| Summary: | 碩士 === 中國醫藥學院 === 環境醫學研究所 === 82 === For a long time lead is considered poisonous to the male reproduction system. However, the role of testosterone cannot be ignored when speaking of the influence that lead has on the male reproduction system. Testosterone has a very close relationship with spermatogenesis. Presently researches related to lead poisonous effect on testosterone have reached inconsistent conclusions.
This research is to investigate lead influence on testosterone secretion. Ten-week old rats(Sprague-Dawely strain) were used in the experiment. On the first day of a single-dose test, one lead acetate intraperitioneous injection was conducted (150mg/Kg, 100mg/Kg, 50mg/Kg, 0mg/Kg). Blood samples were taken on the 2nd day, the 7th day, and the 15th day; for repeated-dose tests, lead acetate intraperitioneous injection was conducted once a day (50mg/Kg, 25mg/Kg, 10mg/Kg, 0mg/Kg) for fourteen days. Blood samples were taken on the 15th day, the 30th day and the 60th day.
The results of the research suggested that the weights of the rats decreased as the dosage of lead acetate increased. However, the rats regained their normal growth after lead acetate injection was ceased. The weights of the testes were not so easily affected by lead when compared with the weights of the epididymis. After discontinued the lead acetate intraperitioneous injection, the blood, the testes, and the lead percentage in epididymis started to decrease. The lead percentage in testes was obviously lower than that in epididymis. It showed that testes were less sensitive to lead.
In the single dose test with lead acetate intraperitioneouns injection, the rat serum testosterone did not show any differences among the test groups on the second day. However, on the 7th day the serum testosterone of the group with the higmest dosage is obviously lower than that of other groups (p<0.05); In a repeated dosage test, the concentration of serum testosterone decreased as the dosage increased (p<0.05). This situation was gradually improved after discontinued the lead acetate intraperitioneous injection Testes testcsterone secretion ability deteriorated as the dosage of Iead acetate increased (p<0.05). Normally LH and c-AMP would stimulate the Leydig cells separated from normal rats, making the Leyding ceells to secrete testosterone. The experiments showed that this ability was not influenced wihtin 14 hcurs of Leydig cells culture. The above results show that the testosterone secretion ability for testes was indeed influenced by lead. However, Leydig cells would not poisoned by lead in a short period of time (14 hours) when cultured of in vitro. Lead would have its effect on the concentration of serum testosterone after a longer period of exposure. In addition, the decrease of serum testosterone concentration was due to lead suppressive effect on the testosterone secretion sbility of the testes.
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