Lipolysis and Lactate Production in Human Skeletal Muscle and Adipose Tissue following Glucose Ingestion

1998 ◽  
Vol 94 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Daniëlle A. J. M. Kerckhoffs ◽  
Peter Arner ◽  
Jan Bolinder
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Muscle Blood Flow ◽  
Lactate Production ◽  
Tissue Blood Flow ◽  
Oral Glucose ◽  
Glucose Load ◽  
Carbohydrate Ingestion ◽  
Glucose Ingestion

1. Using microdialysis, we compared lipolysis, as well as the production of lactate, in human adipose tissue and muscle after the ingestion of carbohydrate. 2. The absolute concentrations of glycerol and lactate were measured in subcutaneous adipose tissue, skeletal muscle and arterialized venous blood in eight normal subjects during basal conditions and 4 h after a 75 g oral glucose load. Nutritive blood flow in muscle and adipose tissue was monitored simultaneously with the microdialysis ethanol clearance technique. 3. At baseline, the concentrations of glycerol in adipose tissue and in muscle were about 7 times and about 2.5 times higher respectively than those in plasma. After glucose ingestion, the changes in glycerol concentrations differed significantly between the three compartments (P < 0.0001). In plasma and adipose tissue, the concentrations decreased rapidly and markedly, but returned to baseline levels after 4 h. In muscle, the decrease in glycerol was less pronounced and more protracted. 4. At baseline, the concentrations of lactate in muscle and in adipose tissue were about 3 times and about 1.5 times higher respectively than those in plasma. After the ingestion of glucose, the levels increased transiently in similar ways in muscle, adipose tissue and plasma. The differences in absolute lactate concentrations between the three compartments were maintained after the glucose load (P < 0.001). 5. Adipose tissue blood flow increased transiently after glucose ingestion, whereas muscle blood flow remained unchanged. 6. Both muscle and adipose tissue are a source of glycerol and lactate release during basal conditions and after glucose ingestion. The regulation of lactate production, but not of lipolysis, after carbohydrate ingestion is similar in the two tissues.

scholarly journals Total Forearm Blood Flow as an Indicator of Skeletal Muscle Blood Flow: Effect of Subcutaneous Adipose Tissue Blood Flow

1994 ◽  
Vol 87 (5) ◽  
pp. 559-566 ◽  
Author(s):  
E. E. Blaak ◽  
M. A. van Baak ◽  
G. J. Kemerink ◽  
M. T. W. Pakbiers ◽  
G. A. K. Heidendal ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Forearm Blood Flow ◽  
Muscle Blood Flow ◽  
Tissue Blood Flow ◽  
Adipose Tissue Blood Flow ◽  
Flow Through ◽  
Subcutaneous Adipose

1. In studying forearm skeletal muscle substrate exchange, an often applied method for estimating skeletal muscle blood flow is strain gauge plethysmography. A disadvantage of this method is that it only measures total blood flow through a segment of forearm and not the flow through the individual parts such as skin, adipose tissue and muscle. 2. In the present study the contribution of forearm subcutaneous adipose tissue blood flow to total forearm blood flow was evaluated in lean (% body fat 17.0 ± 2.2) and obese males (% body fat 30.9 ± 1.6) during rest and during infusion of the non-selective β-agonist isoprenaline. Measurements were obtained of body composition (hydrostatic weighing), forearm composition (magnetic resonance imaging) and of total forearm (venous occlusion plethysmography), skin (skin blood flow, laser Doppler), and subcutaneous adipose tissue blood flow (133Xe washout technique). 3. The absolute forearm area and the relative amount of fat (% of forearm area) were significantly higher in obese as compared to lean subjects, whereas the relative amounts of muscle and skin were similar. 4. During rest, the percentage contribution of adipose tissue blood flow to total forearm blood flow was significantly higher in lean compared with obese subjects (19 vs 12%, P < 0.05), whereas there were no differences in percentage contribution between both groups during isoprenaline infusion (10 vs 13%). Furthermore, the contribution of adipose tissue blood flow to total forearm blood flow was significantly lower during isoprenaline infusion than during rest in lean subjects (P < 0.05), whereas in the obese this value was similar during rest and during isoprenaline infusion. 5. In conclusion, although the overall contribution of adipose tissue blood flow to total forearm blood flow seems to be relatively small, the significance of this contribution may vary with degree of adiposity. Calculations on the contribution of adipose tissue blood flow and SBF to total forearm blood flow indicate that the contribution of non-muscular flow to total forearm blood flow may be of considerable importance and may amount in lean subjects to 35–50% of total forearm blood flow in the resting state.

Adipose tissue and skeletal muscle blood flow during mental stress

1989 ◽  
Vol 256 (1) ◽  
pp. E12-E18 ◽  
Author(s):  
B. Linde ◽  
P. Hjemdahl ◽  
U. Freyschuss ◽  
A. Juhlin-Dannfelt
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Mental Stress ◽  
Muscle Blood Flow ◽  
Venous Occlusion ◽  
Tissue Blood Flow ◽  
Beta Blockade ◽  
133Xe Clearance ◽  
Arterial Plasma

Mental stress [a modified Stroop color word conflict test (CWT)] increased adipose tissue blood flow (ATBF; 133Xe clearance) by 70% and reduced adipose tissue vascular resistance (ATR) by 25% in healthy male volunteers. The vasculatures of adipose tissue (abdomen as well as thigh), skeletal muscle of the calf (133Xe clearance), and the entire calf (venous occlusion plethysmography) responded similarly. Arterial epinephrine (Epi) and glycerol levels were approximately doubled by stress. beta-Blockade by metoprolol (beta 1-selective) or propranolol (nonselective) attenuated CWT-induced tachycardia similarly. Metoprolol attenuated stress-induced vasodilation in the calf and tended to do so in adipose tissue. Propranolol abolished vasodilation in the calf and resulted in vasoconstriction during CWT in adipose tissue. Decreases in ATR, but not in skeletal muscle or calf vascular resistances, were correlated to increases in arterial plasma glycerol (r = -0.42, P less than 0.05), whereas decreases in skeletal muscle and calf vascular resistances, but not in ATR, were correlated to increases in arterial Epi levels (r = -0.69, P less than 0.01; and r = -0.43, P less than 0.05, respectively). The results suggest that mental stress increases nutritive blood flow in adipose tissue and skeletal muscle considerably, both through the elevation of perfusion pressure and via vasodilatation. Withdrawal of vasoconstrictor nerve activity, vascular beta 2-adrenoceptor stimulation by circulating Epi, and metabolic mechanisms (in adipose tissue) may contribute to the vasodilatation.

No apparent suppression by insulin of in vivo skeletal muscle lipolysis in nonobese women

2002 ◽  
Vol 283 (2) ◽  
pp. E295-E301 ◽  
Author(s):  
Erik Moberg ◽  
Stefan Sjöberg ◽  
Eva Hagström-Toft ◽  
Jan Bolinder
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Insulin Infusion ◽  
Muscle Blood Flow ◽  
Tissue Blood Flow ◽  
Glycerol Release ◽  
Euglycemic Hyperinsulinemic Clamp ◽  
Flow Rates

To investigate the antilipolytic effect of insulin in skeletal muscle and adipose tissue in vivo, the rates of glycerol release from the two tissues were compared in 10 nonobese women during a two-step euglycemic hyperinsulinemic clamp. Tissue interstitial glycerol levels were determined by microdialysis, and tissue blood flow was assessed with the 133Xe clearance technique. Absolute rates of glycerol release were estimated according to Fick's principle. In both adipose tissue and muscle, glycerol levels decreased significantly already during the low insulin infusion rate. The fractional release of glycerol (difference between interstitial glycerol and arterialized venous plasma glycerol) was reduced by more than one-half in adipose tissue ( P < 0.0001) in response to insulin, whereas it remained unaltered in skeletal muscle. Muscle blood flow rates increased by 60% ( P < 0.02) during insulin infusion; in adipose tissue, blood flow rates did not change significantly in response to insulin. The basal rate of glycerol release from skeletal muscle amounted to ∼15% of that from adipose tissue. After insulin infusion, the rate of adipose tissue glycerol release was markedly suppressed, whereas in skeletal muscle the rate of glycerol mobilization did not change significantly in response to insulin. It is concluded that insulin does not inhibit the rate of lipolysis in skeletal muscle of nonobese women.

Effect of hand heating by a warm air box on O2 consumption of the contralateral arm

1992 ◽  
Vol 72 (6) ◽  
pp. 2364-2368 ◽  
Author(s):  
E. E. Blaak ◽  
M. A. Van Baak ◽  
K. P. Kempen ◽  
W. H. Saris
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Venous Blood ◽  
Oral Glucose ◽  
Glucose Load ◽  
Glucose Intake ◽  
Integrated Response

Arterialization of venous blood is often used in studying forearm metabolism. Astrup et al. [Am. J. Physiol. 255 (Endocrinol. Metab. 18): E572-E578, 1988] showed that heating of the hand by a warming blanket caused a redistribution of blood flow in the contralateral arm and thus introduced errors in forearm skeletal muscle flux calculations. The present study was undertaken to investigate how hand heating by a warm air box (60 degrees C) would affect metabolism and blood flow in the contralateral arm before and during 3 h after a glucose load. Eleven healthy volunteers (5 males, 6 females) underwent an oral glucose tolerance test (70 g) on two different occasions, one test with and one without heating of the contralateral hand, in random order. Heating the hand for 30 min before glucose intake did not affect skin temperature, rectal temperature, deep venous oxygen saturation, forearm blood flow, or oxygen consumption of forearm skeletal muscle. Although, after the glucose load, heating significantly increased forearm blood flow (P less than 0.05), the integrated response after glucose was not significantly different between control and heating experiments [67 +/- 43 and 117 +/- 41 (SE) ml/100 ml tissue]. With both conditions, there was an increase in skin temperature (P less than 0.001, integrated response control: 369 +/- 79 and heating: 416 +/- 203 degrees C) and oxygen consumption of forearm muscle (control: 290 +/- 73, P less than 0.05 and heating: 390 +/- 130 mumol/100 ml, P less than 0.05) after glucose intake. These responses did not significantly differ between the conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate ingestion, with transient endogenous insulinaemia, produces both sympathetic activation and vasodilatation in normal humans

2002 ◽  
Vol 102 (5) ◽  
pp. 523-529 ◽  
Author(s):  
Eleanor M. SCOTT ◽  
John P. GREENWOOD ◽  
Giovanni VACCA ◽  
John B. STOKER ◽  
Stephen G. GILBEY ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Sympathetic Activity ◽  
Healthy Subjects ◽  
Muscle Sympathetic Nerve Activity ◽  
Muscle Blood Flow ◽  
Carbohydrate Ingestion ◽  
Vascular Bed ◽  
Carbohydrate Meal

It has been shown that sustained insulin infusion causes an increase in sympathetic vasoconstrictor discharge but, despite this, also causes peripheral vasodilatation. The present study was designed to determine in healthy subjects the effect of ingestion of a carbohydrate meal, with its attendant physiological insulinaemia, on vascular resistance in and sympathetic vasoconstrictor discharge to the same vascular bed, and the relationship between these parameters. Fifteen healthy subjects were studied for 2h following ingestion of a carbohydrate meal. Calf vascular resistance was measured by venous occlusion plethysmography, and muscle sympathetic nerve activity was assessed by peroneal microneurography. Five of the subjects also ingested water on a separate occasion, as a control. Following the carbohydrate meal, the serum insulin concentration increased to 588±72pmol/l. This was associated with a 47% increase in skeletal muscle blood flow (P < 0.001), a 39% fall in vascular resistance (P < 0.001) and a 57% increase in sympathetic activity (P < 0.001). There was a significant correlation between the increase in insulin and the changes in blood flow, vascular resistance and sympathetic activity. In conclusion, we have shown that ingestion of a carbohydrate meal, with its attendant physiological insulinaemia, was associated with overriding skeletal muscle vasodilatation, despite an increase in sympathetic vasoconstrictor discharge to the same vascular bed. These mechanisms may be important in ensuring optimal glucose uptake and maintenance of blood pressure postprandially.

Adipose tissue function in the insulin-resistance syndrome

2005 ◽  
Vol 33 (5) ◽  
pp. 1045-1048 ◽  
Author(s):  
F. Karpe ◽  
G.D. Tan
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Blood Glucose Concentration ◽  
Insulin Resistance Syndrome ◽  
The Body ◽  
Tissue Blood Flow ◽  
Main Function ◽  
Adipose Tissue Blood Flow

Insulin resistance is often seen as a consequence of obesity and there are several possible links between adipose tissue function and insulin resistance determined in other organs such as skeletal muscle or liver. One such link is the regulation of NEFA (non-esterified fatty acid) delivery to the rest of the body. Simplistically, an expanded adipose tissue mass delivers more NEFA to the systemic circulation and these fatty acids compete for substrate utilization in skeletal muscle, which in turn reduces glucose utilization. This increases blood glucose concentration and provides the stimulus for increased insulin secretion and hyperinsulinaemia is a key feature of the insulin-resistance syndrome. However, there is abundant evidence that adipose tissue is exquisitely insulin sensitive and hyperinsulinaemia may therefore lead to a constant lipolytic inhibition in adipose tissue. Consequently, the main function of adipose tissue, to rapidly switch between fat uptake and fat release, will be hampered. Adipose tissue blood flow is the conveyor of signals and substrates to and from the adipose tissue. In healthy people adipose tissue blood flow is much enhanced by food intake, whereas in insulin-resistant subjects this response is blunted. This is another facet of unresponsiveness of adipose tissue in the insulin-resistance syndrome.

Contribution of BAT and skeletal muscle to thermogenesis induced by ephedrine in man

1985 ◽  
Vol 248 (5) ◽  
pp. E507-E515 ◽  
Author(s):  
A. Astrup ◽  
J. Bulow ◽  
J. Madsen ◽  
N. J. Christensen
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Local Temperature ◽  
Whole Body ◽  
Tissue Blood Flow ◽  
Muscle Oxygen ◽  
Brown Adipose ◽  
Muscle Oxygen Consumption

This investigation was performed to examine the role of brown adipose tissue (BAT) in thermogenesis induced by ephedrine in man. Light microscopy of biopsies from necropsy cases showed BAT to occur most frequently in the perirenal fat. Perirenal BAT thermogenesis was investigated in five lean men before and during stimulation with 1 mg ephedrine orally X kg body wt-1. Perirenal BAT thermogenesis was assessed by continuous measurements of local temperature and blood flow with the 133xenon clearance method. In the same study the effect of ephedrine on skeletal muscle oxygen consumption was estimated by measurements of leg blood flow and arteriovenous oxygen difference. The perirenal adipose tissue blood flow increased approximately twofold, whereas the local temperature increased approximately 0.1 degrees C on an average. Assuming that man possesses 700 g of BAT with a similar thermogenic capacity, this tissue contributed only 10 ml X min-1 to the 40 ml X min-1 increase in oxygen consumption in the subject whose perirenal BAT showed the most pronounced response to ephedrine. The leg oxygen consumption increased on an average 60% after ephedrine. By extrapolation of this value to whole body skeletal muscle, approximately 50% of the increase in oxygen consumption induced by ephedrine may take place in skeletal muscle. It is concluded that skeletal muscle is a tissue of importance with respect to the thermogenic effect of sympathomimetics in man, whereas the results do not support a major role for perirenal BAT.

scholarly journals Microdialysis: use in human exercise studies

1999 ◽  
Vol 58 (4) ◽  
pp. 913-917 ◽  
Author(s):  
Peter Arner
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Adipose Tissue ◽  
Brain Function ◽  
Water Soluble ◽  
Tissue Blood Flow ◽  
Microdialysis Probe ◽  
Peripheral Tissues

Microdialysis has been used for 25 years to study brain function in vivo. Recently, it has been developed for investigations on peripheral tissues. A microdialysis catheter is an artificial blood vessel system which can be placed in the extracellular space of various tissues such as adipose tissue and skeletal muscle in order to examine these tissues in situ. Molecules are collected from the tissue by the device and their true interstitial concentration can be estimated. Metabolically-active molecules can be delivered to the interstitial space through the microdialysis probe and their action on the tissue can be investigated locally without producing generalized effects. It is also possible to study local tissue blood flow with microdialysis by adding a flow marker (usually ethanol) to the microdialysis solvent. The microdialysis technique is particularly useful for studies of small and water-soluble molecules. A number of important observations on the in vivo regulation of lipolysis, carbohydrate metabolism and blood flow in human skeletal muscle and adipose tissue have been made recently using microdialysis.

Muscle Blood Flow and Mitochondrial Function: Influence of Aging

2002 ◽  
Vol 12 (3) ◽  
pp. 368-378 ◽  
Author(s):  
Ronald L. Terjung ◽  
Ryszard Zarzeczny ◽  
H.T. Yang
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Exercise Training ◽  
Muscle Blood Flow ◽  
The Elderly ◽  
Exchange Capacity ◽  
Oxygen Exchange ◽  
Whole Body ◽  
Tissue Blood Flow ◽  
Fiber Types

Skeletal muscle mitochondrial capacity (mito), tissue blood flow (BF) capacity, and oxygen exchange capacity (e.g., DO2) appear to be well matched. The different skeletal muscle fiber types and muscle remodeled, due to inactivity >(e.g., related to aging or disease) or exercise training, exhibit widely differing aerobics capacities (V̇O2max). Yet, there are remarkably coordinated alterations in these 3 parameters in each of these conditions. With such a balance, there is likely shared control among these parameters in limiting (V̇O2max) of muscle, although this is a matter of considerable debate. The reduction in aerobic capacity in elderly can be improved by submaximal aerobic exercise training; this is related to increases in muscle mitochondria concentration and capillarity, but probably not BF capacity, as this is limited by central cardiovascular function. Thus, exercise-induced biochemical adaptations and angiogenesis occur in the elderly. The increase in muscle capillarity likely contributes to the increased oxygen exchange capacity, typical of endurance type training. The increase in [mito] appears essential to realize the increased in muscle V̇O2max with training and amplifies the rate-limiting influence of the muscle’s oxygen exchange capacity. Further, vascular remodeling induced by exercise in the elderly could be effective at improving flow capacity, if limited by peripheral obstruction. Thus, the limits to aerobic function specific to aged muscle appear most influenced by inactivity, whereas central cardiovascular changes impact whole body performance. Some may consider the aged myocyte as a small, inactive, normal myocyte in need of activity!

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