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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both starvation of and feeding a high linoleic acid content diet to rats during late pregnancy resulted in marked differences in the metabolism of the fed offspring immediately after birth when compared to control neonates (mother fed the normal high carbohydrate content laboratory diet during pregnancy). In particular differences in postnatal changes in blood glucose, non esterified fatty acids and ketone bodies and in hepatic triglyceride content were observed. Many of the differences appeared to be related to the variations in blood and hepatic metabolites present at birth in the various groups of animals. A similar situation also existed with respect to postnatal changes in the activity of hydroxymethylglutaryl-CoA synthase.
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PMID:The effect of maternal diet during late pregnancy on postnatal changes in blood and liver metabolites and hepatic hydroxymethylglutaryl-CoA synthase activity in the offspring. 285 9

1. The activities of hydroxymethylglutaryl-CoA synthase and lyase in rat liver were found to be two- to 15-fold greater than those reported by other authors under similar conditions. 2. When expressed on the basis of body weight, no appreciable differences were found between the activities of hydroxymethylglutaryl-CoA synthase in whole homogenates of livers from normal and starved rats. The synthase activity increased by 70% and 140% in livers of alloxan-diabetic rats and rats fed on a high-fat diet respectively. 3. Hydroxymethylglutaryl-CoA lyase activity showed no significant increases in starvation or alloxan-diabetes, but a 40% increase was found in fat-fed rats. 4. Less than 12% of the activities of both enzymes were found in the cytoplasmic fraction of normal liver. The cytoplasmic activity doubled in alloxan-diabetes and starvation; on feeding with a high-fat diet the increase, though significant, was less marked. 6. The intracellular distribution of glutamate dehydrogenase indicated that the changes in the cytoplasmic activities observed were not due to leakage from the mitochondria. 7. Feeding with a normal or high-fat diet after 48hr. starvation caused within 24hr. a decrease in the cytoplasmic activity of hydroxymethylglutaryl-CoA synthase to values lower than those found in rats fed on a corresponding diet for a longer period of time. 8. Acetoacetyl-CoA deacylase activity in liver was about 20% of that of hydroxymethylglutaryl-CoA synthase and was primarily located in the cytoplasm. Starvation or alloxan-diabetes did not alter the acetoacetyl-CoA deacylase activity. 9. It is concluded that variations in the concentrations of enzymes involved in acetoacetate synthesis play no major role in the regulation of ketone-body formation in starvation and alloxan-diabetes. The changes in the cytoplasmic activities of hydroxymethylglutaryl-CoA synthase and lyase suggest that acetoacetate synthesis can occur in the cytoplasm. This may play a role in the disposal of surplus acetyl-CoA arising in the cytoplasm when lipogenesis is inhibited.
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PMID:Activity and intracellular distribution of enzymes of ketone-body metabolism in rat liver. 566 51

Glucose and fatty acid metabolism (oxidation versus esterification) has been measured in hepatocytes isolated from 24 h starved peroxisome proliferator-activated receptor-alpha (PPARalpha) null and wild-type mice. In PPARalpha null mice, the development of hypoglycemia during starvation was due to a reduced capacity for hepatic gluconeogenesis secondary to a 70% lower rate of fatty acid oxidation. This was not due to inappropriate expression of the hepatic CPT I gene, which was similar in both genotypes, but to impaired mitochondrial hydroxymethylglutaryl-CoA synthase gene expression in the PPARalpha null mouse liver. We also demonstrate that hepatic steatosis of fasting PPARalpha null mice was not due to enhanced triglyceride synthesis.
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PMID:Reduced hepatic fatty acid oxidation in fasting PPARalpha null mice is due to impaired mitochondrial hydroxymethylglutaryl-CoA synthase gene expression. 1086 48

In the process of membrane biogenesis several dozen proteins must operate in precise concert to generate approximately 100 lipids at appropriate concentrations. To study the regulation of bilayer assembly in a cell cycle-independent manner, we have exploited the fact that phagocytes replenish membranes expended during particle engulfment in a rapid phase of lipid synthesis. In response to phagocytosis of latex beads, human embryonic kidney 293 cells synthesized cholesterol and phospholipids at amounts equivalent to the surface area of the internalized particles. Lipid synthesis was accompanied by increased transcription of several lipogenic proteins, including the low-density lipoprotein receptor, enzymes required for cholesterol synthesis (3-hydroxy-3-methylglutaryl CoA synthase, 3-hydroxy-3-methylglutaryl CoA reductase), and fatty acid synthase. Phagocytosis triggered the proteolytic activation of two lipogenic transcription factors, sterol regulatory element binding protein-1a (SREBP-1a) and SREBP-2. Proteolysis of SREBPs coincided with the appearance of their transcriptionally active N termini in the nucleus and 3-fold activation of an SREBP-specific reporter gene. In previous studies with cultured cells, proteolytic activation of SREBP-1a and SREBP-2 has been observed in response to selective starvation of cells for cholesterol and unsaturated fatty acids. However, under the current conditions, SREBP-1a and SREBP-2 are induced without lipid deprivation. SREBP activation is inhibited by high levels of the SREBP-interacting proteins Insig1 or the cytosolic domain of SREBP cleavage-activating protein. Upon overexpression of these proteins, phagocytosis-induced transcription and lipid synthesis were blocked. These results identify SREBPs as essential regulators of membrane biogenesis and provide a useful system for further studies on membrane homeostasis.
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PMID:Transcriptional regulation of phagocytosis-induced membrane biogenesis by sterol regulatory element binding proteins. 1614 15