Influence of chronic alcohol consumption on hepatic heme and porphyrin metabolism

Abstract

To study the effect of prolonged alcohol consumption on hepatic heme and porphyrin metabolism, female Wistar rats were fed for 60 days a nutritionally adequate liquid diet containing 36% of total calories as ethanol, whereas the control diet was isocaloric and contained no alcohol. Compared to pair-fed controls, the administration of the alcohol diet resulted in an increased hepatic activity of δ-aminolevulinic acid synthase by 223% (112.3 ± 19.6 nmoles/hr/100 g b.wt. vs. 362.8 ± 42.5; P < 0.01), an enhanced urinary excretion of δ-aminolevulinic acid by 101% (64.8 ± 11.8 nmoles/day vs. 130.8 ± 22.4; P < 0.05), and an augmented urinary output of total porphyrins by 142% (1.2 ± 0.2 nmoles/day vs. 2.9 ± 0.5; P < 0.05). Concomitantly, the hepatic content of cytochrome P-450 was significantly enhanced and that of hepatic catalase activity marginally increased, whereas the hepatic iron content remained unaltered. In summary, the feeding of rats with a liquid alcohol diet for 60 days results in changes of hepatic heme and porphyrin metabolism which are associated and may be causally related with an induction of hepatic hemoproteins and subsequent derepression of hepatic δ-aminolevulinic acid synthase, whereas hepatic iron appears to play no pathogenic role.