Diuron is a ureic herbicide considered to have very low toxicity. The present study evaluated several aspects of reproductive toxicity of diuron in adult male rats. Diuron was diluted in corn oil and administered by oral gavage to groups of 18-20 rats at doses of 0, 125 or 250 mg/kg per day for 30 days; the control group received only the corn oil vehicle. At the end of the treatment period, approximately half the animals from each group were assigned to one of two terminal assessment lines: (1) reproductive organ, liver and kidney weights; measurement of diuron concentrations in liver and kidney; plasma testosterone determinations; evaluation of daily sperm production per testis; sperm number and sperm transit time in the epididymis; or (2) sexual behavior assessment during cohabitation with a receptive female; fertility and pregnancy outcome after natural mating; testicular, epididymal, kidney and liver histopathology; sperm morphology. After 30 days of oral diuron treatment, there were no treatment-related changes in body weights, but dose-related diuron residues were detected in the liver of all treated rats and absolute and relative liver weights were increased in both groups. There were no statistically significant differences between the treated and control groups obtained in plasma testosterone concentrations, or in parameters of daily sperm production, sperm reserves in the epididymis, sperm morphology or measured components of male sexual behavior. On the other hand, the number of fetuses in the litters from diuron-treated rats was slightly smaller than litters from control rats. Therefore, although the results did not indicate that diuron exposure resulted in direct male reproductive toxicity in the rat, they suggest that additional studies should be undertaken to investigate the possible effects on fertility and reproductive performance.

Reproductive effects in male rats exposed to diuron.

The role of nutrition in toxicology

Malnutrition is usually complex, many deficiencies occurring simultaneously. Changes occur in almost every organ of the body. Apart from the pathophysiological changes which occur in protein-calorie malnutrition, vitamin, mineral and trace element deficiency is accompanied by diverse metabolic changes in tissues. As a consequence there is large potential for alteration of drug response in malnutrition, not only because of possible changes in drug kinetics but also because of changes in tissue uptake and localisation of drugs and potential alteration in drug-receptor interactions. The risk of susceptibility to drug-induced damage may also be increased.

Drug Metabolism and Pharmacokinetics in Malnutrition

Nutritional factors influence the toxicity of some environmental pollutants. Pollutants of importance in such interactions are some pesticides, a number of minerals, and oxidant air pollutants. Nutritional factors of importance in these interactions are dietary protein, especially sulfur-containing amino acids, trace minerals, and vitamins A, C, D, and E. Agricultural and geographical factors and food processing procedures affect the interactions. Pathophysiological mechanisms seem to exist that suggest that common air pollutants and pesticides may act in a combined or synergetic fashion to pose an even greater threat to human health than has been recognized.

Vincent. Krupa

Papers

Protein-deficient diet and diuron toxicity.