Associations of plasma ghrelin, leptin and cholecystokinin (CCK) with sensations of hunger and fullness during manipulations of energy balance by meal size, exercise and intravenous nutrient replacement.

Administration of metformin is known to reduce both body weight and food intake. Although the hypothalamus is recognized as a critical regulator of energy balance and body weight, there is currently no evidence for an effect of metformin in the hypothalamus. Therefore, we sought to determine the central action of metformin on energy balance and body weight, as well as its potential involvement with key hypothalamic energy sensors, including adenosine monophosphate-activated protein kinase (AMPK) and S6 kinase (S6K). We used meal pattern analysis and a conditioned taste aversion (CTA) test and measured energy expenditure in C56BL/6 mice administered metformin (0, 7.5, 15, or 30 μg) into the third ventricle (I3V). Furthermore, we I3V-administered either control or metformin (30 μg) and compared the phosphorylation of AMPK and S6K in the mouse mediobasal hypothalamus. Compared with the control, I3V administration of metformin decreased body weight and food intake in a dose-dependent manner and did not result in CTA. Furthermore, the reduction in food intake induced by I3V administration of metformin was accomplished by decreases in both nocturnal meal size and number. Compared with the control, I3V administration of metformin significantly increased phosphorylation of S6K at Thr389 and AMPK at Ser485/491 in the mediobasal hypothalamus, while AMPK phosphorylation at Thr172 was not significantly altered. Moreover, I3V rapamycin pretreatment restored the metformin-induced anorexia and weight loss. These results suggest that the reduction in food intake induced by the central administration of metformin in the mice may be mediated by activation of S6K pathway.

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Endogenous leptin receptor signaling in the medial nucleus tractus solitarius affects meal size and potentiates intestinal satiation signals

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00205.2012 ◽

2012 ◽

Vol 303 (4) ◽

pp. E496-E503 ◽

Cited By ~ 34

Author(s):

Scott E. Kanoski ◽

Shiru Zhao ◽

Douglas J. Guarnieri ◽

Ralph J. DiLeone ◽

Jianqun Yan ◽

...

Keyword(s):

Energy Balance ◽

Food Intake ◽

Leptin Receptor ◽

Nucleus Tractus Solitarius ◽

Balance Control ◽

Area Postrema ◽

Meal Size ◽

Receptor Signaling ◽

Medial Nucleus ◽

Neuronal Systems

Leptin receptor (LepRb) signaling in the hindbrain is required for energy balance control. Yet the specific hindbrain neurons and the behavioral processes mediating energy balance control by hindbrain leptin signaling are unknown. Studies here employ genetic [adeno-associated virally mediated RNA interference (AAV-RNAi)] and pharmacological methodologies to specify the neurons and the mechanisms through which hindbrain LepRb signaling contributes to the control of food intake. Results show that AAV-RNAi-mediated LepRb knockdown targeting a region encompassing the mNTS and area postrema (AP) (mNTS/AP LepRbKD) increases overall cumulative food intake by increasing the size of spontaneous meals. Other results show that pharmacological hindbrain leptin delivery and RNAi-mediated mNTS/AP LepRb knockdown increased and decreased the intake-suppressive effects of intraduodenal nutrient infusion, respectively. These meal size and intestinally derived signal amplification effects are likely mediated by LepRb signaling in the mNTS and not the AP, since 4th icv and mNTS parenchymal leptin (0.5 μg) administration reduced food intake, whereas this dose did not influence food intake when injected into the AP. Overall, these findings deepen the understanding of the distributed neuronal systems and behavioral mechanisms that mediate the effects of leptin receptor signaling on the control of food intake.

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Ghrelin/leptin ratio tracks energy balance, while ratings of appetite track only meal size and give paradoxical values to exercise energy expenditure

Appetite ◽

10.1016/j.appet.2008.04.043 ◽

2008 ◽

Vol 51 (2) ◽

pp. 355

Author(s):

K.T. Borer ◽

E. Wuorinen ◽

C. Burant

Keyword(s):

Energy Balance ◽

Energy Expenditure ◽

Meal Size ◽

Exercise Energy Expenditure

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The feeding microstructure of male and female mice

PLoS ONE ◽

10.1371/journal.pone.0246569 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246569

Author(s):

Yakshkumar Dilipbhai Rathod ◽

Mauricio Di Fulvio

Keyword(s):

Energy Balance ◽

Energy Intake ◽

Negative Energy ◽

Meal Size ◽

Negative Energy Balance ◽

Dependent Manner ◽

Eating Time ◽

Male And Female ◽

Female Mice ◽

Old Females

The feeding pattern and control of energy intake in mice housed in groups are poorly understood. Here, we determined and quantified the normal feeding microstructure of social male and female mice of the C57BL/6J genetic background fed a chow diet. Mice at 10w, 20w and 30w of age showed the expected increase in lean and fat mass, being the latter more pronounced and variable in males than in females. Under ad libitum conditions, 20w and 30w old females housed in groups showed significantly increased daily energy intake when adjusted to body weight relative to age-matched males. This was the combined result of small increases in energy intake during the nocturnal and diurnal photoperiods of the day without major changes in the circadian pattern of energy intake or spontaneous ambulatory activity. The analysis of the feeding microstructure suggests sex- and age-related contributions of meal size, meal frequency and intermeal interval to the control of energy intake under stable energy balance, but not under negative energy balance imposed by prolonged fasting. During the night, 10-20w old females ate less frequently bigger meals and spent more time eating them resulting in reduced net energy intake relative to age-matched males. In addition, male and female mice at all ages tested significantly shortened the intermeal interval during the first hours of re-feeding in response to fasting without affecting meal size. Further, 20-30w old males lengthened their intermeal interval as re-feeding time increased to reach fed-levels faster than age-matched females. Collectively, our results suggest that the physiological mechanisms controlling meal size (satiation) and the non-eating time spent between meals (satiety) during stable or negative energy balance are regulated in a sex- and age-dependent manner in social mice.

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Effects of Ambipolar Diffusion on Prominence Thread Models

International Astronomical Union Colloquium ◽

10.1017/s0252921100025513 ◽

1994 ◽

Vol 144 ◽

pp. 315-321 ◽

Cited By ~ 1

Author(s):

M. G. Rovira ◽

J. M. Fontenla ◽

J.-C. Vial ◽

P. Gouttebroze

Keyword(s):

Energy Balance ◽

Transition Region ◽

Ambipolar Diffusion ◽

Line Profiles ◽

Balance Equations ◽

Model Calculations ◽

Partial Frequency ◽

Frequency Redistribution ◽

Partial Frequency Redistribution ◽

Theoretical Structure

AbstractWe have improved previous model calculations of the prominence-corona transition region including the effect of the ambipolar diffusion in the statistical equilibrium and energy balance equations. We show its influence on the different parameters that characterize the resulting prominence theoretical structure. We take into account the effect of the partial frequency redistribution (PRD) in the line profiles and total intensities calculations.

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Influence of Magnetic Fields on Solar Hydrodynamics: Experimental Results

International Astronomical Union Colloquium ◽

10.1017/s025292110005329x ◽

1977 ◽

Vol 36 ◽

pp. 143-180 ◽

Cited By ~ 10

Author(s):

J.O. Stenflo

Keyword(s):

Solar Activity ◽

Energy Balance ◽

Magnetic Fields ◽

Solar Atmosphere ◽

General Problem ◽

Solar Rotation ◽

Active Regions ◽

Physical Conditions ◽

Dynamic Phenomena

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.

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