Triglycerides accumulation

Burgermeister, E., Schnoebelen, A., Flament, A., Benz, J., Stihle, M., Gsell, B., Rufer, A., Ruf, A., Kuhn, B., Marki, H. P., Mizrahi, J., Sebokova, E., et al. (2006). A novel agonist of peroxiome proliferator-activated receptor-y (PPAR y) recruits PPAR y-coactivator-la, prevents triglyceride accumulation, and potentiates insuling signalling in vitro. Mol. Endocrinol. 20, 809-830. 

Answer D. Triglyceride accumulation in muscle is not normal and indicates fatty acids are not entering the mitochondria normally. 

The relative importance of hepatic microsomal lipid peroxidation versus covalent binding of carbon tetrachloride-derived radicals has been the subject of considerable debate. Since cytochrome P-450 loss has been shown to be related to lipid peroxidation and to covalent binding, each in the absence of the other, both of these early consequences of carbon tetrachloride metabolism may contribute to P-450 destruction. Nevertheless, it is still not clear how these initial events are related to subsequent triglyceride accumulation, polyribosomal disaggregation, depression of protein synthesis, cell membrane breakdown and eventual death of the hepatocytes. Carbon tetrachloride... 

The accumulation of fat is a common cellular response to toxic compounds, which is normally reversible. Usually triglycerides accumulate, although sometimes phospholipids accumulate, as occurs after exposure to the drug chlorphentermine (see chap. 2). Steatosis is particularly common in the liver as this organ has a major role in lipid metabolism (Fig. 6.15). The lipid may appear in the cell as many small droplets or as one large droplet. Interference with lipid metabolism can occur at several points ... 

After a single dose of ethionine, triglycerides accumulate in the liver, the increase being detectable after four hours. After 24 hours, the accumulation of triglycerides is maximal, being 15 to 20 times the normal level. Initially, the fat droplets accumulate on the endoplasmic reticulum in periportal hepatocytes and then in more central areas of the liver. Some species develop hepatic necrosis as well as fatty liver, and nuclear changes and disruption of the endoplasmic reticulum may also be observed. 

Timbrell et al. (1996) reported that much higher hydrazine concentrations were required in rat hepatocyte cultures in comparison to plasma concentrations in male Sprague-Dawley rats to elicit the following hepatic/hepatocellular effects lactate dehydrogenase leakage, ATP and GST depletion, increase in citrulline level, protein synthesis inhibition, taurine leakage and triglyceride accumulation. 

Three studies examined the mediating effect of phenobarbital on white phosphorus-induced liver function impairment. Pre-treatment with four or five intraperitoneal injections of phenobarbital showed no effect on white phosphorus-induced triglyceride accumulation at 12 hours after white phosphorus administration (Pani et al. 1972), but had an antagonistic effect on white phosphorus-induced increases in BSP retention at 24 hours after treatment with white phosphorus (Hurwitz 1972). The antagonistic effect of phenobarbital pretreatment on white phosphorus-induced BSP retention disappeared by 48 hours after white phosphorus administration. Another study conducted by Hurwitz (1972) showed the antagonistic effect of 4 daily intraperitoneal post-treatments with phenobarbital on white phosphorus-induced mortality. 

GH, together with other hormones, can induce differentiation of cells of the 3T3 mouse fibroblast line into adipocytes in vitro [98,99]. The change involves morphological alterations, enzymic differentiation, increased hormone responsiveness, triglyceride accumulation and a limited mitogenic response. Somatomedin C has no effect on this transformation. 

Collins KA, Korcarz CE, Lang RM (2003) Use of echocardiography for the phenotypic assessment of genetically altered mice. Physiological Genomics 13 227-239 Daubioul C, Rousseau N, Demeure R et al. (2002) Dietary fruc-tans, but not cellulose, decrease triglyceride accumulation in the liver of obese Zucker fa/fa rats. Journal of Nutrition 132 967-973... 

Intrahepatic events contributing to increased fatty acid availability include enhanced de novo synthesis and impaired p-oxidation, whereas increased esterification would lead to triglyceride accumulation. Each of these processes is sensitive to... 

Borradaile, N. M., de Dreu, L. E., Barrett, P. H., Behrsin, C. D., Huff, M. W. (2003). Hepato-cyte apoB-containing lipoprotein secretion is decreased by the grapefruit flavonoid, naringenin, via inhibition of MTP-mediated microsomal triglyceride accumulation. Biochemistry, 42, 1283-1291. 

A cardiologist is studying the effect of alcohol on triglyceride accumulation in rat heart. The triglycerides are saponified and the glycerol released is determined by the coupled enzyme system shown below. 

M. Cnop, J.C. Hannaert, A. Hoorens, D.L. Eizirik, and D.G. Pipeleers, Inverse relationship between cytotoxicity of free fatty acids in pancreatic islet cells and cellular triglyceride accumulation. Diabetes, 2001, 50, 1771-1777. 

S. Cases, R.V. Farese, D.S. Ory, and J.E. Schaffer, Triglyceride accumulation protects against fatty acid-induced lipotoxicity, Proc. Natl. Acad. Sci. USA, 2003, 700, 3077-3082. 

After a single dose of ethionine, triglycerides accumulate in the liver, the increase being detectable after four hours. After 24 hours the accumulation of triglycerides is maximal, being 15-20 times the normal... 

Mao, J., DeMayo, F. J., Li, H., Abu-Elheiga, L., Gu, Z., Shaikenov, T. E., Kordari, P., Chirala, S. S., Heird, W. C., and Wakil, S. J. Liver-specific deletion of acetyl-CoA carboxylase 1 reduces hepatic triglyceride accumulation without affecting glucose homeostasis. Proc Natl Acad Sci U S A 103 (2006) 8552-8557. 

Effect of Other Fatty Acids on the Triglyceride Accumulation in the Rat Heart as a Result of Feeding Erucic Acid Containing Diets... 

Cnop, M Hannaert, JC Hoorens, A Eizirik, DL Pipeleers, DG. Inverse Relationship Between Cytotoxicity of Free Fatty Acids in Pancreatic Islet Cells and Cellular Triglyceride Accumulation. Diabetes, 2001 50(8) 1771-7. 

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