Acute peripheral tissue effects of ghrelin on interstitial levels of glucose, glycerol, and lactate: a microdialysis study in healthy human subjects

2013 ◽  
Vol 304 (12) ◽  
pp. E1273-E1280 ◽  
Author(s):  
Esben Thyssen Vestergaard ◽  
Niels Møller ◽  
Jens Otto Lunde Jørgensen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Human Subjects ◽  
Systemic Exposure ◽  
Metabolic Effects ◽  
Controlled Study ◽  
Healthy Human ◽  
Adipose Tissues ◽  
Ghrelin Receptor ◽  
Basal Period

Ghrelin is a gut-derived peptide and an endogenous ligand for the ghrelin receptor. Intravenous infusion of ghrelin induces insulin resistance and hyperglycemia and increases circulating levels of nonesterified free fatty acids. Our objective was to investigate whether the metabolic effects are mediated directly by ghrelin in skeletal muscle and adipose (peripheral and central) tissues. Ten healthy men (24.9 ± 1.3 yr) received 300 min of supraphysiological ghrelin administration by microdialysis catheters in skeletal muscle and adipose tissues in a randomized, single-blind, and placebo-controlled study. Microdialysis perfusates were analyzed every 30 min for glucose, glycerol, and lactate during both a basal period and a hyperinsulinemic euglycemic clamp. The primary outcome measures were interstitial concentrations of glucose, glycerol, and lactate in skeletal muscle and adipose tissues. Interstitial concentrations of glucose were similar in skeletal muscle, peripheral, and central adipose tissue in the basal period. During hyperinsulinemia, interstitial concentrations of glucose in skeletal muscle decreased in response to ghrelin exposure [2.84 ± 0.25 (ghrelin) vs. 3.06 ± 0.26 mmol/l (placebo), P = 0.04]. Ghrelin exposure did not impact on interstitial concentrations of glycerol and lactate. We conclude that ghrelin administration into skeletal muscle decreases interstitial concentrations of glucose during euglycemic hyperinsulinemia, which is indicative of increased insulin sensitivity without any effects on interstitial glycerol levels in either muscle or adipose tissue. These data contrast with the metabolic effects of ghrelin observed after systemic exposure and suggest the existence of a second messenger that remains to be identified.

Thermogenic response to epinephrine in the forearm and abdominal subcutaneous adipose tissue

1992 ◽  
Vol 263 (5) ◽  
pp. E850-E855 ◽  
Author(s):  
L. Simonsen ◽  
J. Bulow ◽  
J. Madsen ◽  
N. J. Christensen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Glucose Uptake ◽  
Subcutaneous Adipose Tissue ◽  
Whole Body ◽  
Epinephrine Infusion ◽  
Basal Period ◽  
Subcutaneous Adipose

Whole body energy expenditure, thermogenic and metabolic changes in the forearm, and intercellular glucose concentrations in subcutaneous adipose tissue on the abdomen determined by microdialysis were measured during epinephrine infusion in healthy subjects. After a control period, epinephrine was infused at rates of 0.2 and 0.4 nmol.kg-1 x min-1. Whole body resting energy expenditure was 4.36 +/- 0.56 (SD) kJ/min. Energy expenditure increased to 5.14 +/- 0.74 and 5.46 +/- 0.79 kJ/min, respectively (P < 0.001), during the epinephrine infusions. Respiratory exchange ratio was 0.80 +/- 0.04 in the resting state and did not change. Local forearm oxygen uptake was 3.9 +/- 1.3 mumol.100 g-1 x min-1 in the basal period. During epinephrine infusion, it increased to 5.8 +/- 2.1 (P < 0.03) and 7.5 +/- 2.3 mumol.100 g-1 x min-1 (P < 0.001). Local forearm glucose uptake was 0.160 +/- 0.105 mumol.100 g-1 x min-1 and increased to 0.586 +/- 0.445 and 0.760 +/- 0.534 mumol.100 g-1 x min-1 (P < 0.025). The intercellular glucose concentration in the subcutaneous adipose tissue on the abdomen was equal to the arterial concentration in the basal period but did not increase as much during infusion of epinephrine, indicating glucose uptake in adipose tissue in this condition. If it is assumed that forearm skeletal muscle is representative for the average skeletal muscle, it can be calculated that on average 40% of the enhanced whole body oxygen uptake induced by infusion of epinephrine is taking place in skeletal muscle. It is proposed that adipose tissue may contribute to epinephrine-induced thermogenesis.

scholarly journals Beige Fat, Adaptive Thermogenesis, and Its Regulation by Exercise and Thyroid Hormone

Biology ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 57 ◽  
Author(s):  
Kevin J. Phillips
Keyword(s):  
Adipose Tissue ◽  
Thyroid Hormone ◽  
Metabolic Effects ◽  
Adipose Tissues ◽  
Beige Adipocyte ◽  
Adaptive Thermogenesis ◽  
Beige Adipocytes ◽  
Beige Fat ◽  
Beige Cells ◽  
Adipocyte Development

While it is now understood that the proper expansion of adipose tissue is critically important for metabolic homeostasis, it is also appreciated that adipose tissues perform far more functions than simply maintaining energy balance. Adipose tissue performs endocrine functions, secreting hormones or adipokines that affect the regulation of extra-adipose tissues, and, under certain conditions, can also be major contributors to energy expenditure and the systemic metabolic rate via the activation of thermogenesis. Adipose thermogenesis takes place in brown and beige adipocytes. While brown adipocytes have been relatively well studied, the study of beige adipocytes has only recently become an area of considerable exploration. Numerous suggestions have been made that beige adipocytes can elicit beneficial metabolic effects on body weight, insulin sensitivity, and lipid levels. However, the potential impact of beige adipocyte thermogenesis on systemic metabolism is not yet clear and an understanding of beige adipocyte development and regulation is also limited. This review will highlight our current understanding of beige adipocytes and select factors that have been reported to elicit the development and activation of thermogenesis in beige cells, with a focus on factors that may represent a link between exercise and ‘beiging’, as well as the role that thyroid hormone signaling plays in beige adipocyte regulation.

Results of a Placebo-Controlled Study of the Metabolic Effects of the Addition of Metformin to Sulfonylurea-Treated Patients: Evidence for a central role of adipose tissue

Diabetes Care ◽  
1997 ◽  
Vol 20 (12) ◽  
pp. 1863-1869 ◽  
Author(s):  
F. Abbasi ◽  
V. Kamath ◽  
A. A. Rizvi ◽  
M. Carantoni ◽  
Y. D. I. Chen ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Metabolic Effects ◽  
Controlled Study

scholarly journals Mitochondria in White, Brown, and Beige Adipocytes

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Miroslava Cedikova ◽  
Michaela Kripnerová ◽  
Jana Dvorakova ◽  
Pavel Pitule ◽  
Martina Grundmanova ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Energy Metabolism ◽  
Oxygen Radicals ◽  
Adipocyte Differentiation ◽  
Nonshivering Thermogenesis ◽  
Adipose Tissues ◽  
White Adipocytes ◽  
Beige Adipocytes ◽  
Colour Appearance

Mitochondria play a key role in energy metabolism in many tissues, including cardiac and skeletal muscle, brain, liver, and adipose tissue. Three types of adipose depots can be identified in mammals, commonly classified according to their colour appearance: the white (WAT), the brown (BAT), and the beige/brite/brown-like (bAT) adipose tissues. WAT is mainly involved in the storage and mobilization of energy and BAT is predominantly responsible for nonshivering thermogenesis. Recent data suggest that adipocyte mitochondria might play an important role in the development of obesity through defects in mitochondrial lipogenesis and lipolysis, regulation of adipocyte differentiation, apoptosis, production of oxygen radicals, efficiency of oxidative phosphorylation, and regulation of conversion of white adipocytes into brown-like adipocytes. This review summarizes the main characteristics of each adipose tissue subtype and describes morphological and functional modifications focusing on mitochondria and their activity in healthy and unhealthy adipocytes.

scholarly journals Digestive and metabolic effects of potato and maize fibres in human subjects

1997 ◽  
Vol 77 (1) ◽  
pp. 33-46 ◽  
Author(s):  
C. Cherbut ◽  
A.-C. Aube ◽  
N. Mekki ◽  
C. Dubois ◽  
D. Lairon ◽  
...  
Keyword(s):  
Transit Time ◽  
Binding Capacity ◽  
Human Subjects ◽  
Chemical Properties ◽  
Basal Diet ◽  
Metabolic Effects ◽  
Healthy Human ◽  
Water Binding ◽  
Blood Concentrations

The physiological effects of dietary fibres in humans are due to their physico-chemical properties. However, it is difficult to predict these effects simply by measuring certain characteristicsin vitro. Studies in human subjects are still required to assess the effectiveness of new substrates. The aim of the present study in healthy human subjects was to evaluate the effects of two novel fibres, potato (PF) and maize (MF), on fasting and postprandial blood concentrations of carbohydrate and lipid metabolites as well as on stool ouput and transit time. The chemical composition, water-binding capacity (WBC) and fermentative properties of the fibres were also characterized in order to determine their possible involvement in digestive and metabolic effects. Stools, as well as breath and blood samples, were collected after consumption for 1 month of either a basal diet (control) or a basal diet supplemented with fibre (15 g/d). MF resisted fermentation better than PF and had lower digestibility. However, both fibres increased faecal output of dry matter, neutral sugars and water. There was an inverse relationship between stool weight and orofaecal transit time, although only MF significantly reduced transit time. Orocaecal transit was lengthened by PF, probably because of its high WBC. PF ingestion also decreased postprandial plasma levels of total and esterified cholesterol but had no effect on fasting concentrations. In contrast, MF lowered fasting cholesterolaemia and increased free:esterified cholesterol. These particular physiological and fermentative properties suggest that PF and MF would be suitable ingredients in a healthy diet.

scholarly journals Phaseolus vulgaris extract affects glycometabolic and appetite control in healthy human subjects

2012 ◽  
Vol 109 (10) ◽  
pp. 1789-1795 ◽  
Author(s):  
Angela Spadafranca ◽  
Samuele Rinelli ◽  
Antonella Riva ◽  
Paolo Morazzoni ◽  
Paolo Magni ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Human Subjects ◽  
Postprandial Glucose ◽  
Controlled Study ◽  
Appetite Control ◽  
Healthy Human ◽  
Double Blind ◽  
C Peptide ◽  
Ghrelin Secretion ◽  
Desire To Eat

Extracts of Phaseolus vulgaris (beans) are known to reduce glycaemia and food intake in rodents and humans. The present study evaluated the effects of a new, standardised and purified P. vulgaris extract (PVE), when employed as a supplement in a mixed balanced meal (60 % carbohydrates, 25 % lipids and 15 % protein), on glycometabolic and appetite control. To this end, a randomised, double-blind, placebo-controlled study was performed in twelve volunteers. Plasma glucose, insulin, C-peptide, ghrelin and satiety sensation ratings were assessed at baseline and during 3 h after meal consumption associated with PVE (100 mg) or placebo. Compared with placebo, PVE consumption resulted in lower increments in glucose (+15·4 (sem 5·4) v. 26·1 (sem 7·3) %, P= 0·04 at 30 min), insulin (+981 (sem 115) v. 1325 (sem 240) %, P= 0·04 between 45 and 120 min) and C-peptide (+350 (sem 27) v. 439 (sem 30) %, P= 0·04 between 30 and 90 min). In the first 2 h, plasma ghrelin decreased similarly in both groups but did not rebound as in placebo thereafter (P= 0·04). Correspondingly, satiety sensation in the third hour was significantly reduced in the placebo but not in the PVE condition. PVE induced a lower desire to eat than placebo (P= 0·02) over the 3 h. In conclusion, PVE supplementation reduced postprandial glucose, insulin and C-peptide excursions, suppressed ghrelin secretion and affected satiety sensations, inducing a lower desire to eat. These results support that further studies are needed to prove the concept of employing PVE as a supplement in mixed balanced meals in obese, glucose-intolerant and diabetic subjects.

Assessment of transcapillary glucose exchange in human skeletal muscle and adipose tissue

2003 ◽  
Vol 285 (2) ◽  
pp. E241-E251 ◽  
Author(s):  
Werner Regittnig ◽  
Martin Ellmerer ◽  
Günter Fauler ◽  
Gerald Sendlhofer ◽  
Zlatko Trajanoski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Human Skeletal Muscle ◽  
Human Subjects ◽  
Quadriceps Muscle ◽  
Model Parameters ◽  
Interstitial Glucose ◽  
Normal Human ◽  
Dynamic Relationships ◽  
Subcutaneous Adipose

We studied the kinetics of glucose exchange between plasma and interstitial fluid (ISF) in human skeletal muscle and adipose tissue under fasting conditions. Five normal human subjects received an intravenous [6,6-2H2]glucose infusion in a prime-continuous fashion. During the tracer infusion, the open-flow microperfusion technique was employed to frequently sample ISF from quadriceps muscle and subcutaneous adipose tissue. The tracer glucose kinetics observed in muscle and adipose tissue ISF were found to be well described by a capillary-tissue exchange model. As a measure of transcapillary glucose exchange efficiency, the 95% equilibrium time was calculated from the identified model parameters. This time constant was similar for skeletal muscle and adipose tissue (28.6 ± 3.2 vs. 26.8 ± 3.6 min; P = 0.60). Furthermore, we found that the (total) interstitial glucose concentration was significantly lower ( P < 0.01) in muscle (3.32 ± 0.46 mmol/l) and adipose tissue (3.51 ± 0.17 mmol/l) compared with arterialized plasma levels (5.56 ± 0.13 mmol/l). Thus the observed gradients and dynamic relationships between plasma and ISF glucose in muscle and adipose tissue provide evidence that transcapillary exchange of glucose is limited in these two tissues under fasting conditions.

scholarly journals Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial

2011 ◽  
Vol 108 (2) ◽  
pp. 315-326 ◽  
Author(s):  
Inger Ottestad ◽  
Gjermund Vogt ◽  
Kjetil Retterstøl ◽  
Mari C. Myhrstad ◽  
John-Erik Haugen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Fish Oil ◽  
Human Subjects ◽  
Controlled Study ◽  
Healthy Human ◽  
Significant Difference ◽  
Healthy Human Subjects ◽  
Markers Of Oxidative Stress ◽  
Randomised Controlled

Intake of fish oil reduces the risk of CHD and CHD deaths. Marine n-3 fatty acids (FA) are susceptible to oxidation, but to our knowledge, the health effects of intake of oxidised fish oil have not previously been investigated in human subjects. The aim of the present study was to investigate markers of oxidative stress, lipid peroxidation and inflammation, and the level of plasma n-3 FA after intake of oxidised fish oil. In a double-blinded randomised controlled study, healthy subjects (aged 18–50 years, n 54) were assigned into one of three groups receiving capsules containing either 8 g/d of fish oil (1·6 g/d EPA+DHA; n 17), 8 g/d of oxidised fish oil (1·6 g/d EPA+DHA; n 18) or 8 g/d of high-oleic sunflower oil (n 19). Fasting blood and morning spot urine samples were collected at weeks 0, 3 and 7. No significant changes between the different groups were observed with regard to urinary 8-iso-PGF2α; plasma levels of 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and α-tocopherol; serum high sensitive C-reactive protein; or activity of antioxidant enzymes in erythrocytes. A significant increase in plasma level of EPA+DHA was observed in both fish oil groups, but no significant difference was observed between the fish oil groups. No changes in a variety of in vivo markers of oxidative stress, lipid peroxidation or inflammation were observed after daily intake of oxidised fish oil for 3 or 7 weeks, indicating that intake of oxidised fish oil may not have unfavourable short-term effects in healthy human subjects.

Sign in / Sign up

Export Citation Format

Share Document