Development of lipogenesis and insulin sensitivity in tissues of the ob/ob mouse

1981 ◽  
Vol 240 (2) ◽  
pp. E101-E107 ◽  
Author(s):  
M. L. Kaplan ◽  
G. A. Leveille
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Insulin Sensitivity ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Glycogen Synthesis ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Glycerophosphate Dehydrogenase

Lipogenesis and insulin sensitivity are evaluated in adipose tissue, liver, and diaphragm of ob/ob and non-ob/ob mice. In ob/ob mice, hepatic fatty acid synthesis from [U-14C]glucose is elevated by 4 wk of age, and adipose tissue fatty acid synthesis increases at approximately 7 wk. Hepatic activities in ob/ob mice of glucose-6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), malate dehydrogenase (EC 1.1.1.40), and alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) are dramatically increased by 7 wk of age. Diminished insulin-stimulated glycogen synthesis is first noted in the diaphragm of ob/ob mice at 7 wk of age. Insulin-stimulated glycogen synthesis in adipose tissue of ob/ob mice is impaired at 3 wk. At 7 wk, insulin-stimulated fatty acid synthesis in adipose tissue of ob/ob mice is markedly increased. Adipose tissue glyceride-glycerol synthesis continues to increase throughout development, whereas fatty acid synthesis decreases after 7 wk. The data suggest that alterations in lipid synthesis occur very early in the development of ob/ob mouse, prior to expression to overt obesity, at which time a major contribution to lipogenesis is made by the liver. The altered de novo lipogenesis does not precede the reported diminution in energy metabolism.

Effects of pregnancy and ovarian steroids on fatty acid synthesis and uptake in Syrian hamsters

1991 ◽  
Vol 260 (1) ◽  
pp. R153-R158 ◽  
Author(s):  
A. J. Bhatia ◽  
G. N. Wade
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Ovarian Steroids ◽  
Syrian Hamsters

The effects of pregnancy and ovarian steroids on the in vivo distribution of newly synthesized fatty acids (incorporation of tritium from 3H2O into fatty acid) in Syrian hamsters (Mesocricetus auratus) were examined. During late, but not early, gestation hamsters had reduced levels of newly synthesized fatty acids in heart, liver, uterus, and white adipose tissues (parametrial and inguinal fat pads). Treatment of ovariectomized hamsters with estradiol + progesterone significantly decreased fatty acid synthesis-uptake in heart, liver, and inguinal white adipose tissue. Treatment with either estradiol or progesterone alone was without significant effect in any tissue. Pretreatment of hamsters with Triton WR-1339 (tyloxapol), an inhibitor of lipoprotein lipase activity and tissue triglyceride uptake, abolished the effects of estradiol + progesterone in white adipose tissue and heart but not in liver. Thus hamsters lose body fat during pregnancy in part because of decreased de novo lipogenesis. The effect of pregnancy on lipogenesis is mimicked by treatment with estradiol + progesterone but not by either hormone alone. Furthermore, it appears that the liver is the principal site of estradiol + progesterone action on lipogenesis in Syrian hamsters.

scholarly journals Sterol regulatory element binding protein and dietary lipid regulation of fatty acid synthesis in the mammary epithelium

2010 ◽  
Vol 299 (6) ◽  
pp. E918-E927 ◽  
Author(s):  
Michael C. Rudolph ◽  
Jenifer Monks ◽  
Valerie Burns ◽  
Meridee Phistry ◽  
Russell Marians ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Regulatory Element ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Mrna Levels ◽  
Sterol Regulatory Element

The lactating mammary gland synthesizes large amounts of triglyceride from fatty acids derived from the blood and from de novo lipogenesis. The latter is significantly increased at parturition and decreased when additional dietary fatty acids become available. To begin to understand the molecular regulation of de novo lipogenesis, we tested the hypothesis that the transcription factor sterol regulatory element binding factor (SREBF)-1c is a primary regulator of this system. Expression of Srebf1c mRNA and six of its known target genes increased ≥2.5-fold at parturition. However, Srebf1c-null mice showed only minor deficiencies in lipid synthesis during lactation, possibly due to compensation by Srebf1a expression. To abrogate the function of both isoforms of Srebf1, we bred mice to obtain a mammary epithelial cell-specific deletion of SREBF cleavage-activating protein (SCAP), the SREBF escort protein. These dams showed a significant lactation deficiency, and expression of mRNA for fatty acid synthase ( Fasn), insulin-induced gene 1 ( Insig1), mitochondrial citrate transporter ( Slc25a1), and stearoyl-CoA desaturase 2 ( Scd2) was reduced threefold or more; however, the mRNA levels of acetyl-CoA carboxylase-1α ( Acaca) and ATP citrate lyase ( Acly) were unchanged. Furthermore, a 46% fat diet significantly decreased de novo fatty acid synthesis and reduced the protein levels of ACACA, ACLY, and FASN significantly, with no change in their mRNA levels. These data lead us to conclude that two modes of regulation exist to control fatty acid synthesis in the mammary gland of the lactating mouse: the well-known SREBF1 system and a novel mechanism that acts at the posttranscriptional level in the presence of SCAP deletion and high-fat feeding to alter enzyme protein.

Translational control by mTOR-independent routes: how eIF6 organizes metabolism

2016 ◽  
Vol 44 (6) ◽  
pp. 1667-1673 ◽  
Author(s):  
Annarita Miluzio ◽  
Sara Ricciardi ◽  
Nicola Manfrini ◽  
Roberta Alfieri ◽  
Stefania Oliveto ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Insulin Sensitivity ◽  
Fatty Acid Synthesis ◽  
Translational Control ◽  
Metabolic Diseases ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Translational Machinery

Over the past few years, there has been a growing interest in the interconnection between translation and metabolism. Important oncogenic pathways, like those elicited by c-Myc transcription factor and mTOR kinase, couple the activation of the translational machinery with glycolysis and fatty acid synthesis. Eukaryotic initiation factor 6 (eIF6) is a factor necessary for 60S ribosome maturation. eIF6 acts also as a cytoplasmic translation initiation factor, downstream of growth factor stimulation. eIF6 is up-regulated in several tumor types. Data on mice models have demonstrated that eIF6 cytoplasmic activity is rate-limiting for Myc-induced lymphomagenesis. In spite of this, eIF6 is neither transcriptionally regulated by Myc, nor post-transcriptionally regulated by mTOR. eIF6 stimulates a glycolytic and fatty acid synthesis program necessary for tumor growth. eIF6 increases the translation of transcription factors necessary for lipogenesis, such as CEBP/β, ATF4 and CEBP/δ. Insulin stimulation leads to an increase in translation and fat synthesis blunted by eIF6 deficiency. Paradoxycally, long-term inhibition of eIF6 activity increases insulin sensitivity, suggesting that the translational activation observed upon insulin and growth factors stimulation acts as a feed-forward mechanism regulating lipid synthesis. The data on the role that eIF6 plays in cancer and in insulin sensitivity make it a tempting pharmacological target for cancers and metabolic diseases. We speculate that eIF6 inhibition will be particularly effective especially when mTOR sensitivity to rapamycin is abrogated by RAS mutations.

Captopril enhanced insulin-stimulated glycogen synthesis in skeletal muscle but not fatty acid synthesis in adipose tissue of hereditary hypertriglyceridemic rats

Metabolism ◽  
2003 ◽  
Vol 52 (11) ◽  
pp. 1406-1412 ◽  
Author(s):  
Monika Cahová ◽  
Hana Vavrinková ◽  
Milada Tutterova ◽  
Elen Meschisvilli ◽  
Ludmila Kazdova
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Glycogen Synthesis ◽  
Acid Synthesis

scholarly journals Downregulation of de Novo Fatty Acid Synthesis in Subcutaneous Adipose Tissue of Moderately Obese Women

2015 ◽  
Vol 16 (12) ◽  
pp. 29911-29922 ◽  
Author(s):  
Esther Guiu-Jurado ◽  
Teresa Auguet ◽  
Alba Berlanga ◽  
Gemma Aragonès ◽  
Carmen Aguilar ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Subcutaneous Adipose Tissue ◽  
De Novo ◽  
Acid Synthesis ◽  
Obese Women ◽  
Subcutaneous Adipose

scholarly journals Analysis of lines of mice selected for fat content: 3. Flux through the de novo lipid synthesis pathway

1991 ◽  
Vol 58 (2) ◽  
pp. 123-127 ◽  
Author(s):  
Emmanuel A. Asante ◽  
William G. Hill ◽  
Grahame Bulfield
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Lipid Synthesis ◽  
Fold Increase ◽  
Acid Synthesis ◽  
Fat Content ◽  
Direct Selection ◽  
Lean Line

SummaryThe flux through the de novo fatty acid synthesis pathway was estimated in lines of mice which differed substantially in fat content following 26 generations of selection at 10 weeks of age. Previous estimates of lipogenic enzyme activities had indicated an increase in the capacity for lipogenesis in the Fat compared to the Lean line. Therefore the in vivo flux in lipogenesis was measured in both liver and gonadal fat pad (GFP) tissues of males at 5 and 10 weeks of age, using the rat of incorporation of 3H from 3H2O and 14C from acetate and citra te into total lipids. AT both ages and in both tissues the Fat line had a higher flux, about 20% increase in the liver and up to three-fold increase (range 1·2- to 3·4-fold) in the GFP. We conclude that direct selection for fatness in mice has resulted in metabolic changes in the ratio of de novo fatty acid synthesis, and that the changes are largely detectable before 10 weeks, the age of selection.

scholarly journals The Role of Mitochondrial Fat Oxidation in Cancer Cell Proliferation and Survival

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2600
Author(s):  
Matheus Pinto De Oliveira ◽  
Marc Liesa
Keyword(s):  
Oxidative Stress ◽  
Colorectal Cancer ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Cancer Proliferation

Tumors remodel their metabolism to support anabolic processes needed for replication, as well as to survive nutrient scarcity and oxidative stress imposed by their changing environment. In most healthy tissues, the shift from anabolism to catabolism results in decreased glycolysis and elevated fatty acid oxidation (FAO). This change in the nutrient selected for oxidation is regulated by the glucose-fatty acid cycle, also known as the Randle cycle. Briefly, this cycle consists of a decrease in glycolysis caused by increased mitochondrial FAO in muscle as a result of elevated extracellular fatty acid availability. Closing the cycle, increased glycolysis in response to elevated extracellular glucose availability causes a decrease in mitochondrial FAO. This competition between glycolysis and FAO and its relationship with anabolism and catabolism is conserved in some cancers. Accordingly, decreasing glycolysis to lactate, even by diverting pyruvate to mitochondria, can stop proliferation. Moreover, colorectal cancer cells can effectively shift to FAO to survive both glucose restriction and increases in oxidative stress at the expense of decreasing anabolism. However, a subset of B-cell lymphomas and other cancers require a concurrent increase in mitochondrial FAO and glycolysis to support anabolism and proliferation, thus escaping the competing nature of the Randle cycle. How mitochondria are remodeled in these FAO-dependent lymphomas to preferably oxidize fat, while concurrently sustaining high glycolysis and increasing de novo fatty acid synthesis is unclear. Here, we review studies focusing on the role of mitochondrial FAO and mitochondrial-driven lipid synthesis in cancer proliferation and survival, specifically in colorectal cancer and lymphomas. We conclude that a specific metabolic liability of these FAO-dependent cancers could be a unique remodeling of mitochondrial function that licenses elevated FAO concurrent to high glycolysis and fatty acid synthesis. In addition, blocking this mitochondrial remodeling could selectively stop growth of tumors that shifted to mitochondrial FAO to survive oxidative stress and nutrient scarcity.

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