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Brain microsomal galactosyltransferases. distinct enzymes for glycolipid and glycoprotein acceptor substrates
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125 EFFECT
OF H Y P O T H Y R O I D I S M ON THE L A B E L I N G OF THE VARIOUS RNA SPECIES IN D E V E L O P I N G RAT BRAIN. Serra I., *Renis M., Lombardo B., Ragonese P., Avola R., and Giuffrida A.M. (Institute of Biochemistry, University of Catania and *Mental Hospital of Bisceglie, Italy) The effect of h y p o t h y r o i d i s m on the in vitro i n c o r p o r a t i o n of 3H-uridine into d i f f e r e n t RNA species ~n tissue slices of rat cerebral h e m i s p h e res at 5, iO, 15 and 21 days of age was investigated. Gel e l e c t r o p h o r e t i c analysis of total, n u c l e a r and mlcrosomal RNA was also accomplished. The results o b t a i n e d indicate that RNA labeling is d i f f e r e n t l y influenced by h y p o t h y r o i d i s m at the various ages examined. RNA labeling is not significantly a f f e c t e d at 5 days of age while at later ages and e s p e c i a l l y at 21 days it is h i g h e r ~n h y p o t h y r o i d rats c o m p a r e d to the controls. Distinct d i f f e r e n c e s in the transport of newly s y n t h e s i z e d RNA from the nucleus to the c y t o p l a s m at the various ages examined ~n the two groups of animals were found. These results are in agreement with the h y p o t h e s i s that thyroid hormone d e f i c i e n c y causes a delay of the p r o c e s s e s of cell p r o l i f e r a t i o n and d i f f e r e n t i a t i o n in d e v e l o p i n g rat brain.
126
BRAIN MICROSOMAL GALACTOSYLTRANSFERASES. DISTINCT ENZYMES FOR GLYCOLIPID AND GLYCOPROTEIN ACCEPTOR SUBSTRATES. M. ~ERRE~-GUILLAUMOND, H. BAUBICHON-CORTAY, P. BROQUET.F. LERM~and P. LOUISOT University of Lyon INSERMU.189 and CNRS-ERA562, B.P. 12 69921 - OULLINS Cedex FRANCE Brain galactosyltransferase activity was investigated with respect to glycoproteinic and lipidic acceptors in order to point out their relative specificity. The galactosyltransferase activities are tightly related to the postnatal rat brain development. A maximal activity is respectively observed at 21 days for the glycolipid biosynthesis and from 35thto38 th days for the glycolipid and glycoproteinbiosynthesis. These data suggest the opportunity of several galactosyltransferases. Indeed the studies of their physical and chemical properties show a significant difference in their optimal activities. A competition between glycoproteinic and lipidic accepto~ is demonstrai~ed. Detergents and phospholipids interfere in a different way on galactosyltransferases with respect to glycoproteinic and lipidic acceptors.
1 2 7 C U L T U R E D O L I G O D E N D R O C Y T E S (ODC) - B U L K - I S O L A T E D F R O M A D U L T PIG BRAIN SYNTHESIZE AND RELEASE P R O S T A G L A N D I N S ( P G ) ~, SieD1. H.-H. A l t h a u s and V. N e u h o f f M a x - P l a n c k - I n s t i t u t fur e x p e r i m e n t e l l e Medizin,
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D-3400 G S t t i n g e n
During d e v e l o p m e n t of the central nervous system neural cells are g u i d e d and/or i n t e r a c t either by m e m b r a n e o u s c o n t a c t s or via i n f o r m a t i o n a l substances. It is u n k n o w n w h e t h e r PG p l a y a role in this concept and w h e t h e r o l i g o d e n d r o g l i a l cells can p r o d u c e PG. ODC are i ~ l a t e d from adult pig brain (I). W h e n 1 4 C - 8 , 1 1 , 1 4 - e i c o s a t { ~ e n o i c acid and C - a r a c h i d o n i c acid are given as precursors, ODC release Cp r o s t a g l a d i n s into the medium. This process can be m o d u l a t e d by e x t e r n a l ly a d m i n i s t e r e d PG or o t h e r m o d u l a t o r s . The action of PG on ODC is m e d i ated by c y c l i c - a d e n o s i n e m o n o p h o s p h a t e . I) P.J. G e b i c k e - H ~ r t e r , H.-H. Althaus, J. Neurochem., ~, 357-368 (1984).
I . R i t t n e r and V. Neuhoff.
125 EFFECT
OF H Y P O T H Y R O I D I S M ON THE L A B E L I N G OF THE VARIOUS RNA SPECIES IN D E V E L O P I N G RAT BRAIN. Serra I., *Renis M., Lombardo B., Ragonese P., Avola R., and Giuffrida A.M. (Institute of Biochemistry, University of Catania and *Mental Hospital of Bisceglie, Italy) The effect of h y p o t h y r o i d i s m on the in vitro i n c o r p o r a t i o n of 3H-uridine into d i f f e r e n t RNA species ~n tissue slices of rat cerebral h e m i s p h e res at 5, iO, 15 and 21 days of age was investigated. Gel e l e c t r o p h o r e t i c analysis of total, n u c l e a r and mlcrosomal RNA was also accomplished. The results o b t a i n e d indicate that RNA labeling is d i f f e r e n t l y influenced by h y p o t h y r o i d i s m at the various ages examined. RNA labeling is not significantly a f f e c t e d at 5 days of age while at later ages and e s p e c i a l l y at 21 days it is h i g h e r ~n h y p o t h y r o i d rats c o m p a r e d to the controls. Distinct d i f f e r e n c e s in the transport of newly s y n t h e s i z e d RNA from the nucleus to the c y t o p l a s m at the various ages examined ~n the two groups of animals were found. These results are in agreement with the h y p o t h e s i s that thyroid hormone d e f i c i e n c y causes a delay of the p r o c e s s e s of cell p r o l i f e r a t i o n and d i f f e r e n t i a t i o n in d e v e l o p i n g rat brain.
126
BRAIN MICROSOMAL GALACTOSYLTRANSFERASES. DISTINCT ENZYMES FOR GLYCOLIPID AND GLYCOPROTEIN ACCEPTOR SUBSTRATES. M. ~ERRE~-GUILLAUMOND, H. BAUBICHON-CORTAY, P. BROQUET.F. LERM~and P. LOUISOT University of Lyon INSERMU.189 and CNRS-ERA562, B.P. 12 69921 - OULLINS Cedex FRANCE Brain galactosyltransferase activity was investigated with respect to glycoproteinic and lipidic acceptors in order to point out their relative specificity. The galactosyltransferase activities are tightly related to the postnatal rat brain development. A maximal activity is respectively observed at 21 days for the glycolipid biosynthesis and from 35thto38 th days for the glycolipid and glycoproteinbiosynthesis. These data suggest the opportunity of several galactosyltransferases. Indeed the studies of their physical and chemical properties show a significant difference in their optimal activities. A competition between glycoproteinic and lipidic accepto~ is demonstrai~ed. Detergents and phospholipids interfere in a different way on galactosyltransferases with respect to glycoproteinic and lipidic acceptors.
1 2 7 C U L T U R E D O L I G O D E N D R O C Y T E S (ODC) - B U L K - I S O L A T E D F R O M A D U L T PIG BRAIN SYNTHESIZE AND RELEASE P R O S T A G L A N D I N S ( P G ) ~, SieD1. H.-H. A l t h a u s and V. N e u h o f f M a x - P l a n c k - I n s t i t u t fur e x p e r i m e n t e l l e Medizin,
-
D-3400 G S t t i n g e n
During d e v e l o p m e n t of the central nervous system neural cells are g u i d e d and/or i n t e r a c t either by m e m b r a n e o u s c o n t a c t s or via i n f o r m a t i o n a l substances. It is u n k n o w n w h e t h e r PG p l a y a role in this concept and w h e t h e r o l i g o d e n d r o g l i a l cells can p r o d u c e PG. ODC are i ~ l a t e d from adult pig brain (I). W h e n 1 4 C - 8 , 1 1 , 1 4 - e i c o s a t { ~ e n o i c acid and C - a r a c h i d o n i c acid are given as precursors, ODC release Cp r o s t a g l a d i n s into the medium. This process can be m o d u l a t e d by e x t e r n a l ly a d m i n i s t e r e d PG or o t h e r m o d u l a t o r s . The action of PG on ODC is m e d i ated by c y c l i c - a d e n o s i n e m o n o p h o s p h a t e . I) P.J. G e b i c k e - H ~ r t e r , H.-H. Althaus, J. Neurochem., ~, 357-368 (1984).
I . R i t t n e r and V. Neuhoff.