Lipogenesis and insulin sensitivity of single fat cells*

Gliemann, Jørgen; Vinten, J.; Vølund, Aa.

doi:10.1113/jphysiol.1974.sp010449

Cited by 37 publications

(27 citation statements)

References 16 publications

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“…Considering that caveolae have been implicated in lipid transport and metabolism (25), the present finding of a constant density of caveolar proteins in the plasma membrane and cytoplasmic rim is consistent with a recent report on uptake of fluorescent fatty acids, which was also constant when expressed per cellular area and thus increased with cell size (41). It could be noted in this connection that earlier published data from our laboratory on cellular lipogenesis from glucose in single adipocytes have likewise showed near proportionality between lipogenesis and cell surface (9).…”

Section: Discussionsupporting

confidence: 92%

“…Techniques from the early 1970s took advantage of differences in flotation rates of small and large adipocytes (1) or fractionation of adipocytes by filtering the adipocyte suspension through nylon mesh screens of different pore size (13) subdividing isolated fat cells in populations with different mean diameters. Those studies showed that both basal and insulin-stimulated glucose metabolism increase with cell size so that the insulin fold response and insulin sensitivity were the same for all cells in a biopsy (1,9,13).…”

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confidence: 98%

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Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy

Hulstrøm

Prats

Vinten

2013

American Journal of Physiology-Cell Physiology

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Hulstrøm V, Prats C, Vinten J. Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy. Am J Physiol Cell Physiol 304: C1168 -C1175, 2013. First published April 10, 2013 doi:10.1152/ajpcell.00273.2012.-Caveolae are abundant in adipocytes and are involved in the regulation of lipid accumulation, which is the main volume determinant of these cells. We have developed and applied a confocal microscopic technique for measuring individual cellular expression of the caveolar proteins cavin-1 and caveolin-1 along with the size of individual adipocytes. The technique was applied on collagenase isolated adipocytes from ad libitum fed Sprague-Dawley rats of different age (4-26 wk) and weight (103-629 g). We found that cellular expression of caveolar proteins was variable (SD of log expression in the range from 0.25 to 0.65). Regression analysis of protein expression on adipocyte size revealed that the expression of the caveolar proteins cavin-1 and caveolin-1 on adipocytes from individual rats was tightly related to adipocyte cell surface area (mean coefficient of regression was 0.83 for cavin and 0.77 for caveolin), indicating that caveolar density was the same in membranes from all cells within a biopsy. This intrinsic relation remained unchanged with animal age, but adipocytes from animals with increasing age showed a decrease in mean expression of caveolar proteins per unit cell surface. The different relation between adipocyte size and cellular expression levels of caveolar proteins within and between individuals of different age shows that caveolar density is an age-sensitive characteristic of adipocytes.adipocyte cell size; caveolae; cavin-1; caveolin-1 MEAN ADIPOCYTE SIZE AND ADIPOSE tissue cellularity increases with age in sedentary inbred rodents. Furthermore, it is well documented that obesity is associated with decreased insulin sensitivity of fat cells (6, 40). Many research groups have studied the relationship between a number of metabolic parameters and adipocyte size (8,11,15,35). Early studies of possible functional impacts of adipocyte size were carried out on pools of cells from animals of different age or weight and consequently different mean cell size (29,30,36). Interpretation of data from such studies is difficult since it is not possible to dissociate an influence of cell size per se from an effect of interindividual factors correlated to cell size during aging. To analyze whether the functions of the fat cell vary with adipocyte size per se, it is necessary to separate fat cells of different sizes in the same biopsy. Techniques from the early 1970s took advantage of differences in flotation rates of small and large adipocytes (1) or fractionation of adipocytes by filtering the adipocyte suspension through nylon mesh screens of different pore size (13) subdividing isolated fat cells in populations with different mean diameters. Those studies showed that both basal and insulin-stimulated glucose metabolism increase with cell size so that the insulin fold response...

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Section: Discussionsupporting

confidence: 92%

mentioning

confidence: 98%

Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy

Hulstrøm

Prats

Vinten

2013

American Journal of Physiology-Cell Physiology

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“…Transport rates were established using L-arabinose, 2-deoxyglucose, and 3-O-methyl glucose and an original oil flotation technique allowing short-term (i.e., within seconds) measurements (71,111). A number of studies using isolated rat adipocytes focused on the relationships between insulin binding, glucose transport, and glucose oxidation, taking into account several physiological states of the animals (e.g., fasting, spontaneous obesity, insulin resistance, diabetes, and aging) (129,130,257,258,375). When cAMP levels were lowered with antilipolytic agents (insulin, nicotinic acid, or clofibrate), rates of glucose transport were increased.…”

Section: Isolated Fat Cell and Discovery Of Hexose And Fatty Acid Tramentioning

confidence: 99%

Historical perspectives in fat cell biology: the fat cell as a model for the investigation of hormonal and metabolic pathways

Lafontan

2012

American Journal of Physiology-Cell Physiology

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Lafontan M. Historical perspectives in fat cell biology: the fat cell as a model for the investigation of hormonal and metabolic pathways. Am J Physiol Cell Physiol 302: C327-C359, 2012. First published September 7, 2011; doi:10.1152/ajpcell.00168.2011.-For many years, there was little interest in the biochemistry or physiology of adipose tissue. It is now well recognized that adipocytes play an important dynamic role in metabolic regulation. They are able to sense metabolic states via their ability to perceive a large number of nervous and hormonal signals. They are also able to produce hormones, called adipokines, that affect nutrient intake, metabolism and energy expenditure. The report by Rodbell in 1964 that intact fat cells can be obtained by collagenase digestion of adipose tissue revolutionized studies on the hormonal regulation and metabolism of the fat cell. In the context of the advent of systems biology in the field of cell biology, the present seems an appropriate time to look back at the global contribution of the fat cell to cell biology knowledge. This review focuses on the very early approaches that used the fat cell as a tool to discover and understand various cellular mechanisms. Attention essentially focuses on the early investigations revealing the major contribution of mature fat cells and also fat cells originating from adipose cell lines to the discovery of major events related to hormone action (hormone receptors and transduction pathways involved in hormonal signaling) and mechanisms involved in metabolite processing (hexose uptake and uptake, storage, and efflux of fatty acids). Dormant preadipocytes exist in the stroma-vascular fraction of the adipose tissue of rodents and humans; cell culture systems have proven to be valuable models for the study of the processes involved in the formation of new fat cells. Finally, more recent insights into adipocyte secretion, a completely new role with major metabolic impact, are also briefly summarized. history; adipocytes; insulin action; 3T3-L1 cells; glucose transport; fatty acids; lipolysis; catecholamines; preadipocytes SINCE THE EARLIEST TIMES, attention has been directed toward fat-related questions. It is currently accepted that the ability to store fat in adipose tissue was a major advantage for survival during cold winters and periods of food shortage for our "primitive" hunter ancestors. However, in modern societies, with increased food availability and nutritional efficacy, excessive fat deposition is frequently associated with degenerative or metabolic diseases. As early as 1901, life insurance companies noted that excess weight, particularly around the abdomen, was linked to reduced life expectancy. The risk was confirmed in the seminal studies of Vague (366) in Marseilles, who established the importance of abdominal (central) obesity in conferring excess mortality. The health hazard of obesity is not considered in the present review, which, rather, focuses on adipose tissue and adipocytes.

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“…The literature regarding the relationship between cell size and lipogenesis is not consistent. In vitro experiments in rats and human cells report increased DNL in large cells [5,6], whereas other rat studies have reported decreased insulin-enhanced DNL from glucose [7,8]. Caution should be exercised in extrapolating results from rat studies, as the lipogenic capacity of adipose tissue in humans is lower than in rats [9].…”

Section: Introductionmentioning

confidence: 99%

Markers of de novo lipogenesis in adipose tissue: associations with small adipocytes and insulin sensitivity in humans

et al. 2009

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Aims/hypothesis Previous studies have shown relationships between fatty acid ratios in adipose tissue triacylglycerol (TG), adipocyte size and measures of insulin sensitivity. We hypothesised that variations in adipose tissue de novo lipogenesis (DNL) in relation to adiposity might explain some of these observations. Methods In a cross-sectional study, subcutaneous abdominal adipose tissue biopsies from 59 people were examined in relation to fasting and post-glucose insulin sensitivity. Adipocyte size, TG fatty acid composition and mRNA expression of lipogenic genes were determined. Results We found strong positive relationships between adipose tissue TG content of the fatty acids myristic acid (14:0) and stearic acid (18:0) with insulin sensitivity (HOMA model) (p<0.01 for each), and inverse relationships with adipocyte size (p<0.01, p<0.05, respectively).

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Lipogenesis and insulin sensitivity of single fat cells*

Cited by 37 publications

References 16 publications

Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy

Adipocyte size and cellular expression of caveolar proteins analyzed by confocal microscopy

Historical perspectives in fat cell biology: the fat cell as a model for the investigation of hormonal and metabolic pathways

Markers of de novo lipogenesis in adipose tissue: associations with small adipocytes and insulin sensitivity in humans

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