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Immunochemical alterations, of hepatic δ-aminolevulinate dehydratase from ICR strain of mice exposed tio lead in vitro (10 mM Pb^++) and in vivo (intraperitoneal injection of Pb^++ 1.3mg per 10 grams of body weight) were investigated by Ouchterlony gel double diffusion analysis as described by Kabat and Mayer (1967) and Campbell et al. (1970). and two-dimensional immunoelectrophoresis by Laurell (1965). Rabbit antiserum against hepatic δ-aminolevulinate dehydratase from ICR strain of mice purified 230-folds by methods of Doyle and Schimke (1969) modified by Lee and Chung (1979) was prepared as described by Kenny (1971) and Alexander and Kenny (1973). Heat-treated (at 64℃, for 10 minutes) supernatants (45,000×g for 2 hours and 20 minutes) of various tissue homogenates were used as antigens. Ouchterlony gel double-diffusion analysis revealed that the antigenicity of the δ-aminolevulinate dehydratase was identical between those distributed in various tissues of the mice. Administration of lead in vivo, 3 hours prior to evisceration seemed to affect the antigenicity of the δ-aminolevulinate dehydratase, resulting in the production of an additional precipitation line on the gel diffusion slide. Normal hepatic δ-amiriolevulinate dehydratase from ICR strain of mice showed 3 protein peaks with mobilities of 1.01(peak A), 0. 80(peak C), and 0.43 (peak D) relative to the mobility (1.0) of bovine serum albumin fraction V (peak B). The immunoelectrophoretic pattern was identical with the normal δ-aminolevulinate dehydratase unaffected by the addition of lead in vitro whereas administration of lead in vivo induced an appearance of additional peak E with the relative mobility of 0.68. Three protein peaks that appeared in two-dimensional immunoelectrophoresis were considered as common protein fractions of δ-aminolevulinate dehydratase, and peak E as an unique protein fraction caused by de novo production of lead type δ-aminolevulinate dehydratase by addition of lead in vivo as suggested by Cantrell et al. (1977). These findings, therefore, could be an important. clue to the possibility of developing an immunological diagnostic tools for the evaluation of lead absorption. Further study would be required to determine the dose-response relationship between the amount of lead exposed and appearance and extent of production of the unique protein fraction.
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