- Email: [email protected]
Effects of ethanol and propylthiouracil on hepatic iron and copper contents in the male albino mouse
Drug and Alcohol Dependence, 24 (1989) 261-263 Elsevier Scientific Publishers Ireland Ltd.
261
Effects of ethanol and propylthiouracil on hepatic iron and copper contents in the male albino mouse
E. Gonzblex-Reimers’, F. Santolaria-Fernbndeza, 0. Hernbndez-Torresb, V. Castro-AlemSnb, L. Galindo-Martinb, F. Rodriguez-Moreno’
and
R. Ferres-Torresc Hospital UniveT&a& de Can&as” (Dpto. de Medicine Inted, bDpto. de Q&mica Anal&a and ‘Dpto. de Anutomia y Anatomia Patoldgica. Facultad de Medicina, Universidad de La Laguno, Tenerife (Spain) (Received March 31st, 1989) With the aim to analyze whether propylthiouracil (PTU) alters ethanol-induced changes in liver iron and copper contents, 40 male albino mice were equally divided into a control group, an ethanol-treated group, a PTU-treated group and an ethanol + PTU-treated group. Twenty animals were killed at the age of 85 days and 20 at the age of 180 days. Liver iron and copper contents showed a progressive, statistically non-significant increase both in the controls and in ethanol-treated animals. Liver iron contents was significantly higher in the 180-day-old alcoholic mice as compared with controls. Animals treated either with PTU or with PTU + ethanol showed liver iron levels in the normal range, markedly different from the ethanol-treated animals (p < 0.005). Liver copper content of the ethanol-treated animals was higher (but not significantly) than that of the controls. Liver copper levels of the PTU + ethanol-treated animals were in the range of the ethanol-treated animals. Thus, PTU seems to revert an overload of ethanol-mediated iron of copper. Key words: alcoholism; propylthiouracil; iron; copper
Introduction Iron, copper and zinc play important roles as co-factors of several enzymes involved in collagen synthesis [1,2] and other metabolic pathways affected by ethanol [3]. On the other hand, liver contents of those elements become altered in chronic alcoholic liver disease [4], most of the pathogenetic mechanisms involved remaining obscure. Hepatic iron overload is commonly observed in 30% of alcoholics with chronic liver disease, although no relationship seems to exist between the presence of excessive iron and the severity of liver disease [5,6]. Iron in alcoholic beverages may play a role, as it happens in South African blacks [7]. An increased transferrin-bound iron uptake by the damaged liver [a], and an ethanol-mediated increased
intestinal absorption of iron have also been advocated [9]. In recent years a liver receptor to ferritin has been isolated in rats [lo] and later in men [ll]. It is actually unknown whether ethanol mediates its overactivity. On the other hand, increased copper accumulation promotes liver fibrogenesis; indeed, copper also plays a role in the activation of several enzymes involved in collagen synthesis [12,13]. Propylthiouracil (PTU) has been employed as a treatment of alcoholic liver disease [14-161, based on the drug-mediated inhibition of the ethanol-induced hypermetabolic state [17]. Although there are several experimental and clinical data which show a beneficial effect on PTU, there is still no general agreement regarding its therapeutic value [18]. Recently we have shown that PTU reverts
0376-8716/89/$03.50 0 1989 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
262
the ballooning of the hepatocytes derived from ethanol abuse [19]. In the present paper we examined whether in mice the administration of ethanol, PTU, or both leads to changes in hepatic iron and copper contents. Materials and methods
A total of 40 male albino mice were divided into four groups: a control group, an ethanoltreated group (by addition of ethanol to the drinking water at a concentration of 20°/61; a PTU-treated group (by addition of PTU both to the standard pellet diet at a concentration of 0.3% and to the drinking water at a concentration of 0.002%); and a fourth group, treated both with ethanol and PTU. All the animals were treated from birth. Twenty animals were killed on the 85th day of life and the others on the 180th day. Liver samples (with a mean dry weight of 48.59 + 7.27 mgl were analyzed for copper and iron using a Perkin Elmer 3030 B atomic absorption spectrophotometer equipped with a HGA 500 Perkin Elmer graphite camera. Results
showed a progressive Alcoholic mice increase in liver iron and copper contents when those killed at the 180th day were compared with those killed at the 85th day of life, differences being not statistically significant. The 85-day-old PTU- and PTU + ethanoltreated animals showed liver iron and copper levels which did not differ either from the controls or the alcoholic mice (Fig. 11. On the contrary, highly significant differences were observed between liver iron contents of the four groups of the 180-day-old animals CF = 6.70, P < 0.0051,differences being established between the ethanol-treated mice and the other three groups (Fig. 21. Both PTU- and PTU + ethanol-treated animals showed liver iron contents practically identical with those of the controls. With respect to liver copper, ethanol-treated animals showed higher concentrations than the
IO0 days
h5
140
Control group; - - Liver iron content. Fig. 1. Ethanol-treated group; . . -. - PTU-treated group; - * - * PTU + ethanol-treated group.
controls, but differences between the four groups were not statistically significant. However, the PTU + ethanol-treated animals showed liver copper levels very similar to those of the ethanol-treated mice.
’
1
Control group; Fig. 2. Liver copper content. -- Ethanol-treated group; * * * * * PTU-treated group; _._. - PTU + ethanol-treated group.
263
Discussion
Our results show that ethanol consumption is associated with an increase in liver iron content, a fact which is in accordance with other authors [5,6]. The underlying mechanism of ethanol-mediated iron overload still remains obscure. It has been proposed that the following may play a role: ethanol-mediated increased intestinal absorption [9]; increased absorption secondary to pancreatic damage [7]; increased uptake of transferrin-bound iron by the damaged liver [8]; favoured by the increased transferrin iron saturation [20,21] and increased availability of iron [22]. It is well known that hypothyroidism may reduce the absorption of iron [23]. This might explain our results concerning liver iron contents of the PTU + ethanol-treated animals. They could also be interpreted as the result of the general hypothyroid metabolic depression which could also affect liver iron uptake. PTU appears to counteract the effect of ethanol with respect to iron overload, but not regarding liver copper content. The liver regulates copper stores maintaining a highly efficient balance between albumin-bound copper uptake, biliary excretion and synthesis of plasma and tissue copper proteins [12]. In alcoholic cirrhosis high liver copper contents have been described [24], possibly as a result of impaired biliary excretion as well as decreased synthesis of copper protein. Hypothyroidism may reduce bile flow [25] and could thus affect the hepatic copper content, but this as well as a reduced uptake remains speculative. Nevertheless, our results demonstrate that PTU reverts the effect of ethanol on hepatic iron overload, a fact which is in accordance with the
protective role of this drug in ethanol-mediated liver injury. References 1 2 3 4
5 6 7 8 9 10 11 12 13
14 15 16 17 18 19 20 21 22 23
24 25
M. Rojkind and M.A. Dunn, Gastroenterology, ‘76 (19791849. H. Anttinen et al., Gastroenterology, 86 (19841532. E.J. Underwood, Trace Elements in Human and Animal Nutrition. Academic Press, New York, 1977. J.T. Galambos, Cirrhosis. In: L.H. Smith (Ed.), Major Problems in Internal Medicine, Vol. XVII, Saunders, Philadelphia, 1979. R.W. Chapman et al., Dig. Dis. Sci., 27 (19821909. P. Brissot et al., Gastroenterology, 80 (19811557. S. Sherlock, Diseases of the liver and Biliary system. Blackwell, Oxford, 1981. R.W. Chapman et al., Gastroenterology, 84 (19831143. R.W. Charlton et al., Br. Med. J., 2 (196411427. U. Mack et al., J. Biol. Chem., 258 (198314672. P.C. Adams et al., Hepatology, 8 (19881719. I. Sternlieb, Gastroenterology, 78 (198011615. N.W. Solomons. Zinc and copper in hepatobiliary and pancreatic disorders, In: Z.A. Karcioglu and R.M. Sarper (Eds.1, Zinc and Copper in Medicine, Charles C. Thomas, Springfield, 1980. H. Orrego et al., Gastroenterology, 76 (19791105. P. Hall& et al., Gastroenterology, 82 (19821925. H. Orrego et al., N. Eng. J. Med., 317 098711421. C.S. Lieber, N. Eng. J. Med., 319 (198811639. C.S. Lieber, Hepatology, 4 (1984) 1243. E. Gonzalez-Reimers et al., Drug Alcohol Depend, 21 (1988111. J. Lindenbaum and C.S. Lieber, N. Eng. J. Med., 281 (19691333. M.S. Wheby and L.G. Jones, J. Clin. Invest., 42 (19631 1007. MS. Wheby and G. Umpiere N. Eng. J. Med., 271 (19641 1391. S.H. Ingbar and K.A. Woeber, The thyroid gland. In: H. Williams (Ed.), Textbook of Endocrinology, Saunders, Philadelphia, 1975. S. Ritland et al., &and. J. Gastroenterol., 12 (1977) 81. K.E. Anderson and A. Kappas, Hormones and liver function. In: L. Schiff and E.R. Schiff (Eds.1, Diseases of the liver and biliary system, Lippincott, Philadelphia, 1982.
261
Effects of ethanol and propylthiouracil on hepatic iron and copper contents in the male albino mouse
E. Gonzblex-Reimers’, F. Santolaria-Fernbndeza, 0. Hernbndez-Torresb, V. Castro-AlemSnb, L. Galindo-Martinb, F. Rodriguez-Moreno’
and
R. Ferres-Torresc Hospital UniveT&a& de Can&as” (Dpto. de Medicine Inted, bDpto. de Q&mica Anal&a and ‘Dpto. de Anutomia y Anatomia Patoldgica. Facultad de Medicina, Universidad de La Laguno, Tenerife (Spain) (Received March 31st, 1989) With the aim to analyze whether propylthiouracil (PTU) alters ethanol-induced changes in liver iron and copper contents, 40 male albino mice were equally divided into a control group, an ethanol-treated group, a PTU-treated group and an ethanol + PTU-treated group. Twenty animals were killed at the age of 85 days and 20 at the age of 180 days. Liver iron and copper contents showed a progressive, statistically non-significant increase both in the controls and in ethanol-treated animals. Liver iron contents was significantly higher in the 180-day-old alcoholic mice as compared with controls. Animals treated either with PTU or with PTU + ethanol showed liver iron levels in the normal range, markedly different from the ethanol-treated animals (p < 0.005). Liver copper content of the ethanol-treated animals was higher (but not significantly) than that of the controls. Liver copper levels of the PTU + ethanol-treated animals were in the range of the ethanol-treated animals. Thus, PTU seems to revert an overload of ethanol-mediated iron of copper. Key words: alcoholism; propylthiouracil; iron; copper
Introduction Iron, copper and zinc play important roles as co-factors of several enzymes involved in collagen synthesis [1,2] and other metabolic pathways affected by ethanol [3]. On the other hand, liver contents of those elements become altered in chronic alcoholic liver disease [4], most of the pathogenetic mechanisms involved remaining obscure. Hepatic iron overload is commonly observed in 30% of alcoholics with chronic liver disease, although no relationship seems to exist between the presence of excessive iron and the severity of liver disease [5,6]. Iron in alcoholic beverages may play a role, as it happens in South African blacks [7]. An increased transferrin-bound iron uptake by the damaged liver [a], and an ethanol-mediated increased
intestinal absorption of iron have also been advocated [9]. In recent years a liver receptor to ferritin has been isolated in rats [lo] and later in men [ll]. It is actually unknown whether ethanol mediates its overactivity. On the other hand, increased copper accumulation promotes liver fibrogenesis; indeed, copper also plays a role in the activation of several enzymes involved in collagen synthesis [12,13]. Propylthiouracil (PTU) has been employed as a treatment of alcoholic liver disease [14-161, based on the drug-mediated inhibition of the ethanol-induced hypermetabolic state [17]. Although there are several experimental and clinical data which show a beneficial effect on PTU, there is still no general agreement regarding its therapeutic value [18]. Recently we have shown that PTU reverts
0376-8716/89/$03.50 0 1989 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
262
the ballooning of the hepatocytes derived from ethanol abuse [19]. In the present paper we examined whether in mice the administration of ethanol, PTU, or both leads to changes in hepatic iron and copper contents. Materials and methods
A total of 40 male albino mice were divided into four groups: a control group, an ethanoltreated group (by addition of ethanol to the drinking water at a concentration of 20°/61; a PTU-treated group (by addition of PTU both to the standard pellet diet at a concentration of 0.3% and to the drinking water at a concentration of 0.002%); and a fourth group, treated both with ethanol and PTU. All the animals were treated from birth. Twenty animals were killed on the 85th day of life and the others on the 180th day. Liver samples (with a mean dry weight of 48.59 + 7.27 mgl were analyzed for copper and iron using a Perkin Elmer 3030 B atomic absorption spectrophotometer equipped with a HGA 500 Perkin Elmer graphite camera. Results
showed a progressive Alcoholic mice increase in liver iron and copper contents when those killed at the 180th day were compared with those killed at the 85th day of life, differences being not statistically significant. The 85-day-old PTU- and PTU + ethanoltreated animals showed liver iron and copper levels which did not differ either from the controls or the alcoholic mice (Fig. 11. On the contrary, highly significant differences were observed between liver iron contents of the four groups of the 180-day-old animals CF = 6.70, P < 0.0051,differences being established between the ethanol-treated mice and the other three groups (Fig. 21. Both PTU- and PTU + ethanol-treated animals showed liver iron contents practically identical with those of the controls. With respect to liver copper, ethanol-treated animals showed higher concentrations than the
IO0 days
h5
140
Control group; - - Liver iron content. Fig. 1. Ethanol-treated group; . . -. - PTU-treated group; - * - * PTU + ethanol-treated group.
controls, but differences between the four groups were not statistically significant. However, the PTU + ethanol-treated animals showed liver copper levels very similar to those of the ethanol-treated mice.
’
1
Control group; Fig. 2. Liver copper content. -- Ethanol-treated group; * * * * * PTU-treated group; _._. - PTU + ethanol-treated group.
263
Discussion
Our results show that ethanol consumption is associated with an increase in liver iron content, a fact which is in accordance with other authors [5,6]. The underlying mechanism of ethanol-mediated iron overload still remains obscure. It has been proposed that the following may play a role: ethanol-mediated increased intestinal absorption [9]; increased absorption secondary to pancreatic damage [7]; increased uptake of transferrin-bound iron by the damaged liver [8]; favoured by the increased transferrin iron saturation [20,21] and increased availability of iron [22]. It is well known that hypothyroidism may reduce the absorption of iron [23]. This might explain our results concerning liver iron contents of the PTU + ethanol-treated animals. They could also be interpreted as the result of the general hypothyroid metabolic depression which could also affect liver iron uptake. PTU appears to counteract the effect of ethanol with respect to iron overload, but not regarding liver copper content. The liver regulates copper stores maintaining a highly efficient balance between albumin-bound copper uptake, biliary excretion and synthesis of plasma and tissue copper proteins [12]. In alcoholic cirrhosis high liver copper contents have been described [24], possibly as a result of impaired biliary excretion as well as decreased synthesis of copper protein. Hypothyroidism may reduce bile flow [25] and could thus affect the hepatic copper content, but this as well as a reduced uptake remains speculative. Nevertheless, our results demonstrate that PTU reverts the effect of ethanol on hepatic iron overload, a fact which is in accordance with the
protective role of this drug in ethanol-mediated liver injury. References 1 2 3 4
5 6 7 8 9 10 11 12 13
14 15 16 17 18 19 20 21 22 23
24 25
M. Rojkind and M.A. Dunn, Gastroenterology, ‘76 (19791849. H. Anttinen et al., Gastroenterology, 86 (19841532. E.J. Underwood, Trace Elements in Human and Animal Nutrition. Academic Press, New York, 1977. J.T. Galambos, Cirrhosis. In: L.H. Smith (Ed.), Major Problems in Internal Medicine, Vol. XVII, Saunders, Philadelphia, 1979. R.W. Chapman et al., Dig. Dis. Sci., 27 (19821909. P. Brissot et al., Gastroenterology, 80 (19811557. S. Sherlock, Diseases of the liver and Biliary system. Blackwell, Oxford, 1981. R.W. Chapman et al., Gastroenterology, 84 (19831143. R.W. Charlton et al., Br. Med. J., 2 (196411427. U. Mack et al., J. Biol. Chem., 258 (198314672. P.C. Adams et al., Hepatology, 8 (19881719. I. Sternlieb, Gastroenterology, 78 (198011615. N.W. Solomons. Zinc and copper in hepatobiliary and pancreatic disorders, In: Z.A. Karcioglu and R.M. Sarper (Eds.1, Zinc and Copper in Medicine, Charles C. Thomas, Springfield, 1980. H. Orrego et al., Gastroenterology, 76 (19791105. P. Hall& et al., Gastroenterology, 82 (19821925. H. Orrego et al., N. Eng. J. Med., 317 098711421. C.S. Lieber, N. Eng. J. Med., 319 (198811639. C.S. Lieber, Hepatology, 4 (1984) 1243. E. Gonzalez-Reimers et al., Drug Alcohol Depend, 21 (1988111. J. Lindenbaum and C.S. Lieber, N. Eng. J. Med., 281 (19691333. M.S. Wheby and L.G. Jones, J. Clin. Invest., 42 (19631 1007. MS. Wheby and G. Umpiere N. Eng. J. Med., 271 (19641 1391. S.H. Ingbar and K.A. Woeber, The thyroid gland. In: H. Williams (Ed.), Textbook of Endocrinology, Saunders, Philadelphia, 1975. S. Ritland et al., &and. J. Gastroenterol., 12 (1977) 81. K.E. Anderson and A. Kappas, Hormones and liver function. In: L. Schiff and E.R. Schiff (Eds.1, Diseases of the liver and biliary system, Lippincott, Philadelphia, 1982.