Leptin: The Tale of an Obesity Gene

José, F.; Sinha, Madhur K.; Kolaczynski, Jerzy W.; Zhang, Pei Li; Considine, Robert V.

doi:10.2337/diab.45.11.1455

Cited by 918 publications

(675 citation statements)

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“…The adipocyte hormone leptin is suggested to be involved in the hypothalamic control of energy expenditure, body mass, fattening and food intake (Caro et al 1996;Boyer et al 1997). However, in the present study there were no significant differences in the pre-experimental post-absorptive (day 1) concentrations of leptin between May and November (Fig.…”

Section: Discussioncontrasting

confidence: 67%

“…Adaptations to periods of food deprivation require adjustments in fat deposition, metabolic rate, hormonal regulation and in the mobilisation of fuel substrates. The adipocyte hormone, leptin, is a peripheral signal involved in the regulation of body adiposity, food intake and metabolic rate in mammals (Caro et al 1996). It has also been suggested that it is a negative feedback signal to seasonal increases in appetite and body mass gain in arctic ground squirrels (Spermophilus parryii plesius; Boyer et al 1997).…”

Section: Introductionmentioning

confidence: 99%

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Effects of season, food deprivation and re-feeding on leptin, ghrelin and growth hormone in arctic foxes ( Alopex lagopus ) on Svalbard, Norway

Fuglei

Mustonen

Nieminen

2004

Journal of Comparative Physiology B: Biochemical, Systemic, and

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The arctic fox (Alopex lagopus) is a mediumsized predator of the high Arctic experiencing extreme seasonal fluctuations in food availability, photoperiod and temperature. In this study, the plasma leptin, ghrelin and growth hormone (GH) concentrations of male arctic foxes were determined during a food deprivation period of 13 days and the subsequent recovery in November and May. Leptin, ghrelin and GH were present in arctic fox plasma in amounts comparable to other carnivores. The plasma leptin concentrations did not react to food deprivation unlike in humans and rodents. However, the leptin levels increased during re-feeding as an indicator of increasing energy reserves. The relatively high ghrelin-leptin ratio, decrease in the plasma ghrelin concentration, an increase in the circulating GH concentrations and the observed negative correlation between plasma ghrelin and free fatty acid levels during fasting suggest that these hormones take part in the weight-regulation and energy metabolism of this species by increasing fat utilisation during food deprivation. The results strengthen the hypothesis that the actions of these weight-regulatory hormones are species-specific and depend on seasonality and the life history of the animals.

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Section: Discussioncontrasting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Effects of season, food deprivation and re-feeding on leptin, ghrelin and growth hormone in arctic foxes ( Alopex lagopus ) on Svalbard, Norway

Fuglei

Mustonen

Nieminen

2004

Journal of Comparative Physiology B: Biochemical, Systemic, and

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“…Adipose tissue is now recognized as an endocrine organ that secretes many cytokines and growth factors. 4,5 For example, several reports have demonstrated that adipocytes secrete tumor necrosis factor alpha, 6 resistin, 7 plasminogen activator inhibitor-1 (PAI-1), 8 leptin 9 and angiotensinogen. 10,11 Vascular endothelial growth factor (VEGF) is an angiogenetic growth factor, which is secreted by rat adipose tissue ex vivo.…”

Section: Introductionmentioning

confidence: 99%

Hepatocyte growth factor secreted by cultured adipocytes promotes tube formation of vascular endothelial cells in vitro

et al. 2006

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Objective: Adipose tissue is closely associated with angiogenesis, but the mechanisms are not fully understood. Some of the adipocyte-derived cytokines are hypothesized to play an important role in angiogenesis. We evaluated tube formation of human umbilical vascular endothelial cells (HUVECs) cultured in type I collagen gel when overlaid with the supernatant of 3T3-L1 cell culture, and expression of tube-forming factor(s) in 3T3-L1 cells with or without pioglitazone. We also studied plasma growth factor levels in patients with type 2 diabetes mellitus treated with pioglitazone. Results and methods: The supernatant of 3T3-L1 cells increased tube formation of HUVECs by 9.03-fold of control. Reverse transcription-polymerase chain reaction showed that hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) mRNA were expressed in 3T3-L1 cells. Western blot analysis also demonstrated HGF and VEGF protein expression. When 3T3-L1 cells were treated with 100 nM small interfering RNAs (siRNAs) for HGF, the HGF mRNA and protein were suppressed. The VEGF mRNA and protein in the cells were also suppressed by siRNA for VEGF. The supernatant of 3T3-L1 cells treated with HGF siRNA suppressed tube formation of HUVECs by 61% compared with the supernatant of cells treated with control siRNA. Addition of VEGF siRNA resulted in no significant changes. The supernatant conditioned with pioglitazone further promoted the tube formation. Pioglitazone enhanced HGF mRNA expression in 3T3-L1 cells. After 12 weeks of pioglitazone treatment, the changes of plasma HGF levels in patients treated with pioglitazone were significantly higher than those in control. Conclusion: These results suggest that HGF secreted from 3T3-L1 cells may be the major factor regulating the tube formation, and agents that enhance the differentiation of adipocytes may promote tube formation of HUVECs mediated by HGF secreted by adipocytes.

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“…Under physiological conditions, the circulating leptin levels lie within the low nanomolar range [36]. Consequently, the rstb.royalsocietypublishing.org Phil.…”

Section: A Key Role For Phosphatase and Tensin Homologue In The Regulmentioning

confidence: 99%

Leptin regulation of hippocampal synaptic function in health and disease

Irving

Harvey

2014

Phil. Trans. R. Soc. B

102

100

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The endocrine hormone leptin plays a key role in regulating food intake and body weight via its actions in the hypothalamus. However, leptin receptors are highly expressed in many extra-hypothalamic brain regions and evidence is growing that leptin influences many central processes including cognition. Indeed, recent studies indicate that leptin is a potential cognitive enhancer as it markedly facilitates the cellular events underlying hippocampal-dependent learning and memory, including effects on glutamate receptor trafficking, neuronal morphology and activity-dependent synaptic plasticity. However, the ability of leptin to regulate hippocampal synaptic function markedly declines with age and aberrant leptin function has been linked to neurodegenerative disorders such as Alzheimer's disease (AD). Here, we review the evidence supporting a cognitive enhancing role for the hormone leptin and discuss the therapeutic potential of using leptin-based agents to treat AD.

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Leptin: The Tale of an Obesity Gene

Cited by 918 publications

References 0 publications

Effects of season, food deprivation and re-feeding on leptin, ghrelin and growth hormone in arctic foxes ( Alopex lagopus ) on Svalbard, Norway

Effects of season, food deprivation and re-feeding on leptin, ghrelin and growth hormone in arctic foxes ( Alopex lagopus ) on Svalbard, Norway

Hepatocyte growth factor secreted by cultured adipocytes promotes tube formation of vascular endothelial cells in vitro

Leptin regulation of hippocampal synaptic function in health and disease

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