THE TOXICITY OF OPTICALLY INACTIVE, d- AND l-SELENIUM-CYSTINE

¹ South Dakota Agricultural Experiment Station, Brookings, South Dakota

In the first series (series 145) the toxicity of seleniferous wheat, selenium-cystine, and sodium selenite was compared by administering the different forms of selenium orally. Growth curves, daily food intake, macroscopic examination of the various organs, and selenium analysis all seemed to indiate that the toxicity of selenium-cystine was very similar to the toxicity of seleniferous wheat.

In the second series (series 146) the same compounds were compared and the same results obtained. However, this series contained an additional group which was fed a ration containing selenium-cystine and was given drinking water containing 10 p.p.m. of arsenic, in order to note whether arsenic would give protection against selenium-cystine toxicity as it had previously protected against the toxicity of selenium in seleniferous wheat. It was noted that arsenic gave full protection against the toxicity of selenium in selenium-cystine.

A third series of albino rats were used to compare the percentage excretion of selenium when the three seleniferous rations were administered. Both urine and feces selenium was determined and from the total amount of selenium ingested the percentage excretion was calculated. There was no significant difference in the amount of selenium excreted when the different rations were given.

d-Selenium-cystine was found to be moderately toxic while l-selenium-cystine appears to be the most toxic organic selenium compound that we have had occasion to feed to animals.

All results seemed to indicate that there could be a relationship between the compound which contains the selenium in cereal foods and selenium-cystine. Since it has been found that selenium in cereals is organic there may be a replacement of the sulfur by selenium in some sulfur containing compound or compounds which are present in the cereals.