10 results on '"Ho-Palma, Ana Cecilia"'
Search Results
2. Higher lactate production from glucose in cultured adipose nucleated stromal cells than for rat adipocytes.
- Author
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Rotondo, Floriana, Ho-Palma, Ana-Cecilia, Romero, María del Mar, Remesar, Xavier, Fernández-López, José Antonio, and Alemany, Marià
- Subjects
- *
STROMAL cells , *WHITE adipose tissue , *FREE fatty acids , *GLUCOSE , *ANAEROBIC metabolism - Abstract
White adipose tissue (WAT) nucleated stromal cells (NSC) play important roles in regulation, defense, regeneration and metabolic control. In WAT sites, the proportions and functions of NSC change under diverse physiological or pathologic conditions. We had previously observed the massive anaerobic wasting of glucose to lactate and glycerol in rat epididymal adipocytes. To test site variability, and whether the adipocyte extensive anaerobic metabolism of glucose was found in NSC, we analyzed, in parallel, subcutaneous, mesenteric and epididymal WAT of male adult Wistar rats. Adipocytes and NSC fractions, were isolated, counted and incubated (as well as red blood cells: RBC) with glucose, and their ability to use glucose and produce lactate, glycerol, and free fatty acids was measured. Results were computed taking into account the number of cells present in WAT samples. Cell numbers were found in proportions close to 1:13:100 (respectively, for adipocytes, NSC and RBC) but their volumes followed a reversed pattern: 7,500:10:1. When counting only non-fat cell volumes, the ratios changed dramatically to 100:10:1. RBC contribution to lactate production was practically insignificant. In most samples, NSC produced more lactate than adipocytes did, but only adipocytes secreted glycerol (and fatty acids in smaller amounts). Glucose consumption was also highest in NSC, especially in mesenteric WAT. The heterogeneous NSC showed a practically anaerobic metabolism (like that already observed in adipocytes). Thus, NSC quantitative production of lactate markedly contributed (i.e. more than adipocytes) to WAT global use (wasting) of glucose. We also confirmed that glucose-derived glycerol is exclusively produced by adipocytes. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
3. Effect of sex on glucose handling by adipocytes isolated from rat subcutaneous, mesenteric and perigonadal adipose tissue.
- Author
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Rotondo, Floriana, Ho-Palma, Ana Cecilia, Remesar, Xavier, Fernández-López, José Antonio, del Mar Romero, María, and Alemany, Marià
- Subjects
ADIPOSE tissues ,WHITE adipose tissue ,CATABOLITE repression ,FAT cells ,FATTY acids ,RATS - Abstract
Background. Adult rat epididymal adipocytes are able to convert large amounts of glucose to lactate and glycerol. However, fatty acid efflux is much lower than that expected from glycerol levels if they were the product of lipolysis. Use of glucose for lipogenesis is limited, in contrast with the active glycolysis-derived lactate (and other 3-carbon substrates). In this study, we analyzed whether white adipose tissue (WAT) site and sex affect these processes. Methods. Mature adipocytes from perigonadal, mesenteric and subcutaneous WAT of female and male rats were isolated, and incubated with 7 or 14mMglucose during 1 or 2 days. Glucose consumption, metabolite efflux and gene expression of glycolytic and lipogenesis-related genes were measured. Results. The effects of medium initial glucose concentration were minimal on most parameters studied. Sex-induced differences that were more extensive; however, the most marked, distinct, effects between WAT sites, were dependent on the time of incubation. In general, the production of lactate was maintained during the incubation, but glycerol release rates increased with time, shifting from a largely glycolytic origin to its triacylglycerol (TAG) lipolytic release. Glycerol incorporation was concurrent with increased TAG turnover: lipolytic glycerol was selectively secreted, while most fatty acids were recycled again into TAG. Fatty acid efflux increased with incubation, but was, nevertheless, minimal compared with that of glycerol. Production of lactate and glycerol from glucose were maximal in mesenteric WAT. Discussion. Female rats showed a higher adipocyte metabolic activity than males. In mesenteric WAT, gene expression (and substrate efflux) data suggested that adipocyte oxidation of pyruvate to acetyl-CoA was higher in females than in males, with enhanced return of oxaloacetate to the cytoplasm for its final conversion to lactate. WAT site differences showed marked tissue specialization-related differences. Use of glucose for lipogenesis was seriously hampered over time, when TAG turnover-related lipolysis was activated. We postulate that these mechanisms may help decrease glycaemia and fat storage, producing, instead, a higher availability of less-regulated 3-carbon substrates, used for energy elsewhere. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. Use of 14C-glucose by primary cultures of mature rat epididymal adipocytes. Marked release of lactate and glycerol, but limited lipogenesis in the absence of external stimuli.
- Author
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Ho-Palma, Ana Cecilia, Rotondo, Floriana, Romero, María del Mar, Fernández-López, José Antonio, Remesar, Xavier, and Alemany, Marià
- Subjects
- *
GLUCOSE , *GLYCERIN , *FAT cells - Abstract
White adipose tissue can metabolize large amounts of glucose to glycerol and lactate. We quantitatively traced glucose label to lactate, glycerol and fats in primary cultures of mature rat epididymal adipocytes. Cells were incubated with 7/14 mM 14C-glucose for 24/48 h. Medium metabolites and the label in them and in cells' components were measured. Gene expression analysis was done using parallel incubations. Glucose concentration did not affect lactate efflux and most parameters. Glycerol efflux increased after 24 h, coinciding with arrested lipogenesis. Steady production of lactate was maintained in parallel to glycerogenesis. Changes in adipocyte metabolism were paralleled by gene expression. Glucose use for lipogenesis was minimal, and stopped (24 h-onwards) when glycerol efflux increased because of triacylglycerol turnover. Lactate steady efflux showed that anaerobic glycolysis was the main adipocyte source of energy. We can assume that adipose tissue may play a quantitatively significant effect on glycaemia, returning 3C fragments thus minimizing lipogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
5. A method for the measurement of lactate, glycerol and fatty acid production from 14C-glucose in primary cultures of rat epididymal adipocytes.
- Author
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Ho-Palma, Ana Cecilia, Rotondo, Floriana, Romero, María del Mar, Memmolo, Serena, Remesar, Xavier, Fernández-López, José Antonio, and Alemany, Marià
- Published
- 2016
- Full Text
- View/download PDF
6. Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis.
- Author
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Toro, Pau, Rotondo, Floriana, Ho-Palma, Ana Cecilia, Romero, María del Mar, Alemany, Marià, Remesar, Xavier, and Fernández-López, José Antonio
- Abstract
Under normoxic conditions, adipocytes in primary culture convert huge amounts of glucose to lactate and glycerol. This "wasting" of glucose may help to diminish hyperglycemia. Given the importance of insulin in the metabolism, we have studied how it affects adipocyte response to varying glucose levels, and whether the high basal conversion of glucose to 3-carbon fragments is affected by insulin. Rat fat cells were incubated for 24 h in the presence or absence of 175 nM insulin and 3.5, 7, or 14 mM glucose; half of the wells contained
14 C-glucose. We analyzed glucose label fate, medium metabolites, and the expression of key genes controlling glucose and lipid metabolism. Insulin increased both glucose uptake and the flow of carbon through glycolysis and lipogenesis. Lactate excretion was related to medium glucose levels, which agrees with the purported role of disposing excess (circulating) glucose. When medium glucose was low, most basal glycerol came from lipolysis, but when glucose was high, release of glycerol via breakup of glycerol-3P was predominant. Although insulin promotes lipogenesis, it also limited the synthesis of glycerol-3P from glucose and its incorporation into acyl-glycerols. We assume that this is a mechanism of adipose tissue defense to avoid crippling fat accumulation which has not yet been described. [ABSTRACT FROM AUTHOR]- Published
- 2019
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- View/download PDF
7. Insulin Controls Triacylglycerol Synthesis through Control of Glycerol Metabolism and Despite Increased Lipogenesis.
- Author
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Ho-Palma AC, Toro P, Rotondo F, Romero MDM, Alemany M, Remesar X, and Fernández-López JA
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- Animals, Male, Rats, Rats, Wistar, Glycerol metabolism, Insulin pharmacology, Lipogenesis physiology, Triglycerides biosynthesis
- Abstract
Under normoxic conditions, adipocytes in primary culture convert huge amounts of glucose to lactate and glycerol. This "wasting" of glucose may help to diminish hyperglycemia. Given the importance of insulin in the metabolism, we have studied how it affects adipocyte response to varying glucose levels, and whether the high basal conversion of glucose to 3-carbon fragments is affected by insulin. Rat fat cells were incubated for 24 h in the presence or absence of 175 nM insulin and 3.5, 7, or 14 mM glucose; half of the wells contained
14 C-glucose. We analyzed glucose label fate, medium metabolites, and the expression of key genes controlling glucose and lipid metabolism. Insulin increased both glucose uptake and the flow of carbon through glycolysis and lipogenesis. Lactate excretion was related to medium glucose levels, which agrees with the purported role of disposing excess (circulating) glucose. When medium glucose was low, most basal glycerol came from lipolysis, but when glucose was high, release of glycerol via breakup of glycerol-3P was predominant. Although insulin promotes lipogenesis, it also limited the synthesis of glycerol-3P from glucose and its incorporation into acyl-glycerols. We assume that this is a mechanism of adipose tissue defense to avoid crippling fat accumulation which has not yet been described.- Published
- 2019
- Full Text
- View/download PDF
8. Use of 14 C-glucose by primary cultures of mature rat epididymal adipocytes. Marked release of lactate and glycerol, but limited lipogenesis in the absence of external stimuli.
- Author
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Ho-Palma AC, Rotondo F, Romero MDM, Fernández-López JA, Remesar X, and Alemany M
- Subjects
- Animals, Carbon Radioisotopes, Cells, Cultured, Male, Rats, Rats, Wistar, Adipocytes cytology, Adipocytes metabolism, Epididymis cytology, Glucose metabolism, Glycerol metabolism, Lactic Acid metabolism, Lipogenesis
- Abstract
White adipose tissue can metabolize large amounts of glucose to glycerol and lactate. We quantitatively traced glucose label to lactate, glycerol and fats in primary cultures of mature rat epididymal adipocytes. Cells were incubated with 7/14 mM
14 C-glucose for 24/48 h. Medium metabolites and the label in them and in cells' components were measured. Gene expression analysis was done using parallel incubations. Glucose concentration did not affect lactate efflux and most parameters. Glycerol efflux increased after 24 h, coinciding with arrested lipogenesis. Steady production of lactate was maintained in parallel to glycerogenesis. Changes in adipocyte metabolism were paralleled by gene expression. Glucose use for lipogenesis was minimal, and stopped (24 h-onwards) when glycerol efflux increased because of triacylglycerol turnover. Lactate steady efflux showed that anaerobic glycolysis was the main adipocyte source of energy. We can assume that adipose tissue may play a quantitatively significant effect on glycaemia, returning 3C fragments thus minimizing lipogenesis.- Published
- 2018
- Full Text
- View/download PDF
9. Glycerol is synthesized and secreted by adipocytes to dispose of excess glucose, via glycerogenesis and increased acyl-glycerol turnover.
- Author
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Rotondo F, Ho-Palma AC, Remesar X, Fernández-López JA, Romero MDM, and Alemany M
- Subjects
- Animals, Biological Transport, Carbon Radioisotopes analysis, Cells, Cultured, Glycolysis, Isotope Labeling, Lactic Acid metabolism, Lipolysis, Male, Rats, Wistar, Time Factors, Adipocytes metabolism, Glucose metabolism, Glycerides metabolism, Glycerol metabolism
- Abstract
White adipose tissue (WAT) produces large amounts of lactate and glycerol from glucose. We used mature epididymal adipocytes to analyse the relative importance of glycolytic versus lipogenic glycerol in adipocytes devoid of external stimuli. Cells were incubated (24/48 h) with 7/14 mM glucose; half of the wells contained
14 C-glucose. We analysed glucose label fate, medium metabolites, and the expression of key genes coding for proteins controlling glycerol metabolism. The effects of initial glucose levels were small, but time of incubation increased cell activity and modified its metabolic focus. The massive efflux of lactate was uniform with time and unrelated to glucose concentration; however, glycerol-3P synthesis was higher in the second day of incubation, being largely incorporated into the glycerides-glycerol fraction. Glycerophosphatase expression was not affected by incubation. The stimulation of glycerogenic enzymes' expression was mirrored in lipases. The result was a shift from medium glycolytic to lipolytic glycerol released as a consequence of increased triacylglycerol turnover, in which most fatty acids were recycled. Production of glycerol seems to be an important primary function of adipocytes, maintained both by glycerogenesis and acyl-glycerol turnover. Production of 3C fragments may also contribute to convert excess glucose into smaller, more readily usable, 3C metabolites.- Published
- 2017
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10. Quantitative analysis of rat adipose tissue cell recovery, and non-fat cell volume, in primary cell cultures.
- Author
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Rotondo F, Romero MD, Ho-Palma AC, Remesar X, Fernández-López JA, and Alemany M
- Abstract
Background: White adipose tissue (WAT) is a complex, diffuse, multifunctional organ which contains adipocytes, and a large proportion of fat, but also other cell types, active in defense, regeneration and signalling functions. Studies with adipocytes often require their isolation from WAT by breaking up the matrix of collagen fibres; however, it is unclear to what extent adipocyte number in primary cultures correlates with their number in intact WAT, since recovery and viability are often unknown., Experimental Design: Epididymal WAT of four young adult rats was used to isolate adipocytes with collagenase. Careful recording of lipid content of tissue, and all fraction volumes and weights, allowed us to trace the amount of initial WAT fat remaining in the cell preparation. Functionality was estimated by incubation with glucose and measurement of glucose uptake and lactate, glycerol and NEFA excretion rates up to 48 h. Non-adipocyte cells were also recovered and their sizes (and those of adipocytes) were measured. The presence of non-nucleated cells (erythrocytes) was also estimated., Results: Cell numbers and sizes were correlated from all fractions to intact WAT. Tracing the lipid content, the recovery of adipocytes in the final, metabolically active, preparation was in the range of 70-75%. Cells showed even higher metabolic activity in the second than in the first day of incubation. Adipocytes were 7%, erythrocytes 66% and other stromal (nucleated cells) 27% of total WAT cells. However, their overall volumes were 90%, 0.05%, and 0.2% of WAT. Non-fat volume of adipocytes was 1.3% of WAT., Conclusions: The methodology presented here allows for a direct quantitative reference to the original tissue of studies using isolated cells. We have also found that the "live cell mass" of adipose tissue is very small: about 13 µL/g for adipocytes and 2 µL/g stromal, plus about 1 µL/g blood (the rats were killed by exsanguination). These data translate (with respect to the actual "live cytoplasm" size) into an extremely high metabolic activity, which make WAT an even more significant agent in the control of energy metabolism., Competing Interests: The authors declare there are no competing interests.
- Published
- 2016
- Full Text
- View/download PDF
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