Circadian clocks regulate the temporal organization of several biochemical processes, including lipid metabolism, and their disruption leads to severe metabolic disorders. Immortalized cell lines acting as circadian clocks display daily variations in [(32)P]phospholipid labeling; however, the regulation of glycerophospholipid (GPL) synthesis by internal clocks remains unknown. Here we found tha...

Diacylglycerol pyrophosphate (DGPP) is involved in a putative novel lipid signaling pathway. DGPP phosphatase (DGPP phosphohydrolase) is a membrane-associated 34-kDa enzyme from Saccharomyces cerevisiae which catalyzes the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyzes the dephosphorylation of PA to yield diacylglycerol. Amino acid sequence information derived from DGP...

The specific activity of phosphatidate phosphohydrolase (PAPase) (EC 3.1.3.4) has been assayed in organotypic cultures of foetal rat lung type II alveolar pneumonocytes and in L2 cells derived from type II cells of the adult rat lung. This enzyme catalyses a critical step in the synthesis of phosphatidylcholine, the major lipid component of pulmonary surfactant. Surfactant is produced by the ma...

The choline-deficient rat liver has been chosen as a physiologically relevant model system in which to study the regulation of phosphatidylcholine biosynthesis. When 50-g rats were placed on a choline-deficient diet for 3 days, the activity of CTP:phosphocholine cytidylyltransferase (CT) was increased 2-fold in the microsomes and decreased proportionately in the cytosol. A low titer antibody to...

Diacylglycerol was generated in vitro in rat lung microsomes by forming phosphatidic acid via sn-glycerol-3-phosphate acyltransferase followed by the hydrolysis of the phosphatidic acid by phosphatidate phosphohydrolase. Diacylglycerol concentrations of 35 to 50 nmol/mg of microsomal protein were obtained. Cholinephosphotransferase activity was determined in microsomes by measuring the conversi...

The superoxide-generating neutrophil NADPH oxidase can be activated in cell-free reconstitution systems by several agonists, most notably arachidonic acid and the detergent sodium dodecyl sulfate. In this study, we show that both phosphatidic acids and diacylglycerols can serve separately as potent, physiologic activators of NADPH oxidase in a cell-free system. Stimulation of superoxide generat...

Partially hepatectomized rats were used to investigate the mechanism of fatty-liver development in the regenerating rat liver. After partial hepatectomy the amount of hepatic triacylglycerol increased by almost 4-fold compared with sham-operated rats. The activities of both cytosolic and microsomal phosphatidate phosphohydrolase were enhanced at 12 h after surgery. The activity of diacylglycero...

The present study was conducted to elucidate the metabolic pathways by which enlarged liver size of patients undergoing disorders of orotic acid de novo metabolism and those patients of enlarged liver size induced by di(2-ethyl hexyl) phthalate in rats as animal model. The results showed that rats-treated with orotic acid generated liver triglyceride content 400% higher than that of the control...

The aim of the paper was to study the effect of carbisocaine, a new local anesthetic with high liposolubility on incorporation of 32P into individual and total phospholipids and to compare its effect with that of other local anesthetics (procaine, lidocaine, cinchocaine, heptacaine). Carbisocaine decreased 32P incorporation into neutral phospholipids and increased the incorporation into acid ph...

The sequence of reactions which function to incorporate choline into phosphatidylcholine was investigated in lung from fetuses following premature delivery. The rate of [methyl-14C]choline incorporation by rat lung slices into phosphatidylcholine increases following premature delivery at both 20 and 21 days gestation. The increase in choline incorporation is primarily due to an increased specif...