PMID- 10956355
OWN - NLM
STAT- MEDLINE
DCOM- 20001019
LR  - 20171213
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 89
IP  - 3
DP  - 2000 Sep
TI  - beta-adrenergic blockade augments glucose utilization in horses during graded 
      exercise.
PG  - 1086-98
AB  - To examine the role of beta-adrenergic mechanisms in the regulation of endogenous 
      glucose (Glu) production [rate of appearance (R(a))] and utilization [rate of 
      disappearance (R(d))] and carbohydrate (CHO) metabolism, six horses completed 
      consecutive 30-min bouts of exercise at approximately 30% (Lo) and approximately 
      60% (Hi) of estimated maximum O(2) uptake with (P) and without (C) prior 
      administration of the beta-blocker propranolol (0.22 mg/kg iv). All horses 
      completed exercise in C; exercise duration in P was 49.9 +/- 1.2 (SE) min. Plasma 
      Glu was unchanged in C during Lo but increased progressively in Hi. In P, plasma 
      Glu rose steadily during Lo and Hi and was higher (P < 0.05) than in C throughout 
      exercise. Plasma insulin declined during exercise in P but not in C; 
      beta-blockade attenuated (P < 0.05) the rise in plasma glucagon and free fatty 
      acids and exaggerated the increases in epinephrine and norepinephrine. Glu R(a) 
      was 8.1 +/- 0.8 and 8.4 +/- 1.0 micromol. kg(-1). min(-1) at rest and 30.5 +/- 
      3.6 and 42.8 +/- 4.1 micromol. kg(-1). min(-1) at the end of Lo in C and P, 
      respectively. During Hi, Glu R(a) increased to 54.4 +/- 4.4 and 73.8 +/- 4.7 
      micromol. kg(-1). min(-1) in C and P, respectively. Similarly, Glu R(d) was 
      approximately 40% higher in P than in C during Lo (27.3 +/- 2.0 and 39.5 +/- 3.3 
      micromol. kg(-1). min(-1) in C and P, respectively) and Hi (37.4 +/- 2.6 and 61.5 
      +/- 5.3 micromol. kg(-1). min(-1) in C and P, respectively). beta-Blockade 
      augmented CHO oxidation (CHO(ox)) with a concomitant reduction in fat oxidation. 
      Inasmuch as estimated muscle glycogen utilization was similar between trials, the 
      increase in CHO(ox) in P was due to increased use of plasma Glu. We conclude that 
      beta-blockade increases Glu R(a) and R(d) and CHO(ox) in horses during exercise. 
      The increase in Glu R(d) under beta-blockade suggests that beta-adrenergic 
      mechanisms restrain Glu R(d) during exercise.
FAU - Geor, R J
AU  - Geor RJ
AD  - Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The 
      Ohio State University, Columbus, Ohio 43210, USA. rgeor@ker.com
FAU - Hinchcliff, K W
AU  - Hinchcliff KW
FAU - Sams, R A
AU  - Sams RA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Adrenergic beta-Antagonists)
RN  - 0 (Blood Glucose)
RN  - 0 (Blood Proteins)
RN  - 0 (Fatty Acids, Nonesterified)
RN  - 0 (Hormones)
RN  - 33X04XA5AT (Lactic Acid)
RN  - 9Y8NXQ24VQ (Propranolol)
RN  - IY9XDZ35W2 (Glucose)
RN  - PDC6A3C0OX (Glycerol)
RN  - X4W3ENH1CV (Norepinephrine)
RN  - YKH834O4BH (Epinephrine)
SB  - IM
MH  - Adrenergic beta-Antagonists/*pharmacology
MH  - Animals
MH  - Blood Glucose/analysis
MH  - Blood Proteins/analysis
MH  - Carbohydrate Metabolism
MH  - Epinephrine/metabolism
MH  - Fatty Acids, Nonesterified/blood
MH  - Female
MH  - Glucose/*metabolism
MH  - Glycerol/blood
MH  - Hematocrit
MH  - Hormones/blood
MH  - Horses/*metabolism
MH  - Kinetics
MH  - Lactic Acid/blood
MH  - Male
MH  - Motor Activity/*physiology
MH  - Norepinephrine/metabolism
MH  - Oxidation-Reduction
MH  - Propranolol/*pharmacology
MH  - Pulmonary Gas Exchange
EDAT- 2000/08/24 11:00
MHDA- 2000/10/21 11:01
CRDT- 2000/08/24 11:00
PHST- 2000/08/24 11:00 [pubmed]
PHST- 2000/10/21 11:01 [medline]
PHST- 2000/08/24 11:00 [entrez]
AID - 10.1152/jappl.2000.89.3.1086 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2000 Sep;89(3):1086-98. doi: 10.1152/jappl.2000.89.3.1086.