造精機能障害に関する実験的研究 第2編: カドミウム塩の睾丸および諸臓器におよぼす影響について

Abstract

Parizek (1957) demonstrated marked destructive change s of testicle in rats following subcutaneous injection of small doses of Cd-salt. The weight of testicle markedly decreased as well as decrease in weight of adnexal organs. Furthermore he observed that the destructive effect of Cd-salt to testicle is prevented by simultaneous administration of Zn-salt. He suggested a competive inhibition between Cd- and Zn-salts on testicle. Experimental studies were designed with the relation to a b ove results to observe : (1) whether or not the weight-decreasing effect of Cd-salt is towarded to only testicle (and adnexal organs), (2) how the administered Cd-salt is concentrated in the testicle and how the concentration of Cd-salt is altered by administration of Zn-salt. Experiment 1 : According to the original meth o d of Pal-izek, 0.004 Mol CdC12 solution (1 ml containes 0.45mg Cd) and/or0.4 x1Zn-acetate solution were given subctaneously to rats, weighed 120-180gm. In 2, 4 and 6 weeks, such organs as testicle, epididymis, prostate, seminal vesicle, adrenal gland, pituitary gland, thymus, kidney, liver, spleen and heart were extirpated and weighed to calculate the organ weight per 100gm of body weight. With administration of Cd-salt (1m1 per 100gm body weight), marked decrease in weight of testicle and adnexal organs and increase in weight of adrenal gland were observed in 2 weeks. In 4 weeks, increase in weight of pituitary gland decrease in weight of kidney were seen in addition to the above changes. These changes were prevented by administration of Zn-salt (3m1 per 100gm body weight) except for adrenal gland which remained to be heavier. In 6 weeks, increase in weight of thymus was demonstrated in addition to the changes observed in 4 weeks. Namely the decrease in weight of testicle, prostate, seminal vesicle, epididymis and kidney and the increase in weight of adrenal gland, pituitary gland and thymus were statistically significant. These patterns were similarly observed in castrated group and castrated plus Cd-salt administered group. Experiment 2 : A s same as the experiment 1, Cd-salt and Zn-salt were given to rats. In addition, 1 ml of InraCd (NO3)2 solution (100pc/m1) (obtained from Radiochemical Centre and diluted with distillted water) (containing 0.096 mg Cd) was injected subcutaneously to each rat. In 18 and 90 hours, the rats were exsanguinated and extirpated such organs as testicle, epididymis, prostate, seminal vesicle, adrenal gland, thymus, liver, kidney, lung, spleen, heart, pancreas and small intestine. Following measurement of wet weight, a part or total of each organ was homogenized and its radioactivity was determined with Well-type scintillation spectrometer. Content of 115mCd in different organs was found as follows. (1) Liver showed an exceedingly high content (47.4 % in 18 hours and 38.7 % in 90 hours). Simultaneous administration of Zn-salt made the content at both times to be decreased. (2) Kidney was the second place (1.55 % in 18 houus and 2.73 % in 90 horus) and also showed significant increase with simultaneous administration of Zn-salt (2.54 % and 3.53% respectively). (3) Small contents were observed in testicle, thymus, lung, spleen and heart (0.05 %-0.2 %). With simultaneous administration of Zn-salt, decrease in radioactivity was seen in such organs except for testicle in 90 horus, but the change is only significant in lung. spleen and heart in 90 hours. (4) Epididymis, prostate, seminal vesicle and adrenal gland showed very small content (below 0.05 %). No. significant change was demonstrated even with simultaneous administration of Zn-salt. Content of u5 m Cd per gram of various organs was high in liver, kidney and pancreas (5 %-1 %), followed by spleen, small intestine, adrenal gland, heart, thymus, seminal vesicle, prostate, lung and epididymis. Testicle showed the lowest content (0.05 %) among the organs examined. A significant decrease in 90 hours after simultaneous administration of Zn-salt was observed in epididymis, seminal vesicle, lung, heart and small intestine. Content in testicle was 0.098±0.007% in 18 hours, which de c reased to 0.070±0.006 % in 90 hours. However, content per grams of testicle was not changed between the two observation times, becase weight of testicle decreased in 90 hours. In the group given Zn-salt simultaneously, the contents were found to be 0.088±0.013 % in 18 hours and 0.091±0.010 % in 90 hours, which showed no difference between two observation time in absolute content as well as content per gram of testicle. Furthermore, in 90 hours, content in simultaneous Zn-salt treated group is slightly higher than that in Cd-salt single treated group, but there was no difference in content per gram of testicle between these two group, since the former has higher weight than the latter, therefore, the 4 values of content per gram of testicle showed very closed results (0.05 %) which was the lowest one among various organs examined.