Schlick E, Friedberg K D
Arch Toxicol. 1980 Jan;43(3):213-20. doi: 10.1007/BF00297586.
After a single intraperitoneal administration of lead in very small doses [1--100 micrograms Pbac/kg body weight (bw)], there was a dose-dependent, highly significant inhibition of erythrocyte D-aminolevulinic acid dehydratase (D-ALA-D) activity in mice. The maximal inhibition occurred between 3 and 24 h post injection (p.i.). After that, a rapid recovery of the D-ALA-D activity took place so that four days after lead administration, enzyme activity exceeded even the normal value. Only after eight days p.i. did the D-ALA-D value return to the initial level after a biphasic course. After 10 i.p. injections of 0.1 to 10 micrograms Pbac/kg bw, there was again a dose-dependent, highly significant inhibition of the erythrocyte D-ALA-D activity in mice. The maximal inhibition was shown to be 24 h after the last lead injection. In contrast to the single i.p. administration, however, we found a monophasic course for the return of D-ALA-D activity. The D-ALA-D values did not exceed the normal range at any time after 10 i.p. lead injections. Ten and 30 days oral administration of lead corresponding to i.p. doses exhibited similar results in D-ALA-D inhibition.
给小鼠腹腔内单次注射极少量的铅[1-100微克乙酸铅/千克体重（bw）]后，红细胞δ-氨基乙酰丙酸脱水酶（D-ALA-D）活性出现剂量依赖性的高度显著抑制。最大抑制作用出现在注射后3至24小时。此后，D-ALA-D活性迅速恢复，以至于在给予铅后四天，酶活性甚至超过正常值。仅在注射后八天，D-ALA-D值经过双相过程后恢复到初始水平。经腹腔内注射10次，每次剂量为0.1至10微克乙酸铅/千克体重后，小鼠红细胞D-ALA-D活性再次出现剂量依赖性的高度显著抑制。最大抑制作用显示在最后一次注射铅后24小时。然而，与单次腹腔内给药不同，我们发现D-ALA-D活性恢复的过程是单相的。在经腹腔内注射10次铅后，D-ALA-D值在任何时候都未超过正常范围。口服相当于腹腔内注射剂量的铅，持续10天和30天，在D-ALA-D抑制方面表现出类似的结果。
