To examine the effects of pesticides on farmers working in vinyl-covered greenhouses, subacute toxicity tests were conducted on rabbits exposed in the greenhouse a period of three months to zinc ethylenebis-dithiocarbamate (ZED) and N-trichloromethylthio-tetrahydrophthalimide (NTT), which had been sprayed once or twice a week. As a result, the authors have arrived at the following conclusions:
1) Either ZED or NTT did not inhibit the growth of the rabbits during the period.
2) Any significant changes attributable to the spraying of both pesticides were not detected in blood, urine and biochemical examinations.
3) Pathohistological examination showed the infiltration of polymorphonuclear leukocytes and histocytes in the interalveolar tissue of the lungs of the NTT-exposed rabbits. However, in the case of the ZED-exposed group of rabbits, the infiltration was so slight that there was veritably no difference from the control group.
In the brain, heart, liver, kidney, spleen, suprarenal gland, stomach and intestines, there were no abnormalities worth mentioning.
4) In several cases of the NTT-exposed group, inflammation was observed in their eyes and skins, whereas nothing abnormal were observed in the ZED-exposed group.
5) The concentration of ZED in air within the vinyl greenhouse at a time of spraying was 0.35mg/m3 and NTT measured 0.20mg/m3. After a lapse of one hour, either pesticide was undetectable.

Each of the 1, 000-times dilute solution of both drugs, Salithion and Sumithion, were experimentally sprayed over rabbits in vinyl greenhouses at a rate of five hours a day for three consecutive days. Changes in the residual quantity of the drugs in the blood and also in the quantity of PNMC, a metabolite of Sumithion in urine, were measured with the passage of time after the spraying. At the same time, the liver functions of the rabbits were checked and they were also subjected to a urinalysis and a pathohistological examination. The conclusions drawn from these studies are as follows:
1) No abnormal findings were observed on the appearance of the rabbits exposed to Salithion and Sumithion. Nor were there any abnormalities in the ophthalmologic findings, especially, in the funduscopic findings, at 10 and 30 days after the spraying of these drugs.
2) The residual quantity of both drugs in all the experimented rabbit's blood was measured immediately after the spraying. However, these drugs later disappeared rapidly from the blood, and they could not be detected 10 days after the spraying.
3) There was a significant rise in the quantity of PNMC 24 hours after the spraying. Later, it decreased rapidly. Ten days after the spraying, its values returned to normal level before the spraying.
4) With respect to the serum ChE level, the changes in the groups exposed to Salithion and Sumithion were the same as those in the control groups. So, any influences were not observed on serum ChE by the spraying of these drugs.
5) In the liver function test, urinalysis and pathohistological examination, no abnomal findings attributable to the inhalation of both drugs were observed.
6) The drug concentration in the air in the vinyl greenhouses at the time of their spraying was 61.5μg/m³ for Salithion and 30.1μg/m³ for Sumithion.

In the previous report, we concluded that chances are very slim for Salithion and Sumithion to concentrate in rabbits as these organophosphorous compounds are excreted quickly. This conclusion was inferentially drawn from the results of measurements of concentration of Salithion and Sumithion residues in the blood after experimental exposures of rabbits to the pesticides.
In the present report, we will discuss the same toxicological problem based on our findings in a series of experiments using rabbits with hepatic disturbances induced by carbon tetrachloride (CCl₄).
Rabbits were divided into three groups. One consists of rabbits having light hepatic disorder. They were subcutaneously injected with 0.1ml/kg of 20% CCl4 olive oil for three days consecutively. Under the second group come rabbits with moderate liver disturbance caused by the injection of 0.3 ml/kg of 20% CCl₄ olive oil. The injection was also made for three days. The remaining group is the control group.
These rabbits were administered orally with 5mg/kg and 20mg/kg of Smithion for three days running.
The examination covered (1) Sumithion residue level in the blood, (2) PNMC level in urine, (3) hepatic function (ChE, GOT, GPT, BSP, Al-P, BUN), (4) urinalysis and (5) histopathological examination of the liver and the kidney. The results of these tests were studied in comparison with those of the control group.
The following is a summary of our conclusion:
1) In the control group, Sumithion residues in the blood disappeared quickly, and could not be detected 72 hours after administration.
2) As far as the disappearance of Sumithion and the excretion of PNMC are concerned, there was no significant difference between the control and the light and moderate liver disturbance groups of rabbits.
3) In the rabbits with CCl₄-induced liver disturbances, it was noted that the administration of Sumithion impeded serum and red-cell ChE activities to a remarkable extent, and delayed the recovery of the liver function.
4) However, the liver disturbance did not deteriorate. The histological observation of the liver and the kidney did not reveal any abnormality due to the administration of Sumithion, either.