Artificial chemical substances are ubiquitously distributed in the environment. Some of these environmental pollutants disturb the endocrine and immune function in wildlife and humans. Associate Prof. Yuji Makita investigates the effects of perinatal exposure to tributyltin and/or organochlorine compounds on offspring in animal experiments using rats. When tributyltin chloride was administered to mother rats during the perinatal period, the weight of thymus was decreased to 85-90 % of the normal value in rat offspring exposed with tributyltin via mother. Further, he found that tributyltin selectively affected helper T-cells. He is a specialist in environmental toxicology for humans. He also investigates the effects of perinatal exposure to para-dichlorobenzene on offspring, which is used as a moth repellent or room deodorant.