トルエン暴露時の間脳-下垂体-副腎皮質系の反応に関する実験的研究

抄録

Diencephalon-hypohysis-adrenal cortex system is one of the most sensitive systems to harmful evironmental factors and this system has an important role for the organism to exist in the harmful environment. Takeuchi, one of the authors, in the previous experiment, obtained the. results that toluene vapor might effect diencephalon-hypohysis-adrenal cortex system and that the function of this system might decrease in the chronic exposure to toluene.
We think in order to make clear toxicity of organic solvents, it is very important to study the response of this system to organic solvents. And we performed the following animal experiments using male rats. As indices of the responce of diencephalon-hypohysis-adrenal cortex system, adrenal weight, 11-OHCS concentration in the blood, eosinophile count of the blood and thymus weight were determined.
The results are as follows :
1) In 8 hr exposure to 2000 ppm toluene vapor, adrenal weight and 11-OHCS concentration in the blood of the exposed animal increased significantly and eosinophile count of the blood decreased significantly in comparison with the control. But, 16 hr after the end of exposure, these significant differences were not found.
2) In 8 hr exposure to 1000 ppm toluene, adrenal weight and 11-OHCS concentration in the blood of the exposed animals significantly increased and eosinophile count of the blood was significantly smaller in comparison with the control as well. And in 8 hr exposure to 100 ppm toluene, the change of these indices was similar as in the case of 1000 ppm, except adrenal weight which did not significantly increase in comparison with the control. The changes of these indices in 8 hr exposure to 100 ppm toluene were larger than in the case of 100 ppm.
3) In the exposure of 8 hr a day for 4 weeks to 1000 ppm toluene, adrenal weight of the exposed animals increased significantly in comparison with the control after 2 weeks and became still larger after 4 weeks. Eosinophile count increased and after 4 weeks it was significantly larger than the control. 11-OHCS concentration in the blood of the exposed animals decreased after 1 week but the difference between the exposed and the control was not found after 2 weeks.After 4 weeks, 11-OHCS concentration in the blood of the exposed animals increased but this increase was statistically not significant in comparison with the control. The reactivity of these indices against the exposure to 1000 ppm toluene chan gedbetween the exposed and the control remarkably after 4 weeks.
From the results of these three animal experiments, it was found that the diencephalon-hypohysis-adrenal cortex system responses remarkably against the exposure to toluene vapor, and even in 8 hr exposure to 100 ppm toluene the changes of these indices are found, and in 4 weeks exposure to 1000 ppm toluene, the changes of these indices are cummulative.