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Biomedical subjects

G Porcellati

Publications and source records attributed to G Porcellati.

At least 91 records · Page 5Linked to original sources
PubMed1977

The effect of silybin on liver phospholipid synthesis in the rat in vivo.

Female Wistar rats have been injected intravenously for seven days with various different doses of silybin, the main component of the drug silymarin, and the in vitro synthesis of phosphatidylethanolamine and phosphatidylcholine from their respective precursors, CDP-ethanolamine and CDP-choline has been examined in liver microsomal membranes. Appreciable inhibition of the incorporation rates of precursors into lipids has been noticed at dosage of 15-20 mg/100 g body wt., daily. No evident effect is exerted by similar silybin treatment on choline and ethanolamine incorporation respectively into liver phosphatidylcholine and phosphatidylethanolamine in vivo.

Animals↗
PubMed1977

The effect of acute ethanol administration on phosphorylethanolamine uptake and metabolism in rat liver slices.

Double-labelled phosphorylethanolamine with a [32P]//[14IA1 ratio of 1 was incubated in vitro with rat liver slices prepared from control and ethanol-intoxicated rats, and the radioactivity measured at given time intervals in liver ethanolamine, phosphorylethanolamine, phosphatidylethanolamine and phosphatidylcholine. Evidence is presented that after 10 and 15 minutes phosphorylethanolamine enters the slices as an intact molecule, which is directly converted into lipid forms by the Kennedy's pathways. At longer times a hydrolysis of the ester occurs which lowers considerably the theoretical [32P]/[14C]ratio. Fatty liver slices produced by acute ethanol intoxication uptake from the medium more phosphorylethanolamine than controls, and hydrolyze less efficiently than controls the phosphoric ester to ethanolamine and inorganic phosphate.

Animals↗
PubMed1976

Relationships between base-exchange reaction and the microsomal phospholipid pool in the rat brain in vitro.

The calcium-stimulated incorporation of ethanolamine, choline and L-serine into rat brain microsomal phospholipids has been investigated. The membranes were prelabeled in vitro in their choline or serine phosphoglycerides by base-exchange and then chasing experiments were done by displacing the lipid-bound base by ethanolamine, choline, or L-serine labeled with a different isotope. The results indicate that membrane phosphatidylcholine is presumably a substrate for the exchange with all the three bases, whereas phosphatidylserine exchanges only with ethanolamine and L-serine but not with choline. A small phospholipid pool (3-7% of the total available pool) is active in the calcium-dependent exchange with choline, ethanolamine, and L-serine. When the microsomal membranes are prelabeled in vitro in their phosphatidylcholine moiety through the cytidine-dependent pathway and then chasing experiments are performed with the three nitrogenous bases, as above, the small phospholipid pool is hardly detectable. In view of these and other results (Gaiti et al., FEBS Letters 49:361 1975), it is suggested that at least two different pools of phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine might exist in rat brain microsomes.

Animals↗
PubMed1976

The effect of egg phospholipid administration upon liver enzymic activities during ethionine treatment.

Female rats were injected subcutaneously with ethionine, and enzymic activities of liver membranes (Na+-k+-stimulated ATPase, Mg2+-stimulated ATPase, glucose-6-phosphatase, NADPH: cytochrome c oxido-reductase and NAD-nucleosidase) examined at proper intervals, during the intraperitoneal treatment of an egg phospholipid preparation (EPL). It is shown that EPL is unable to overcome the enzymic changes due to severe ethionine treatment, but is able to facilitate the recovery times after drug withdrawal for all the enzymic activities, except for NAD-nucleosidase. At lower dosage of the drug, the ethionine treatment is able to prevent the observed change of the glucose-6-phosphatase activity but not that of the Mg2+-ATPase. It is suggested that the EPL treatment may modify the chemical composition ahd/or architecture of liver membranes, altered by the ethionine injection, thus acting, at least partially, on the enzymic changes.

Adenosine Triphosphatases↗
PubMed1975

Enzymic synthesis of 1-alkyl-2-acyl-sn-glycero-3-phosphorylethanolamine through ethanolaminephosphotransferase activity in the neuronal and glial cells of rabbit in vitro.

The transfer of radioactivity from cytidine-5'-diphosphate ethanolamine into 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine of neuronal and glial cells from adult rabbit brain cortex has been investigated in vitro. The synthesis of 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine in both cell populations was stimulated 23-25-fold by the addition of 6 mM alkylacylglycerol. The neuronal cell-enriched fraction was found to possess/unit protein a 1.7-1.8-fold ethanolaminephosphotransferase activity (EC 2.7.8.1), as compared to the glial fraction, when saturating concentrations (6 mM) of alkylacylglycerols were added in the incubation system. The neuronal/glial ratio was 2.6-2.8 in the absence of lipid acceptor or with low concentrations of alkylacylglycerol. Under most favorable conditions, 6.4 and 3.3 nmoles 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine/mg protein/30 min was obtained for neurons and glia, respectively. Various kinetic properties of the 1-alkyl-2-acyl-sn-glycerophosphorylethanolamine synthesizing phosphotransferase activity were found to be similar both in neurons and glia.

Animals↗