Rates of phosphatidate synthesis from dihydroxyacetone phosphate via acyl dihydroxyacetone phosphate or glycerol phosphate are compared in homogenates of 13 tissues, most of which are deficient in glycerol phosphate dehydrogenase (EC 1.1.1.8). In all tissues examined, dihydroxyacetone phosphate entered phosphatidate more rapidly via acyl dihydroxyacetone phosphate than via glycerol phosphate. T...

Acetylcholine increases the incorporation of 32P1 into phosphatidate of guinea-pig brain synaptosomes incubated in vitro (Durell & Sodd, 1966; Schacht & Agranoff, 1972; Yagihara & Hawthorne, 1972). Three pathways for the synthesis of phosphatidate operate in brain tissue: acylation of glycerol 3-phosphate, acylation of dihydroxyacetone phosphate (Pollock et al., 1975) and the phosphorylation of...

The two purified nucleoside triphosphate phosphohydrolases from vaccinia virus are distinct enzymes as judged by their nucleotide substrate and polynucleotide cofactor specificities. Phosphohydrolase I hydrolyzes only ATP and dATP, whereas phosphohydrolase II hydrolyzes the four common ribonucleoside triphosphates as well as dATP and TTP. The range of K, values for ATP and dATP hydrolysis by ph...

Although adenine-requiring auxotrophs of Bacillus subtilis accumulate large quantities of inosine or hypoxanthine, or of both, they do not accumulate inosine-5'-monophosphate (IMP). Experiments directed at understanding this phenomenon were conducted with an adenineless auxotroph and with a mutant derived from it which lacked alkaline phosphohydrolase. It was found that B. subtilis contains fou...

Bradykinin (BK) induced a biphasic increase in 1,2-diacylglycerol (DAG) in both K-ras-transformed fibroblasts (DT) and the parent NIH-3T3 cells. The first phase was coincident with the increase in Ins(1,4,5)P3 resulting from PtdIns(4,5)P2 hydrolysis, and the second, sustained, phase was derived from phosphatidylcholine (PtdCho) hydrolysis. In NIH-3T3 cells, stimulation by BK induced greater pro...

Stimulation of secretion in guinea pig parotid gland lobules by either isoproterenol or carbachol is associated with a removal of acyl groups from the acyl-CoA pool and their incorporation into diacylglycerols and triglycerides (Söling, H. D., Machado-De Domenech, E., Kleineke, J., and Fest, W. (1987) J. Biol. Chem. 262, 16786-16792). This is associated with an increased incorporation of glycer...

1. A comparative study was made of triglyceride synthesis by the intestinal epithelium of pigs, sheep and chickens. In pig and chicken tissue both the glycerol 3-phosphate and the monoglyceride pathway of triglyceride synthesis were operative, but the former pathway predominated in sheep tissue. 2. The fatty acid specificity of the glycerol 3-phosphate pathway was studied in pig and sheep total...

The effect of dietary octacosanol, a long-chain alcohol, on lipid metabolism was investigated in rats fed on a high-fat diet for 20 d. The addition of octacosanol (10 g/kg diet) to the high-fat diet led to a significant reduction (P < 0.05) in the perirenal adipose tissue weight without decrease of the cell number, suggesting that octacosanol may suppress lipid accumulation in this tissue, wher...

Lipin-1 is a phosphatidate phosphohydrolase (PAP) required for the generation of diacylglycerol during glycerolipid synthesis, and exhibits dual functions in the regulation of lipid metabolism. Lipin-1 has been implicated in the pathogenesis of alcoholic liver disease (ALD). In the present study, we assessed lipin-1 function in myeloid cells in ALD using a myeloid cell-specific lipin-1 knockout...

A variety of amphiphilic cations caused very large increases in the rates of incorporation of Pi and glycerol into phosphatidylinositol in pig mesenteric small lymphocytes. This synthesis de novo of phosphatidylinositol led to a doubling of the phosphatidylinositol concentration in the cells within 3.5 h. The increase in synthesis of phosphatidylinositol labelled with [3H]- or [14C]-glycerol wa...