1144
Specialia
Effect of!cadmium~_~ on ,~tp~176176
EXPERIENTIA 33/9
. s .t r u.c t u. re . and . .f u n. ct ion . in ~nouse/Hver
S. G a m u l i n , N . C a r a n d P . N a r a n c s i k l
Institute o/Pathological Physiology, Medical Faculty, University o/Zagreb, KiYpatideva 12, 41000 Zagreb (Yugoslavia), 31 March 1977 Summary. C a d m i u m c h l o r i d e i n j e c t e d t o m i c e (20 ~ m o l e s / k g ) p r o v o k e s i n t h e l i v e r s a d e g r a d a t i o n of p o l y r i b o s o m e s a n d d i m i n i s h e s t h e i r p r o t e i n s y n t h e t i c a b i l i t y m e a s u r e d i n v i t r o . CdC12 a d d e d in a f i n a l c o n c e n t r a t i o n s b e t w e e n 30 a n d 100 ~ M t o t h e p r o t e i n s y n t h e t i c cell-free s y s t e m d e r i v e d f r o m l i v e r s of c o n t r o l m i c e i n h i b i t s i t s a c t i v i t y . C a d m i u m is b e c o m i n g a n i n c r e a s i n g l y i m p o r t a n t e n v i r o n m e n t a l t o x i c a g e n t . I t p r o d u c e s a w i d e r a n g e of t o x i c eff e c t s ill m a n a n d a n i m a l 2-4. S o m e e f f e c t s of c a d m i u m o n protein and nucleic acid biosynthesis have been described r e c e n t l y . A f t e r a d m i n i s t r a t i o n of c a d m i u m , c a d m i u m b i n d i n g p r o t e i n a p p e a r s i n t h e c y t o s o l of r a t liver, a n d it is proposed that cadmium induces its synthesis, stimulating s p e c i f i c m R N A s y n t h e s i s 5, 8. A t t h e s a m e t i m e , c a d m i u m inhibits temporarily the overall RNA-polymerase activity a n d d i m i n i s h e s t h e i n c o r p o r a t i o n of a r a d i o a c t i v e l y la-
4/ 0.5
b e l i e d a m i n o a c i d i n t o l i v e r p r o t e i n s 7. I n p a r t i a l l y h e p a t e c t o m i z e d r a t s , c a d m i u m d e c r e a s e s D N A s y n t h e s i s s. M o s t c o n d i t i o n s i n w h i c h t h e r a t e of p r o t e i n s y n t h e s i s is d e c r e a s e d a r e a c c o m p a n i e d b y a d i s a g g r e g a t i o n of p o l y r i b o s o m e s a n d b y a n i n c r e a s e i n t h e p r o p o r t i o n of m o n o m e r i c r i b o s o m e s in t h e t o t a l r i b o s o m a l p o p u l a t i o n of t h e cell". I n t h i s p a p e r w e s h a l l p r e s e n t a s i m i l a r e f f e c t p r o voked by cadmium in mouse liver. Materials and methods. M a l e a l b i n o m i c e w e i g h i n g 2 5 - 3 0 g maintained on standard 'Pliva-Zagreb' diet ad libitum were used. The polyribosome fraction and cytosol were i s o l a t e d f r o m p o o l e d l i v e r s of 3 m i c e a s d e s c r i b e d p r e v i o u s l y 10 u s i n g t h e a - a m y l a s e t r e a t m e n t of p o s t m i t o c h o n d r i a l s u p e r n a t a n t f o r i s o l a t i o n of p o l y r i b o s o m e s . I n t h e present work, 'Boehringer' ~-amylase was used.
0.4
~" 0.3
1
0.2
01
2
0 0.2
3 4 5
0.1
6
Y.
i
10 '
1'2 '
7
i
14cm 8
Radius Fig. 1. Sedimentation pattern of polyribosome fraction isolated from livers of a cadmium-treated and b control mice. The treated mice were injected i.p. with CdC12, 20 Exmoles/kg 1 h before killing. In three separate experiments similar results were obtained.
120
9 10
Acknowledgments. We are grateful to Prof. P. Sokolid for helpful discussion. The work was supported by Wellcome Trust grant and by a gift of chemicals from Kemika, Zagreb. We are grateful to both these organizations. H.M. Perry, Jr, G. S. Thind and E. F. Perry, Med. Clin. N. Am. 60, 759 (1976). M. Webb, Br. med. Bull. 31, 246 (1976). G.C. Becking, Med. Clins N. Am. 60, 813 (1976). K . S . Squibb and R. J. Cousins, Envir. Physiol. Biochem. d, 24 (1974). S . E . Bryan and H. A. Hidalgo, Biochem. biophys. Res. Commun. 68, 858 (1976). H . A . Hidalgo, V. Koppy and S. E. Bryan, FEBS Lett. 6,t, 159 (1976). R . E . Stoll, J. F. White, T. S. Miya and W. F. Bousquet, Toxic. appl. Pharmac. 37, 61 (1976). G. Vassart, J. E. Dumont and F. R. L. Cantraine, Bioehim. biophys. Acta 247, 471 (1971). S. Gamulin, C. H. Gray and M. R. Norman, Biochim. biophys. Acta 259, 239 (1972).
Protein synthesis in cell4ree systems derived from the livers of cadmium-treated and control mice
100~
Specialia
Effect of!cadmium~_~ on ,~tp~176176
EXPERIENTIA 33/9
. s .t r u.c t u. re . and . .f u n. ct ion . in ~nouse/Hver
S. G a m u l i n , N . C a r a n d P . N a r a n c s i k l
Institute o/Pathological Physiology, Medical Faculty, University o/Zagreb, KiYpatideva 12, 41000 Zagreb (Yugoslavia), 31 March 1977 Summary. C a d m i u m c h l o r i d e i n j e c t e d t o m i c e (20 ~ m o l e s / k g ) p r o v o k e s i n t h e l i v e r s a d e g r a d a t i o n of p o l y r i b o s o m e s a n d d i m i n i s h e s t h e i r p r o t e i n s y n t h e t i c a b i l i t y m e a s u r e d i n v i t r o . CdC12 a d d e d in a f i n a l c o n c e n t r a t i o n s b e t w e e n 30 a n d 100 ~ M t o t h e p r o t e i n s y n t h e t i c cell-free s y s t e m d e r i v e d f r o m l i v e r s of c o n t r o l m i c e i n h i b i t s i t s a c t i v i t y . C a d m i u m is b e c o m i n g a n i n c r e a s i n g l y i m p o r t a n t e n v i r o n m e n t a l t o x i c a g e n t . I t p r o d u c e s a w i d e r a n g e of t o x i c eff e c t s ill m a n a n d a n i m a l 2-4. S o m e e f f e c t s of c a d m i u m o n protein and nucleic acid biosynthesis have been described r e c e n t l y . A f t e r a d m i n i s t r a t i o n of c a d m i u m , c a d m i u m b i n d i n g p r o t e i n a p p e a r s i n t h e c y t o s o l of r a t liver, a n d it is proposed that cadmium induces its synthesis, stimulating s p e c i f i c m R N A s y n t h e s i s 5, 8. A t t h e s a m e t i m e , c a d m i u m inhibits temporarily the overall RNA-polymerase activity a n d d i m i n i s h e s t h e i n c o r p o r a t i o n of a r a d i o a c t i v e l y la-
4/ 0.5
b e l i e d a m i n o a c i d i n t o l i v e r p r o t e i n s 7. I n p a r t i a l l y h e p a t e c t o m i z e d r a t s , c a d m i u m d e c r e a s e s D N A s y n t h e s i s s. M o s t c o n d i t i o n s i n w h i c h t h e r a t e of p r o t e i n s y n t h e s i s is d e c r e a s e d a r e a c c o m p a n i e d b y a d i s a g g r e g a t i o n of p o l y r i b o s o m e s a n d b y a n i n c r e a s e i n t h e p r o p o r t i o n of m o n o m e r i c r i b o s o m e s in t h e t o t a l r i b o s o m a l p o p u l a t i o n of t h e cell". I n t h i s p a p e r w e s h a l l p r e s e n t a s i m i l a r e f f e c t p r o voked by cadmium in mouse liver. Materials and methods. M a l e a l b i n o m i c e w e i g h i n g 2 5 - 3 0 g maintained on standard 'Pliva-Zagreb' diet ad libitum were used. The polyribosome fraction and cytosol were i s o l a t e d f r o m p o o l e d l i v e r s of 3 m i c e a s d e s c r i b e d p r e v i o u s l y 10 u s i n g t h e a - a m y l a s e t r e a t m e n t of p o s t m i t o c h o n d r i a l s u p e r n a t a n t f o r i s o l a t i o n of p o l y r i b o s o m e s . I n t h e present work, 'Boehringer' ~-amylase was used.
0.4
~" 0.3
1
0.2
01
2
0 0.2
3 4 5
0.1
6
Y.
i
10 '
1'2 '
7
i
14cm 8
Radius Fig. 1. Sedimentation pattern of polyribosome fraction isolated from livers of a cadmium-treated and b control mice. The treated mice were injected i.p. with CdC12, 20 Exmoles/kg 1 h before killing. In three separate experiments similar results were obtained.
120
9 10
Acknowledgments. We are grateful to Prof. P. Sokolid for helpful discussion. The work was supported by Wellcome Trust grant and by a gift of chemicals from Kemika, Zagreb. We are grateful to both these organizations. H.M. Perry, Jr, G. S. Thind and E. F. Perry, Med. Clin. N. Am. 60, 759 (1976). M. Webb, Br. med. Bull. 31, 246 (1976). G.C. Becking, Med. Clins N. Am. 60, 813 (1976). K . S . Squibb and R. J. Cousins, Envir. Physiol. Biochem. d, 24 (1974). S . E . Bryan and H. A. Hidalgo, Biochem. biophys. Res. Commun. 68, 858 (1976). H . A . Hidalgo, V. Koppy and S. E. Bryan, FEBS Lett. 6,t, 159 (1976). R . E . Stoll, J. F. White, T. S. Miya and W. F. Bousquet, Toxic. appl. Pharmac. 37, 61 (1976). G. Vassart, J. E. Dumont and F. R. L. Cantraine, Bioehim. biophys. Acta 247, 471 (1971). S. Gamulin, C. H. Gray and M. R. Norman, Biochim. biophys. Acta 259, 239 (1972).
Protein synthesis in cell4ree systems derived from the livers of cadmium-treated and control mice
100~
