Download cholesterol and triacylglycerol concentrations in blood serum

TUESDAY 31 M A R C H
POSTERS RELATED TO S12
Tue-S12-22
Tue-S12-23
PLASMA LDL AND HDL I N RATS W I T H NEPHROTIC
SYNDROME.
S. C a l a n d r a & E . G h e r a r d i , I n s t i t u t e o f P a t h o l o g y , U n i v e r s i t y o f Modena,
41100, Modena, V i a C a m p i 2 8 7 ( I t a l y ) .
I n c o n t r o l r a t s LDL(concentration:26+5mg/l
w e r e homogeneous i n p r e p a r a t i v e a g a r o s e g e l
e l e c t r o p h o r e s i s ( A G E ) and c o n t a i n e d m o s t l y
ApoB. H D L 1 ( 2 1 + 3 m g / l ) w e r e s e p a r a t e d i n t o 2
f r a c t i o n s : p ( 6 0 % ) a n d a2(40%). The p c o n t a i
n e d ApoB; a2 c o n t a i n e d ApoE. HDL2(179+17mgd
w e r e homogeneous i n AGE. I n N e p h r o t i c r a t s
LDL(140+13mg/l) were s e p a r a t e d i n t o P (85%)
a n d a a f r a c t i o n ( l 5 % ) . P c o n t a i n e d ApoB; a 2
c o n t a i n e d ApoE a n d A p o A I . H D L l (315+31mglD
were s e p a r a t e d i n t o p (25%) and a f r a c t i o n
( 7 5 % ) . p c o n t a i n e d ApoB; a c o n t a i n e d A p o A I ,
ApoE a n d C. HDL2 (585+8Qmg/1) c o n t a i n e d
A p o A I b u t l e s s A p o A I V a n d ApoE, t h a n c o n t r o l HDL
T h e r e f o r e an A p o A I r i c h HDL a c c u
2'
m u l a t e s i n plasma o f n e p h r o t i c r a t s .
METABOLISM OF CHYLOMICRON PHOSPHATIDYLCHOLINE AND
PHOSPHATIDYLETHANOLAMINE IN THE RAT
When 32P-labelled lymph duct chylomicrons are injected intravenously into rats, the major part of
both [32P]phosphatidylcholine (PC) and [32P]phosphatidylethanolamine (PE) are rapidly and in parallel transferred to denser lipoproteins. After this
transfer the [32P]PE is, however, eliminated from
plasma and taken up in the liver at a significantly
faster rate than is the [32P]PC. In the hepatectomized rat the elimination of both hospholipids is
markedly decreased. Chylomicron [3qP]PE is taken up
faster than [32P]PC in the perfused rat liver but
not in isolated parenchymal or non-parenchymal
liver cells. Since the hepatic lipase is known to
exhibit greater activity against PE than PC i n
v i t r o , these data are compatible with an important
role for the hepatic lipase in the chylomicron
phospholipid metabolism.
Tue-S12-24
Tue-S12-25
Britta Larsson and Rke Nilsson
Department of Physiological Chemistry, University
of Lund, Lund, Sweden
: ON THE SYNTHESIS OF
ROLE OF MONOACYLGLYCEROL LIPASE IN ADIPOSE
TISSUE METABOLISM
Hans Tornqvist, Dept, of Clin, Chemistry, Malmij
General Hospital, S-21401 Malmii, Sweden
JVER.
t D.E.VANCE,
:hemistrv.Universitv of British Columbia.
Vancouver,B. C. ,Canada C 'NIh,Bethesda ,Md ,U. S A.
.,
Highly purified monoacylglycerol lipase (MGL)
from rat adipose tissue hydrolyses l(3)- and 2monoacylglycerols zit equal rates and lacks activity against other acylglycerols. The enzyme is
located in the adipocytes, but the subcellular
distribution is thus far not known. Compared to
the monoacylglycerol-hydrolyzing activities of
lipoprotein lipase (LPL) and hormone-sensitive
lipas'e (HSL) it has a several-fold higher activity
in the tissue especially in the fasted state.
.
HSL catalyzed lipolysis of intracellularily stored
triacylglycerols and on the Z-monoacylglycerols
produced and possibly transported into the adipocytes as a result of LPL action on the incoming
plasma chylomicrons and/or VLDL particles.
Deasaadenosine(DZA) has been shown to inhibit the
synthesis of phosphatidylcholine(PC) by N-methylation of phosphatidlyethanolamine(PE) and to stimulate the incorporation of choline into PC via the
CDP-choline pathway in vivo. This effect was also
observed in rat hepatocytes maintained in monolayer culture. Pulse-chase studies with 3H-choline
and precursor pool size measurements showed that
DZA (13vM) in the culture medium caused a 5-fold
increase in the rate of PC biosynthesis despite
a 30% decrease in the cellular phosphocholine
levels. The mechanism by which DZA modifies the
activity of the CDP-choline pathway is not yet
clear but preliminary experiments suggest that
the effect is mediated by an increased activity of
CTP:phosphocholine cytidylyltransferase.
Tue-S12-26
Tue-S12-27
CHOLESTEROL AND TRIACYLGLYCEROL CONCENTRATIONS I N BLOOD SERUM LIPOPROTEIN FRACTIONS I N RABBITS WITH ACUTE
EXPERIMENTAL URAEMIA
-Lutz
*
W P Szeszko A . , JaBdBewski B.
I n s t i t u t e o f I n t e r n a l Medicine MMA,
Zddi, Poland
I n 15 r a b b i t s with acute uraemia,
induced by b i l a t e r a l u r e t e r li a t i o n ,
concentrations of c h o l e s t e r o l $CH/ and
t r i a c y l g l y c e r o l s /TG/ were determined
i n blood serum l i p o p r o t e i n f r a c t i o n s
VLDL, LDL and HDL, obtained w i t h doub l e p r e c i p i t a t i o n technique.
I t w a s found t h a t t h e increase i n
t o t a l serum TG concentration i n uraemic animals is due t o the increase i n
t h e i r content i n VLDL f r a c t i o n . The
decrease i n CH concentration i n HDL,
which concerned f r e e CH and i t s e s t e r s ,
had no s i g n i f i c a n t e f f e c t on t o t a l serum CH concentration.
FAmORS INFLUENCING THE RATE OF LIPOLYSIS BY
RHIZOPUS ARRHIZUS LIPASE
Iliano Luc, Goemaere Francine and Lauwers Albert
Lab. Bioch. Fac. Farm. Wet. R.U.G.,
Wolterslaan 12, 9000 Gent/BELGIUM.
The role of the enzyme might be to act on the
l(3)- or 2-monoacylglycerols produced during the
The particle size distribution of an olive oil/
water emulsion was determined by means of a Coulter Counter TAII, and correlated to the rate of
lipolysis by Rhizopus arrhizus lipase. Activity
measurements in function of different interfacial
areas/volume unit were performed, using the pHstat technique.
Lipolytic activities were dependent on the lowering of the interfacial tension by bile salts.
Measurements of these tensions were performed
at constant temperature by means of the drop
weight method. The influence of the concentration
of surface active agents on the rate of lipolysis
and on the interfacial tension of an olive oil/
water system was studied to correlate the lowering of the interfacial tension and the changes
in the rate of lipolysis observed.
185P