Morphological changes in the adipocyte during fat deposition and mobilization

Goldrick, R. B.

doi:10.1152/ajplegacy.1967.212.4.777

Cited by 239 publications

(90 citation statements)

References 4 publications

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“…Since adipocyte volume is determined by the content of intracellular lipids [30], we hypothesized that reduction of adipocyte volume in Atf4 −/− mice results from suppressed lipogenesis and increased mobilization of intracellular fat. Consistent with this possibility, protein levels of FAS and SREBP1c decreased significantly in WAT of Atf4 −/− mice, suggesting decreased lipogenesis.…”

Section: Discussionmentioning

confidence: 99%

ATF4 regulates lipid metabolism and thermogenesis

et al. 2010

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Activating transcription factor 4 (ATF4) has been shown to play key roles in many physiological processes. There are no reports, however, demonstrating a direct link between ATF4 and lipid metabolism. We noticed that Atf4-deficient mice are lean, suggesting a possible role for ATF4 in regulating lipid metabolism. The goal of our current study is to investigate the involvement of ATF4 in lipid metabolism and elucidate the underlying mechanisms. Studies using Atf4-deficient mice revealed increased energy expenditure, as measured by oxygen consumption. These mice also showed increases in lipolysis, expression of uncoupling protein 2 (UCP2) and β-oxidation genes and decreases in expression of lipogenic genes in white adipose tissue (WAT), suggesting increased utilization and decreased synthesis of fatty acids, respectively. Expression of UCP1, 2 and 3 was also increased in brown adipose tissue (BAT), suggesting increased thermogenesis. The effect of ATF4 deletion on expression of UCPs in BAT suggests that increased thermogenesis may underlie increased energy expenditure. Thus, our study identifies a possible new function for ATF4 in regulating lipid metabolism and thermogenesis.

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Section: Discussionmentioning

confidence: 99%

ATF4 regulates lipid metabolism and thermogenesis

et al. 2010

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“…When the mean cell diameter is known the mean cellular volume can ben calculated as suggested by Goldrick [12]. The mean cellular weight was calculated on the assumption that the density of fat cells is that of triolein [13].…”

Section: Methodsmentioning

confidence: 99%

Human adipose tissue in culture V. Studies on the metabolic effects of insulin

1976

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Summary.Specimens of human adipose tissue were cultured for one week with or without the addition of insulin. The basal as well as the noradrenaline-stimulated lipolysis were enhanced in the explants cultured with insulin, showing that the long-term effect of the hormone is lipolytic. However, an acute antilipolytic effect of insulin could be demonstrated in these explants in the subsequent short-term incubations. The basal rate of glucose incorporation into the lipids was enhanced in the explants cultured with insulin. When insulin was added in the short-term incubations these explants did not further respond to the hormone while this was the case with the explants cultured without insulin. Thus, it seems that prolonged exposure to insulin leads to a diminished acute effect of the hormone on glucose metabolism. However, the same explants responded to the antilipolytic effect showing that insulin was able to bind itself to the membrane. The activities of hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PDH), pyruvate kinase (PK) and lactate dehydrogenase (LDH) were increased in large fat cells both in freshly excised tissue and in the cultured explants. However, the activity of phosphofructokinase (PFK) did not correlate with the cell size. The presence of insulin during the culture period enhanced the activities of G6PDH, PK, and LDH, while this was not found for HK or PFK. The data thus suggest that the metabolic capacity of human fat cells is enhanced by long-term exposure to insulin. Although enzyme induction could be shown for G6PDH, PK and LDH it seems unlikely that this is of importance for the increased rates of glucose metabolism in these explants since the rate-limiting enzymes, HK and PFK, were not increased. Most probably, *Part of these data were presented at the First International Congress on Obesity in London, England on 9-11 October, 1974. then, this stimulating effect of insulin is exerted on the membrane and the rate of glucose transport.

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“…Isolated adipocytes were counted and the incubation buffer was added for the IL-6-release experiment. The cell volume was calculated using the Goldrick equation, 20 and the number of adipocytes was determined from the DiGirolamo equation. 21 IL-6 release IL-6 release from the adipocytes was studied in vitro, measured by the concentration of IL-6 released to the medium over 2 h, spontaneously and with two concentrations of epinephrine (500 and 2000 nmol l À1 ) to stimulate the IL-6 release.…”

Section: Adipocyte Isolationmentioning

confidence: 99%

Nutritional regulation of interleukin-6 release from adipocytes

et al. 2010

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Background and aims: As interleukin-6 (IL-6) has an important role in general metabolism with high circulating levels in obesity and other associated diseases, the factors regulating its synthesis and release have been considered possible therapeutic targets and have recently been studied. We examined the influence of three different diets, each having a different fatty acid compositionFsaturated, monounsaturated or polyunsaturated (coconut oil, olive oil and sunflower oil diets), on IL-6 release from rat adipocytes, and the interaction between diet and other regulatory factors of IL-6 release, such as epinephrine. Methods: A group of rats was assigned to one of the three different diets, each with a significantly different concentration of saturated, monounsaturated and polyunsaturated fatty acids. Samples were taken from the omental adipose tissue for measurement of the triacylglycerol fatty acid composition of the tissues and for adipocyte isolation. IL-6 release from adipocytes was measured in vitro, under nonstimulated conditions and also with two concentrations of epinephrine in the medium. Results: Animals fed with the olive oil diet showed lower values of IL-6 release with and without epinephrine stimulation. IL-6 release from adipocytes varied according to the diet, but not according to epinephrine dose. However, a significant interaction was found between the epinephrine dose and the diet in IL-6 release regulation. Conclusions: IL-6 release from adipocytes was markedly regulated by the dietary fatty acid composition, even under epinephrine stimulation, with lower values of IL-6 release in the olive oil diet. The study also showed that epinephrine regulation of IL-6 release was related to the diet.

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Morphological changes in the adipocyte during fat deposition and mobilization

Cited by 239 publications

References 4 publications

ATF4 regulates lipid metabolism and thermogenesis

ATF4 regulates lipid metabolism and thermogenesis

Human adipose tissue in culture V. Studies on the metabolic effects of insulin

Nutritional regulation of interleukin-6 release from adipocytes

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