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Biomedical subjects

G Goracci

Publications and source records attributed to G Goracci.

At least 91 records · Page 5Linked to original sources

The reverse reaction of cholinephosphotransferase in rat brain microsomes. A new pathway for degradation of phosphatidylcholine.

The synthesis of phosphatidylcholine is catalyzed by cholinephosphotransferase (EC 2.7.8.2) which is known to be reversible in liver. The reversibility of cholinephosphotransferase in rat brain in demonstrated in this paper. Labeled microsomes were prepared from young rats which had been given an intracerebral injection of labeled choline or oleate 2 h before killing. During incubation of choline-labeled microsomes with CMP, label was lost from ;choline glycerophospholipids and labeled CDPcholine was produced. The Km for CMP was 0.35 mM and V was 3.3 nmol/min per mg protein. Neither AMP nor UMP could substitute for CMP. Oleate-labeled microsomes were pretreated with e mM diisopropylfluorophosphate (lipase inhibitor). During incubation with CMP, label was lost from choline, and ethanolamine glycerophospholipid and labeled diacylglycerols were produced. When the lipase was not inhibited, labeled oleate was produced. We propose that a principal pathway for degradation of phosphatidylcholine, particularly during brain ischemia, is by reversal of cholinephosphotransferase, followed by hydrolysis of diacylglycerols by the lipase.

Animals↗

Glycerophospholipid metabolism in neuronal and glial cell-enriched fractions.

The metabolism of phospholipids in separated glial and neuronal cells has been reviewed in this paper. Lipids are more abundant in glia; on the other hand, in vivo experiments performed with labeled precursors have indicated that lipid turnover is faster in neurons (with the possible exception of oligodendroglia). Biosynthetic and catabolic enzymes of lipid metabolism have been studied in separated cells (mainly in neurons and astroglia) and have been shown to be almost always more active in neurons. Also base exchange is probably more active in these cells. Therefore the results of in vitro and in vivo experiments indicate that neurons are more active than astroglia in metabolizing glycerophospholipids.

Aging↗