Inhibition lipid synthesis

Cerulenln most likely Interferes with morphogenesis by Inhibiting lipid synthesis. The mechanism whereby butyrate blocks morphogenesis Is unknown however the data suggest that Inhibition Is not directly related to reduced lipid synthesis. 

Adetumbi M, Javor GT, Lau BHS (1986) Allium sativum (garlic) inhibits lipid synthesis by... 

Pyrenocine A has bimodal effects on onion root and spinach chloroplast lipid metabolism. Low concentrations and shorter preincubation periods promote lipid synthesis from 14C-acetate while high concentrations and longer preincubation periods inhibit lipid synthesis. Maximum stimulation of lipid synthesis (approximately 75%) was observed when onion roots were preincubated for. 5 h with 25 Aig/ml pyrenocine A while maximum inhibition (approximately 80%) was observed when onion roots were pretreated with 100 ug/ml pyrenocine A for 24 h (Tables 1 and II). Over the range of onion treatments with pyrenocine A, there was a marked increase in the proportions of glycerolipid synthesized at the expense of sterols (50%... 

Increased lipid synthesis/inhibi-tion of lipolysis Activation of lipoprotein lipase (LPL)/induc-tion of fatty acid synthase (FAS)/inactivation of hormone sensitive lipase (HSL) Facilitated uptake of fatty acids by LPL-dependent hydrolysis of triacylglycerol from circulating lipoproteins. Increased lipid synthesis through Akt-mediated FAS-expression. Inhibition of lipolysis by preventing cAMP-dependent activation of HSL (insulin-dependent activation of phosphodiesterases )... 

Mouse peritoneal macrophages that have been activated to produce nitric oxide by 7-interferon and lipopolysac-charide were shown to oxidize LDL less readily than unactivated macrophages. Inhibition of nitric oxide synthesis in the same model was shown to enhance LDL oxidation (Jessup etal., 1992 Yates a al., 1992). It has recently been demonstrated that nitric oxide is able to inhibit lipid peroxidation directly within LDL (Ho etal., 1993c). Nitric oxide probably reacts with the propagating peroxyl radicals thus terminating the chain of lipid peroxidation. The rate constant for the reaction between nitric oxide and peroxyl radicals has recently been determined to be 1-3 X10 M" s (Padmaja and Huie, 1993). This... 

The health impairing and toxic elfects of oxidation of lipids are due to loss of vitamins, polyenoic fatty acids, and other nutritionally essential components formation of radicals, hydroperoxides, aldehydes, epoxides, dimers, and polymers and participation of the secondary products in initiation of oxidation of proteins and in the Maillard reaction. Dilferent oxysterols have been shown in vitro and in vivo to have atherogenic, mutagenic, carcinogenic, angiotoxic, and cytotoxic properties, as well as the ability to inhibit cholesterol synthesis (Tai et ah, 1999 Wpsowicz, 2002). 

Rifampin is a semisynthetic macrocyclic antibiotic produced from Streptomyces mediterranei. It is a large lipid-soluble molecule that is bactericidal for both intracellular and extracellular microorganisms. Rifampin binds strongly to the p-subunit of bacterial DNA-dependent RNA polymerase and thereby inhibits RNA synthesis. Rifampin does not affect mammalian polymerases. 

The dicarboximides inhibit spore germination and cause increased branching, swelling and lysis of germ tubes and hyphal tips. Effects on cell division have been reported but no major inhibition of nucleic acid metabolism, respiration, protein or lipid synthesis has been observed. 

Depletion of ATP is caused by many toxic compounds, and this will result in a variety of biochemical changes. Although there are many ways for toxic compounds to cause a depletion of ATP in the cell, interference with mitochondrial oxidative phosphorylation is perhaps the most common. Thus, compounds, such as 2,4-dinitrophenol, which uncouple the production of ATP from the electron transport chain, will cause such an effect, but will also cause inhibition of electron transport or depletion of NADH. Excessive use of ATP or sequestration are other mechanisms, the latter being more fully described in relation to ethionine toxicity in chapter 7. Also, DNA damage, which causes the activation of poly(ADP-ribose) polymerase (PARP), may lead to ATP depletion (see below). A lack of ATP in the cell means that active transport into, out of, and within the cell is compromised or halted, with the result that the concentration of ions such as Na+, K+, and Ca2+ in particular compartments will change. Also, various synthetic biochemical processes such as protein synthesis, gluconeogenesis, and lipid synthesis will tend to be decreased. At the tissue level, this may mean that hepatocytes do not produce bile efficiently and proximal tubules do not actively reabsorb essential amino acids and glucose. 

Increased synthesis of lipid or uptake. Increased synthesis of lipid may be the cause of fatty liver after hydrazine administration as this compound increases the activity of the enzyme involved in the synthesis of diglycerides. Hydrazine also depletes ATP and, however, inhibits protein synthesis. Large doses of ethanol will cause fatty liver in humans, and it is believed that this is partly due to an increase in fatty acid synthesis. This is a result of an increase in the NADH/NAD"1" ratio and therefore of the synthesis of triglycerides. Changes in the mobilization of lipids in tissues followed by uptake into the liver can also be another cause of steatosis. 

Figs. 12—16 to 12—22) and prevent the progressive course of Alzheimer s disease. Direct inhibition of gene expression for the biosynthesis of these proteins is not currently possible and is currently not a very feasible therapeutic possibility. Perhaps a more realistic therapeutic possibility would be to inhibit the synthesis of beta amyloid, in much the same way that lipid-lowering agents act to inhibit the biosynthesis of cholesterol in order to prevent atherosclerosis. This could be done by means of enzyme inhibitors, such as protease inhibitors, which are at least a theoretical possibility. 

Resveratrol has also been reported to offer protection against cardiovascular disease, such as coronary heart disease. The effects of resveratrol on factors implicated in the development of coronary heart disease - human platelet aggregation and the synthesis of eicosanoids (lipids) from arachidonate by platelets - were investigated and compared with the actions of other wine phenolics - catechin (1.39), epicatechin (7.18a), and quercetin (1.43) - and the antioxidants a-tocopherol (7.10a), hydroquinone and butylated hydroxytoluene. Resveratrol and quercetin demonstrated a dose-dependent inhibition of platelet aggregation, whereas the other compounds tested were inactive. Resveratrol also inhibited the synthesis of the eicosanoids in a dose-dependent manner, whereas the other phenolics were less effective of not effective at all. Removal of the alcohol from the wine did not diminish the effect on platelet aggregation (Pace-Asciak et al., 1995 Goldberg et al., 1995). 

Radin, N. S., Shayman,J. A.,and Inokuchi,J. (1993). Metabolic effects of inhibiting glucosylceramide synthesis with PDMP and other substances. Adv. Lipid Res. 26, 183-213. 

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