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P-207 Effect of interferon on the synthesis of lipids and apolipoproteins in HEPG2 cells
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Posters / International Hepatology Communications 3 Suppl. (1995) $37-S169
P-205 IRON DEPLETION BY FEEDING WITH IRONDEFICIENT DIET PREVENTS THE DEVELOPMENT OF LIVER CANCER IN LEC RATS M. Kobune 1, J. Kato 1, N. Sugawara 2, S. Katsuki 1, Y. Kohgo 3, Y. Niitsu.l 14th Dept. of Internal Medicine, 2Dept. of Public Health, Sapporo Medical University School of Medicine, Sapporo and 33rd Dept. of Internal Medicine, Asahikawa Medical College, Asahikawa, Japan The LEC rat is a mutant strain displaying hereditary hepatitis and spontaneous liver cancer. LEC rats accumulate excess copper in the liver, but have decreased levels of serum ceruloplasmin activity, a clinical presentation similar to human Wilson's disease. Although copper accumulation is probably important for the development of liver injury in LEC rats, it is unclear why few patients with Wilson's disease develop liver cancer. We previously demonstrated that LEC rats harbored additional abnormality accumulating excess iron as much as copper in the liver. Furthermore, we showed that deprivation of iron prevented the development of fuiminant hepatitis in LEC rats by feeding of iron-deficient diet. In the present study, we evaluated the preventive effect of development of liver cancer in LEC rats by long-term feeding of the iron-deficient diet. Either an iron-deficient diet (ID) or a regular diet (RD; same constitution as is except iron content) was fed to male LEC rats since 6-weeks after birth. LEC rats fed with ID showed markedly low levels of the hepatic iron comparing to RD fed LEC rats after 7-weeks until 65-weeks after birth. However, no differences in the hepatic copper levels were observed between ID and RD fed LEC rats during the same period. Histologicalexamination revealed that degree of both iron deposition and fibrosis in the liver of ID fed LEC rats were far less than that of RD fed rats in chronic hepatitis phase (32-weeks after birth). At the age of 65-weeks, all rats in RD group developed liver cancer, and the average weight of each liver obtained from LEC rats was 12.2 g. In contrast, none of LEC rats fed with ID developed liver cancer, and the average of the liver weight was 4.7 g. These results suggest that the accumulated excess iron in the liver play an important role on the development of liver cancer in LEC rats.
P-207 EFFECT OF INTERFERON ON THE SYNTHESIS OF LIPIDS AND APOLIPOPROTEINS IN HEPG2 CELLS. N . S h i m a z u , M . W a k a s h i m a , K.Nakata, K . K a n e k o , M . K i n o s h i t a , K . M i y a k e , T.Teramoto, M . Y a m a n a k a 1st Dept. o f I n t e r n a l M e d i c i n e , T e i k y o U n i v e r s i t y S c h o o l o f M e d i c i n e , Tokyo, , J a p a n
P-206 EFFECTS OF TRYPTOPHAN METABOLITES ON LIVER INJURY K.Uesugil), Y.Nagamural), M.Itol), I.lshigurol), K.Saitoh2), and A.Noma2) 1)Fnjita Health University, 2)Gifu University We have reported that administration of tryptophan O'rp) usually cures hepatic injury caused by curbontetrachmlide but occasionally causes aggravation of it and the serum concentration of kynurenine (Kyn) in hepatic injured mouse increases even though the low activity of tryptophandioxygenase (FDO) in hepatic injury. V~ will discuss that the acceleration of Kyn generation would be caused by macrophage and some Trp metabolites may play an important ro!e in both the cure of hepatie injury or aggravation of it. Mouse hepatic injury caused by a low concenlration of carbon tetrachloride was restrained by administration of Trp and serum Kyn concentration of hepatic injured mouse rose to about 4 times that of the control while, TDO activity of injured liver tissue was a quarter that of the control one. Liver injury after restriction of macrophage activity by intravenous injection of carbon particles became worse and the serum Kyn concentration in those mice was about three limes lower than that in control ones. On the other hand, hepatic injury caused by a high concentration of carbontetrachloride became worse by administration of Trp and the 3hydroxyanthranUicacid(3OHAmh) concentration in serum of injured mouse rose to about 5 times that of the control. Then, we examined what kind of influence Trp metabolites formed by macrophage have for hepatic injury both in vivo and in vitro. Trp metabolites were administraled to liver injured mice. Kyn and 3-hydroxykynurenine (3OKyn) depressed hepatic injury due to carbontetrachloride, but 3OHAnth, anthranilic add (Anth), kynurenic acid(KA )and quinolinic acid(QA) made it worse.The same phenomena were observed with experiments of isolated hepalocytes.
P-208
REGULATION OF THE VALINE CATABOLISM IN
HUMAN LIVER: COMPARISON BETWEEN NORMAL LIVER AND CIRRHOTIC LIVER K. Taniguchi~h T. Nonami ~), A. Nakao n, A. Harada,, T. Kurokawa~k Y. Shimomura 2), H. TakagiO Dept. of Surgery II, Nagoya Univ. School of Medicineo Dept. of Bioscience, Nagoya Inst. of Technology 2) Nagoya, Japan
A i m and Methods; We r e p o r t e d p r e v i o u s l y t h a t h y p e r triglyceridemia and hypo HDL-cholesterolemia were observed in interferon(IFN)-treatment of chronic h e p a t i t i s C. To e x p l o r e t h e m e c h a n i s m o f s u c h d y s l i p i d e m i a i n d u c e d b y IFN, w e s t u d i e d t h e e f f e c t o f IFN o n h e p a t i c s y n t h e s i s o f l i p i d s a n d a p o l i p o p r o t e i n s w i t h u s e o f HepG2 c e l l s . R e c o m b i n a n t IFN a 2a w a s a d d e d to t h e m e d i u m o f HepG2 c e i l s at t h e c o n c e n t r a t i o n o f 7900 U / m l . T h e s y n t h e t i c r a t e o f l i p i d s a n d apolipoproteins were monitored by incorporation of -~H-glycerol and -~sS-methionine, respectively. Results; T h e s y n t h e t i c r a t e s o f trigl3 c e r i d e ( T G ) a n d p h o s p h o l i p i d w e r e s i g n i f i c a n t l y l o w e r i n t h e IFNt r e a t e d c e l l s t h a n i n t h e c o n t r o l . T h a t o f apo A - I w a s extremely decreased, though that of albumin was not a f f e c t e d b y IFN. Conclusions; H y p e r t r i g l y c e r i d e m i a o b s e r v e d i n IFNt r e a t m e n t is n o t d u e to h e p a t i c o v e r p r o d u c t i o n o f TG, b u t m a y b e d u e to s u p p r e s s i o n o f l i p o p r o t e i n l i p a s e as r e p o r t e d p r e v i o u s l y . On t h e o t h e r h a n d , h y p o HDLc h o l e s t e r o l e m i a i n d u c e d b y IFN is p a r t l y d u e to s u p p r e s s i o n o f h e p a t i c s y n t h e s i s o f apo A-I, w h i c h is a m a j o r a p o l i p o p r o t e i n o f HDL.
Branched-chain amino acids(BCAAs) are often used to treat the patients with hepatic encephalopathy. In the catabolism of BCAAs, branched-chain ~ - k e t o acid d e h y d r o g e n a s e c o m p l e x ( B C K D C ) catalyzes o x i d a t i v e d e c a r b o x y l a t i o n of branched-chain ct-keto acids, which is the rate-limiting step in the pathway. Recently a unique feature of valine catabolism became evident; methacrylyl-CoA(MC-CoA), a toxic compound, was formed in the pathway and was catabolized and detoxified by MC-CoA hydratase(crotonase) and 3h y d r o x y i s o b u t y l y l - C o A ( H I B - C o A ) hydrolase. In the present study, we measured the activities of BCKDC, crotonase, and HIB-CoA hydrolase in human normal and cirrhotic livers, to investigate the effect of liver cirrhosis on the valine catabolism. The total activity of BCKDC was 16 + 4 mU/g wet wt. and was extremely low compared to that in normal rat liver, suggesting that liver was not the main organ for BCKA metabolism in human. Crotonase and HIB-CoA hydrolase activities were 12.3 + 2.5 U/g wet wt. and 7.3 + 1.1, respectively, in normal liver and 9.0 + 2.4 U/g wet wt. and 4.1 + 0.6 in cirrhotic liver. The activity of HIB-CoA hydrolase in cirrhotic l i v e r was significantly l o w e r than that in normal liver. This fact suggests the possibility of cell injury caused by MC-CoA in cirrhotic liver.
Posters / International Hepatology Communications 3 Suppl. (1995) $37-S169
P-205 IRON DEPLETION BY FEEDING WITH IRONDEFICIENT DIET PREVENTS THE DEVELOPMENT OF LIVER CANCER IN LEC RATS M. Kobune 1, J. Kato 1, N. Sugawara 2, S. Katsuki 1, Y. Kohgo 3, Y. Niitsu.l 14th Dept. of Internal Medicine, 2Dept. of Public Health, Sapporo Medical University School of Medicine, Sapporo and 33rd Dept. of Internal Medicine, Asahikawa Medical College, Asahikawa, Japan The LEC rat is a mutant strain displaying hereditary hepatitis and spontaneous liver cancer. LEC rats accumulate excess copper in the liver, but have decreased levels of serum ceruloplasmin activity, a clinical presentation similar to human Wilson's disease. Although copper accumulation is probably important for the development of liver injury in LEC rats, it is unclear why few patients with Wilson's disease develop liver cancer. We previously demonstrated that LEC rats harbored additional abnormality accumulating excess iron as much as copper in the liver. Furthermore, we showed that deprivation of iron prevented the development of fuiminant hepatitis in LEC rats by feeding of iron-deficient diet. In the present study, we evaluated the preventive effect of development of liver cancer in LEC rats by long-term feeding of the iron-deficient diet. Either an iron-deficient diet (ID) or a regular diet (RD; same constitution as is except iron content) was fed to male LEC rats since 6-weeks after birth. LEC rats fed with ID showed markedly low levels of the hepatic iron comparing to RD fed LEC rats after 7-weeks until 65-weeks after birth. However, no differences in the hepatic copper levels were observed between ID and RD fed LEC rats during the same period. Histologicalexamination revealed that degree of both iron deposition and fibrosis in the liver of ID fed LEC rats were far less than that of RD fed rats in chronic hepatitis phase (32-weeks after birth). At the age of 65-weeks, all rats in RD group developed liver cancer, and the average weight of each liver obtained from LEC rats was 12.2 g. In contrast, none of LEC rats fed with ID developed liver cancer, and the average of the liver weight was 4.7 g. These results suggest that the accumulated excess iron in the liver play an important role on the development of liver cancer in LEC rats.
P-207 EFFECT OF INTERFERON ON THE SYNTHESIS OF LIPIDS AND APOLIPOPROTEINS IN HEPG2 CELLS. N . S h i m a z u , M . W a k a s h i m a , K.Nakata, K . K a n e k o , M . K i n o s h i t a , K . M i y a k e , T.Teramoto, M . Y a m a n a k a 1st Dept. o f I n t e r n a l M e d i c i n e , T e i k y o U n i v e r s i t y S c h o o l o f M e d i c i n e , Tokyo, , J a p a n
P-206 EFFECTS OF TRYPTOPHAN METABOLITES ON LIVER INJURY K.Uesugil), Y.Nagamural), M.Itol), I.lshigurol), K.Saitoh2), and A.Noma2) 1)Fnjita Health University, 2)Gifu University We have reported that administration of tryptophan O'rp) usually cures hepatic injury caused by curbontetrachmlide but occasionally causes aggravation of it and the serum concentration of kynurenine (Kyn) in hepatic injured mouse increases even though the low activity of tryptophandioxygenase (FDO) in hepatic injury. V~ will discuss that the acceleration of Kyn generation would be caused by macrophage and some Trp metabolites may play an important ro!e in both the cure of hepatie injury or aggravation of it. Mouse hepatic injury caused by a low concenlration of carbon tetrachloride was restrained by administration of Trp and serum Kyn concentration of hepatic injured mouse rose to about 4 times that of the control while, TDO activity of injured liver tissue was a quarter that of the control one. Liver injury after restriction of macrophage activity by intravenous injection of carbon particles became worse and the serum Kyn concentration in those mice was about three limes lower than that in control ones. On the other hand, hepatic injury caused by a high concentration of carbontetrachloride became worse by administration of Trp and the 3hydroxyanthranUicacid(3OHAmh) concentration in serum of injured mouse rose to about 5 times that of the control. Then, we examined what kind of influence Trp metabolites formed by macrophage have for hepatic injury both in vivo and in vitro. Trp metabolites were administraled to liver injured mice. Kyn and 3-hydroxykynurenine (3OKyn) depressed hepatic injury due to carbontetrachloride, but 3OHAnth, anthranilic add (Anth), kynurenic acid(KA )and quinolinic acid(QA) made it worse.The same phenomena were observed with experiments of isolated hepalocytes.
P-208
REGULATION OF THE VALINE CATABOLISM IN
HUMAN LIVER: COMPARISON BETWEEN NORMAL LIVER AND CIRRHOTIC LIVER K. Taniguchi~h T. Nonami ~), A. Nakao n, A. Harada,, T. Kurokawa~k Y. Shimomura 2), H. TakagiO Dept. of Surgery II, Nagoya Univ. School of Medicineo Dept. of Bioscience, Nagoya Inst. of Technology 2) Nagoya, Japan
A i m and Methods; We r e p o r t e d p r e v i o u s l y t h a t h y p e r triglyceridemia and hypo HDL-cholesterolemia were observed in interferon(IFN)-treatment of chronic h e p a t i t i s C. To e x p l o r e t h e m e c h a n i s m o f s u c h d y s l i p i d e m i a i n d u c e d b y IFN, w e s t u d i e d t h e e f f e c t o f IFN o n h e p a t i c s y n t h e s i s o f l i p i d s a n d a p o l i p o p r o t e i n s w i t h u s e o f HepG2 c e l l s . R e c o m b i n a n t IFN a 2a w a s a d d e d to t h e m e d i u m o f HepG2 c e i l s at t h e c o n c e n t r a t i o n o f 7900 U / m l . T h e s y n t h e t i c r a t e o f l i p i d s a n d apolipoproteins were monitored by incorporation of -~H-glycerol and -~sS-methionine, respectively. Results; T h e s y n t h e t i c r a t e s o f trigl3 c e r i d e ( T G ) a n d p h o s p h o l i p i d w e r e s i g n i f i c a n t l y l o w e r i n t h e IFNt r e a t e d c e l l s t h a n i n t h e c o n t r o l . T h a t o f apo A - I w a s extremely decreased, though that of albumin was not a f f e c t e d b y IFN. Conclusions; H y p e r t r i g l y c e r i d e m i a o b s e r v e d i n IFNt r e a t m e n t is n o t d u e to h e p a t i c o v e r p r o d u c t i o n o f TG, b u t m a y b e d u e to s u p p r e s s i o n o f l i p o p r o t e i n l i p a s e as r e p o r t e d p r e v i o u s l y . On t h e o t h e r h a n d , h y p o HDLc h o l e s t e r o l e m i a i n d u c e d b y IFN is p a r t l y d u e to s u p p r e s s i o n o f h e p a t i c s y n t h e s i s o f apo A-I, w h i c h is a m a j o r a p o l i p o p r o t e i n o f HDL.
Branched-chain amino acids(BCAAs) are often used to treat the patients with hepatic encephalopathy. In the catabolism of BCAAs, branched-chain ~ - k e t o acid d e h y d r o g e n a s e c o m p l e x ( B C K D C ) catalyzes o x i d a t i v e d e c a r b o x y l a t i o n of branched-chain ct-keto acids, which is the rate-limiting step in the pathway. Recently a unique feature of valine catabolism became evident; methacrylyl-CoA(MC-CoA), a toxic compound, was formed in the pathway and was catabolized and detoxified by MC-CoA hydratase(crotonase) and 3h y d r o x y i s o b u t y l y l - C o A ( H I B - C o A ) hydrolase. In the present study, we measured the activities of BCKDC, crotonase, and HIB-CoA hydrolase in human normal and cirrhotic livers, to investigate the effect of liver cirrhosis on the valine catabolism. The total activity of BCKDC was 16 + 4 mU/g wet wt. and was extremely low compared to that in normal rat liver, suggesting that liver was not the main organ for BCKA metabolism in human. Crotonase and HIB-CoA hydrolase activities were 12.3 + 2.5 U/g wet wt. and 7.3 + 1.1, respectively, in normal liver and 9.0 + 2.4 U/g wet wt. and 4.1 + 0.6 in cirrhotic liver. The activity of HIB-CoA hydrolase in cirrhotic l i v e r was significantly l o w e r than that in normal liver. This fact suggests the possibility of cell injury caused by MC-CoA in cirrhotic liver.