Effects of Epinephrine on Forearm Blood Flow and Metabolism in Man *

Baltzan, Marcel A.; Andres, Reubin; Cader, Gordon; Zierler, Kenneth L.

doi:10.1172/jci105130

Cited by 26 publications

(21 citation statements)

References 32 publications

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“…The effect of epinephrine on forearm blood flow agrees with a previous paper (34), and largely explains the increase in net leucine forearm balance. Since it is not known whether skeletal muscle blood flow in other parts of the body responds to epinephrine similarly to forearm, the overall contribution of muscle proteins to leucine flux cannot be determined from the present data.…”

Section: Discussionsupporting

confidence: 90%

Elevation of plasma epinephrine concentrations inhibits proteolysis and leucine oxidation in man via beta-adrenergic mechanisms.

Kraenzlin¹,

Keller²,

Keller³

et al. 1989

J. Clin. Invest.

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The role of elevated plasma epinephrine concentrations in the regulation of plasma leucine kinetics and the contribution of ,8-receptors were assessed in man. Epinephrine (50 ng/kg per min) was infused either alone or combined with propranolol (f,-blockade) into groups of six subjects fasted overnight; leucine flux, oxidation, and net plasma leucine forearm balance were determined during 180 min. Constant plasma insulin and glucagon concentrations were maintained in all studies by infusing somatostatin combined with insulin and glucagon replacements. Plasma leucine concentrations decreased from baseline during epinephrine infusion by 27±5 gmol/liter (P < 0.02) due to a 22±6% decrease in leucine flux (P < 0.05 vs. controls receiving saline) and to an increase in the metabolic clearance rate of leucine (P < 0.02). Leucine oxidation decreased by 36±8% (P < 0.01 vs. controls). fl-Blockade abolished the effect of epinephrine on leucine flux and oxidation. Net forearm release of leucine increased during epinephrine (P < 0.01), suggesting increased muscle proteolysis; the fall of total body leucine flux was therefore due to diminished proteolysis in nonmuscle tissues, such as splanchnic organs. Nonoxidative leucine disappearance as a parameter of protein synthesis was not significantly influenced by epinephrine. Plasma glucose and FFA concentrations increased via f,-adrenergic mechanisms (P < 0.001). The results suggest that elevation of plasma epinephrine concentrations similar to those observed in severe stress results in redistribution of body proteins and exerts a whole body protein-sparing effect; this may counteract catabolic effects of other hormones during severe stress.

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Section: Discussionsupporting

confidence: 90%

Elevation of plasma epinephrine concentrations inhibits proteolysis and leucine oxidation in man via beta-adrenergic mechanisms.

Kraenzlin¹,

Keller²,

Keller³

et al. 1989

J. Clin. Invest.

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“…During the hypertonic infusions, a gradually damping oscillation of blood flow was usually noted, probably due in part to the reciprocal relationship between blood flow and concentration of the vasoactive agent, as previously described (18). In most subjects, however, a reasonably steady-state blood flow was ultimately achieved during the hypertonic infusions.…”

Section: Resultssupporting

confidence: 61%

Response of the Limb Vascular Bed in Man to Intrabrachial Arterial Infusions of Hypertonic Dextrose or Hypertonic Sodium Chloride Solutions

Overbeck

Grega

1970

Circulation Research

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Infusions of hypertonic dextrose or NaCl solutions reduce resistance in several vascular beds of experimental animals. To study the response in man, 60 intrabrachial arterial jet infusions of hypertonic dextrose solution or hypertonic NaCl solution, each at 3 dose levels (1, 2, and 4 milliosmols/min), were made in 19 male student volunteers aged 21 to 29 years. Limb blood flow was measured by continuous infusion indicator-dilution, and vascular resistance calculated as mm Hg/ml flow/100 cm 3 limb vol/min. Measured increases in ipsilateral cephalic venous plasma osmolarity and serum dextrose and sodium concentrations during hypertonic infusions ranged from 7 to 30 milliosmols/ liter, 153 to 481 mg/100 ml and 4 to 19 mEq/liter, respectively. Measured limb venous blood hematocrit during hypertonic infusions was similar to that during control isotonic infusions. All 60 hypertonic infusions evoked an increase in limb blood flow and decrease in limb vascular resistance as compared to "resting" values during paired control isotonic NaCl infusions. There was a significant (P<.01) positive linear correlation between level of initial vascular resistance and magnitude of response to all hypertonic infusions. At each dose level, neither regression coefficient nor regression adjusted mean response to dextrose was significantly different from that to hypertonic NaCl (P>.05).The results of these studies indicate that the local vascular response to hypertonicity in the limb of man is a decrease in resistance, the magnitude of which is a function of the level of plasma osmolarity and the level of initial limb resistance. The steady-state responses to hypertonic dextrose are quantitatively similar to those to hypertonic NaCl. ADDITIONAL KEY WORDSsodium ion skeletal muscle skin viscosity vascular resistance wall-lumen ratio exercise hyperemia indicator-dilution hyperosmolar shock• Intra-arterial infusions of hypertonic dextrose or hypertonic NaCl solutions reduce resistance in several mammalian vascular beds; this response to increased plasmaFrom the

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“…Any system which improves arterial mixing should improve this reliability. It is also essential to detect satisfactory mixing in such response studies, especially in order to exclude anomalous high bifurcation of the brachial artery (2). The indicator dilution system described in the present paper offers both advantages.…”

Section: Discussionmentioning

confidence: 96%

“…If there is evidence of good mixing of indicator with limb blood, it may be inferred that an additional substance administered along with the indicator is equally well mixed (2). Such evidence of mixing is important in vascular response and metabolic studies, especially in cases of high bifurcation of the brachial artery, an anomaly occurring in about 20% of humans.…”

Section: Introductionmentioning

confidence: 99%

Continuous infusion indicator dilution measurement of limb blood flow and vascular response to magnesium sulfate in normotensive and hypertensive men

Overbeck¹,

Daugherty²,

Haddy³

1969

J. Clin. Invest.

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A B S T R A C T A constant infusion, indicator dilutiontechnique for blood flow measurements in the forearm and hand of man was tested and validated in vitro and in vivo. This technique employs jet injection to improve mixing of indicator with arterial blood. The mixing characteristics of the jet injection system were studied in vitro in tubing simulating the brachial artery of man. In addition, actual blood flows in the isolated pumpperfused forelimbs of five dogs were compared with constant infusion, indicator dilution calculated flows. Measurements were also made of mixing and of blood flow in the forearm and hand of man. The technique was used to compare forearm and hand vascular responses with constant intrabrachial arterial infusions of magnesium sulfate in 13 normotensive and 13 essential hypertensive men.In vitro and in vivo the jet injection system significantly improved mixing of indicator with blood, as compared with mixing produced by standard infusion techniques, without causing hemolysis. In 30 measurements in isolated, perfused dog forelimbs the correlation coefficient between actual and calculated blood flow was 0.992. Resting limb vascular resistance in the hypertensive group was significantly higher than in the normotensive group. Limb vascular resistance in all 26 men decreased in response to intrabrachial-arterial infusion of 0.25% magnesium sulfate (8 ml/min). Rate of infusion of Mg`+ was 0.162 mEq/min. There was a significant positive linear correlation between level of This work appeared in part as abstracts in Clin. Res. 13: 95, 1965, and Physiologist. 8: 247, 1965, and 9: 258, 1966 Dr. Overbeck's present address is Department of Physiology, Michigan State University, East Lansing, Mich. 48823.

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Effects of Epinephrine on Forearm Blood Flow and Metabolism in Man *

Cited by 26 publications

References 32 publications

Elevation of plasma epinephrine concentrations inhibits proteolysis and leucine oxidation in man via beta-adrenergic mechanisms.

Elevation of plasma epinephrine concentrations inhibits proteolysis and leucine oxidation in man via beta-adrenergic mechanisms.

Response of the Limb Vascular Bed in Man to Intrabrachial Arterial Infusions of Hypertonic Dextrose or Hypertonic Sodium Chloride Solutions

Continuous infusion indicator dilution measurement of limb blood flow and vascular response to magnesium sulfate in normotensive and hypertensive men

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