Reassessing triglyceride synthesis in adipose tissue

2008 ◽  
Vol 19 (10) ◽  
pp. 356-361 ◽  
Author(s):  
Colleen Nye ◽  
Jaeyeon Kim ◽  
Satish C. Kalhan ◽  
Richard W. Hanson
1987 ◽  
Vol 253 (6) ◽  
pp. E664-E669 ◽  
Author(s):  
C. Chascione ◽  
D. H. Elwyn ◽  
M. Davila ◽  
K. M. Gil ◽  
J. Askanazi ◽  
...  

Rates of synthesis, from [14C]glucose, of fatty acids (de novo lipogenesis) and glycerol (triglyceride synthesis) were measured in biopsies of adipose tissue from nutritionally depleted patients given low- or high-carbohydrate intravenous nutrition. Simultaneously, energy expenditure and whole-body lipogenesis were measured by indirect calorimetry. Rates of whole-body lipogenesis were zero on the low-carbohydrate diet and averaged 1.6 g.kg-1.day-1 on the high-carbohydrate diet. In vitro rates of triglyceride synthesis increased 3-fold going from the low to the high intake; rates of fatty acid synthesis increased approximately 80-fold. In vitro, lipogenesis accounted for less than 0.1% of triglyceride synthesis on the low intake and 4% on the high intake. On the high-carbohydrate intake, in vitro rates of triglyceride synthesis accounted for 61% of the rates of unidirectional triglyceride synthesis measured by indirect calorimetry. In vitro rates of lipogenesis accounted for 7% of whole-body lipogenesis. Discrepancies between in vitro rates of fatty acid synthesis from glucose, compared with acetate and citrate, as reported by others, suggest that in depleted patients on hypercaloric high-carbohydrate diets, adipose tissue may account for up to 40% of whole-body lipogenesis.


2008 ◽  
Vol 284 (10) ◽  
pp. 6101-6108 ◽  
Author(s):  
Ilya R. Bederman ◽  
Steven Foy ◽  
Visvanathan Chandramouli ◽  
James C. Alexander ◽  
Stephen F. Previs

1974 ◽  
Vol 76 (2) ◽  
pp. 359-364 ◽  
Author(s):  
Nobuo MATSUOKA ◽  
Yasushi SAITO ◽  
Hiromichi OKUDA ◽  
Setsuro FUJII

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Shoba Shetty ◽  
Maria A. Ramos-Roman ◽  
You-Ree Cho ◽  
Jonathan Brown ◽  
Jorge Plutzky ◽  
...  

Adiponectin overexpression in mice increases insulin sensitivity independent of adiposity. Here, we combined stable isotope infusion and in vivo measurements of lipid flux with transcriptomic analysis to characterize fatty acid metabolism in transgenic mice that overexpress adiponectin via the aP2-promoter (ADNTg). Compared with controls, fasted ADNTg mice demonstrated a 31% reduction in plasma free fatty acid concentrations (P = 0.008), a doubling of ketones (P = 0.028), and a 68% increase in free fatty acid turnover in plasma (15.1 ± 1.5 vs. 25.3 ± 6.8 mg/kg · min, P = 0.011). ADNTg mice had 2-fold more brown adipose tissue mass, and triglyceride synthesis and turnover were 5-fold greater in this organ (P = 0.046). Epididymal white adipose tissue was slightly reduced, possibly due to the approximately 1.5-fold increase in the expression of genes involved in oxidation (peroxisome proliferator-activated receptor α, peroxisome proliferator-activated receptor-γ coactivator 1α, and uncoupling protein 3). In ADNTg liver, lipogenic gene expression was reduced, but there was an unexpected increase in the expression of retinoid pathway genes (hepatic retinol binding protein 1 and retinoic acid receptor beta and adipose Cyp26A1) and liver retinyl ester content (64% higher, P < 0.02). Combined, these data support a physiological link between adiponectin signaling and increased efficiency of triglyceride synthesis and hydrolysis, a process that can be controlled by retinoids. Interactions between adiponectin and retinoids may underlie adiponectin's effects on intermediary metabolism.


Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1386
Author(s):  
Andrew J. Lutkewitte ◽  
Brian N. Finck

Phosphatidic acid (PA) is a glycerophospholipid intermediate in the triglyceride synthesis pathway that has incredibly important structural functions as a component of cell membranes and dynamic effects on intracellular and intercellular signaling pathways. Although there are many pathways to synthesize and degrade PA, a family of PA phosphohydrolases (lipin family proteins) that generate diacylglycerol constitute the primary pathway for PA incorporation into triglycerides. Previously, it was believed that the pool of PA used to synthesize triglyceride was distinct, compartmentalized, and did not widely intersect with signaling pathways. However, we now know that modulating the activity of lipin 1 has profound effects on signaling in a variety of cell types. Indeed, in most tissues except adipose tissue, lipin-mediated PA phosphohydrolase activity is far from limiting for normal rates of triglyceride synthesis, but rather impacts critical signaling cascades that control cellular homeostasis. In this review, we will discuss how lipin-mediated control of PA concentrations regulates metabolism and signaling in mammalian organisms.


2020 ◽  
Author(s):  
Weiguo Lao ◽  
Yi Tan ◽  
Michael Johnson ◽  
Yan Li ◽  
Yiguang Lin ◽  
...  

Abstract Background: Osteoporosis is a metabolic disease affecting the bone mineral density associated with increased adiposity in the aging population with obesity. The nutrients to control osteoblast and adipocyte differentiation from a common precursor, the pluripotent mesenchymal stem cell (MSC), may be a promising therapy for osteoporosis. Previously, we have shown that green tea polyphenols (GTP) exert anti-adipogenic effects on preadipocyte proliferation. In the present study, we investigated regulatory effects of GTP on osteogenesis and adipogenesis during early differentiation of human adipose tissue-derived stem cells (hADSCs). Methods: GTP at concentrations of 1 and 10 µg/ml was incubated with primary hADSCs in presence or absence of pioglitazone (100 µmol) during hADSCs differentiation. Adipogenesis of hADSCs was determined by Oil Red O staining and measurement of the cellular triglyceride synthesis in mature adipocyte. Alkaline phosphatase (ALP) assay and the measurement of intracellular calcium were utilized to determine osteoporosis of hADSCs. Immunofluorescence staining and qRT-PCR were employed to detect PPARγ-CEBPA regulated adipogenic pathway and the RUNX2-BMP2 mediated osteogenic pathway. Results: GTP treatment significantly decreased lipid accumulation and the cellular triglyceride synthesis in mature adipocytes and attenuated pioglitazone-induced adipogenesis in a dose-dependent manner. GTP downregulated protein and mRNA expression of Pparγ and attenuated pioglitazone-stimulated Cebpa expression in mature adipocytes. Concurrently, measurements of calcium content and ALP activity showed that GTP treatment significantly enhanced hADSCs differentiation into osteocytes compared with the control and pioglitazone-treated cells. Meanwhile, GTP upregulated protein and mRNA expression of RunX2 and Bmp2 compared to the control and GTP at 10 µg/mL significantly attenuated the decreased mRNA expression of Runx2 and Bmp2 by pioglitazone. Conclusions: The present study demonstrated that GTP possess a greater ability to facilitate osteogenesis and simultaneously inhibit hADSCs differentiation into the adipogenic lineage through upregulating the RUNX2-BMP2 mediated osteogenic pathway and suppressing PPARγ-induced signaling of adipogenesis. The findings of this study highlight that GTP may be a therapeutic intervention to combat osteoporosis associated obesity.


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