抄録
Investigation has been made to develop a new method of assay for heavy metal detoxicants by utilizing the deposition pattern of heavy metal salts in the incisal dentin of rabbits. The results obtained are as follows. 1) Under a subcutaneous injection of 500 mg/kg of the lead (II) salt of Amberlite IRC-50 (Pb-A) suspended in 5% gum arabic, measurements were carried out of lead concentration in the blood in all of and its content in the urine in some of animals by the dithizone method. Single injection of this suspension brought about a continuous release of lead ions into the blood for a long period of time. The duration and amount of the release of the ions differed according to the sort of resin in the formation of the lead compound. 2) Lead ions released from Pb-A into the blood were deposited as lead salt in the incisal dentin which showed a continuous appositional growth. 3) The pattern of the deposition of lead salt in the dentin depended upon the time course of lead ion concentration in the blood. 4) The subcutaneous injection of Pb-A had almost no effect on the body weight. 5) From the foregoing results the possibilities were concluded that the assay of heavy metal detoxicants are performed without inducing the death of animals, and that, several detoxicants are assayed simultaneously with the use of one and the same animal, and moreover that, by administrating lead acetate at a certain interval, there are determined, as to the action of detoxicants, the potency, the duration and the time required for appearance.
