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It is well known that the erythrocyte δ-aminolevulinic acid dehydrase (δ-ALAD) activity is readily altered in the earliest stage of lead exposure, and its measurement is a common practice as a screening test of lead workers in industry. As it has been proved that the δ-ALAD activity is affected not only by lead but also alcohol and a variety of metals, we intended to investigate how erythrocyte δ-ALAD activity varied in relation to blood alcohol level, and whether any modification of criteria already set for the screening of lead workers was necessary when they drank alcohol after lead work. Sprague Dawley albino male rats weighing 200∼250gm were divided into 3 groups : ethanol, lead nitrate and the combined groups, 0.06ml of 50% ethanol, 0.05ml of 1% lead nitrate and simultaneous administration of the both agents per 10 gm of body weight, respectively, into the abdominal cavity ; together with 2 control groups, one was normal and the other was dextrose group to which 0.11ml/10gm of body weight was injected into the abdominal cavity to produce equivalent calories with ethanol, 0.06ml/10 gm of body weight. Blood lead were measured with dithizone method of Keenan et al., blood alcohol with dichromate method of Widmark, and erythrocyte δ-ALAD activity with Bonsignore’s method modified by Weissberg et al. Following were the results obtained: 1. Erythrocyte δ-ALAD activity was immediately reduced after the injection of 50% ethanol, showing the least activity of 6.5±1.56 units/ml RBC 1 hour following the injection. The activity recovered with the same pace as the blood alcohol level returned normal, showing the activity of 23.0±1.36 units/ml RBC 16 hours following the injection. Control value of the δ-ALAD activity in the normal rat was 30.1±3.43 units/ml RBC. 2. Erythrocyte δ-ALAD activity was inversely correlated with blood alcohol level with coefficient of correlation r=-0.63(p＜0.01). Regression of erythrocyte δ-ALAD activity(y) on blood alcohol level(x) was expressed by the following equation, y=-41.67x+23.06. 3. Erythrocyte δ-ALAD activity was inhibited immediately after the administration of 1% lead nitrate and the activity kept on lowered showing 14.2±0.62 units/ml RBC and 6.37±1.14 units/ml RBC 1 hour and 16 hours following the injection, respectively. 4. Blood lead concentration reached the maxinum value of 435±21.28 ㎍/100ml 2 hours following intra-abdominal injection of 1% lead nitrate, 0.05ml/10gm of body weight. The blood lead concentration gradually decreased hereafter showing 161.7±51.07 ㎍/100ml 16 hours following the injection. 5. There was an intimate inverse correlation between erythrocyte δ-ALAD activity and blood lead concentration with the coefficient of correlation r=-0.94 (p＜0.01). Regression of erythrocyte δ-ALAD activity(y) on blood lead concentration(x) was expressed by the equation of y=-0.04x+28.75. 6. When the same amount of 50% ethanol was simultaneously administered with the 1% lead nitrate of the same dose, reduction of erythrocyte δ-ALAD activity 0.5, 1,2,4,8, and 16 hours following the injection was accelerated showing the reduction of 35.0%, 32.3%, 31.3%, 12.7%, 13.3%, 16.9% and 33.0% respectively. 7. In case of the simultaneous administration of alcohol and lead, both alcohol and lead concentrations in the blood were maintained higher levels and longer period of time than in case of alcohol or lead alone was administered. In summary of the above results, it can be said that alcohol adversely affects the erythrocyte δ-ALAD activity and aggravates the interference of heme biosynthesis induced by lead absorption. It is, therefore, recommended that lead workers are advised not to drink alcohol. Chronic effects of alcohol on lead workers and extent of the harzards on human subjects should be further investigated.
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