The present study demonstrates that the biosynthesis of phospholipids in the inner nuclear layer cells of the chicken retina displays daily rhythms under constant illumination conditions. The vertebrate retina contains circadian oscillators and photoreceptors (PRCs) that temporally regulate its own physiology and synchronize the whole organism to the daily environmental changes. We have previou...

The activities of nucleoside diphosphatases and thiamine pyrophosphatase (TPPase) that are associated with the Golgi apparatus and acid phosphatase were measured by quantita.. tive histochemical methods both in histologically pure nucleus supraopticus and in an adjacent area of the anterior hypothalamus of the rat. In the nucleus supraopticus UDP.. phosphohydrolase (UDPase), GDP-phosphohydrolas...

The ability of muscarinic cholinergic agonists to interact with muscarinic receptors in nerve ending preparations and elicit an increased labeling of phosphatidate and phosphatidylinositol from 32Pi has been investigated. Two groups of brain muscarinic agonists are distinguished. Addition of acetylcholine, carbamylcholine, methacholine, or muscarine resulted in a 2-fold stimulation of phosphati...

Glucose 6-phosphatase from rat liver and kidney microsomes previously has been shown to catalyze an inorganic pyrophosphate-glucose phosphotransferase reaction. Nordlie and Soodsma recently have suggested that formation and then degradation of glucose 6-phosphate by the combined action of phosphotransferase and phosphohydrolase activities of this enzyme may under certain conditions constitute p...

background: phosphatidate phosphohydrolase (pap) catalyzes the dephosphorylation of phosphatidic acid to yield p i and diacylglycerol. two different forms of pap have been reported in rat hepatocyte: pap 1 that participates in the synthesis of phospholipids and triacylglycerols and pap 2 which is involved in lipid signaling pathways. two isoforms of pap 2 are pap 2a and pap 2b . this study exam...

Evidence for the involvement of Ca(2+) and calmodulin in the regulation of phospholipid breakdown by microsomal membranes from bean cotyledons has been obtained by following the formation of radiolabeled degradation products from [U-(14)C]phosphatidylcholine. Three membrane-associated enzymes were found to mediate the breakdown of [U-(14)C] phosphatidylcholine, viz. phospholipase D (EC 3.1.4.4)...

The effect of the sulfur-substituted fatty acid analogue 1,10 bis(carboxymethylthio)decane, also known as 3-thiadicarboxylic acid, on puromycin aminonucleoside-induced nephrotic hyperlipidemia was studied in rats. Treatment with 3-thiadicarboxylic acid (250 mg/kg) for 5 days reduced plasma levels of triglycerides from 5.8 to 2.7 mmol/L and cholesterol from 11.0 to 7.7 mmol/L. This was accounted...

Glucose 6-phosphatase from rat liver and kidney microsomes previously has been shown to catalyze an inorganic pyrophosphate-glucose phosphotransferase reaction. Nordlie and Soodsma recently have suggested that formation and then degradation of glucose 6-phosphate by the combined action of phosphotransferase and phosphohydrolase activities of this enzyme may under certain conditions constitute p...

Interest in our laboratory in the inositol lipids derives from the presence of relatively high amounts of phosphatidylinositol phosphate (PhIP) and phosphatidylinositol diphosphate (PhIPP) in excitable tissue. It was with this relationship in mind that we embarked on a study of biosynthetic pathways of inositol lipids several years ago. A first step in the elucidation of biosynthetic pathways o...

We found that glucagon stimulated membrane protein kinase C (PKC) activity and phosphatidylcholine hydrolysis in 24 h-cultured rat hepatocytes. Phorbol myristate acetate, 8-bromo cyclic AMP, vasopressin, noradrenaline and the Ca2+ ionophore A23187 also stimulated membrane PKC activity. However, only vasopressin and noradrenaline stimulated inositol phosphate accumulation, whereas all agonists s...