine function of the testis in mice].

The influence of the thymic hormone thymosin (fraction 5) on the hormonal function of testes form 2 months old BALB/c mice was investigated. It was shown that after 3 and 24 hours after thymosin administration there is a considerable decrease of plasma testosterone level as compared with the level of control animals, which were injected with BSA. 24 hours after administration of thymosin the in vitro production of testosterone by the testes was decreased essentially as compared with the control. Thymosin, injected together with indomethacin, inhibitor of prostaglandin synthesis, does not influence the hormonal activity of the testes. So, it was ascertained that thymic hormone thymosin participates in the regulation of the testes hormonal function. It is supposed that it's action on the gonads may be carried out through prostaglandins.