PMID- 8828686
OWN - NLM
STAT- MEDLINE
DCOM- 19961218
LR  - 20171213
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 81
IP  - 1
DP  - 1996 Jul
TI  - A reduced lactate mass explains much of the glycogen sparing associated with 
      training.
PG  - 362-7
AB  - Endurance training is associated with glycogen (Gly) sparing, generally 
      attributed to less carbohydrate (CHO) oxidation. However, untrained individuals 
      commit a greater fraction of CHO to lactate (La), accounting for a portion of the 
      Gly "spared." We examined the effects of training (running 1 h/day at 30 m/min up 
      an 8 degrees grade) on whole body CHO distribution and oxidation. Female Long 
      Evans rats (n = 27) were assigned to control (Untr) and trained (Tr) groups. Two 
      days before the experiment, animals were chronically catheterized. On the day of 
      the experiment, animals ran for 20 min at a speed of 28 m/min and were killed 
      with an overdose of pentobarbital sodium injection while running. Whole carcasses 
      were then promptly freeze-clamped with a liquid N2-cooled press. Whole body 
      carcass powder was assayed for La, Gly, and glucose. Resting whole body values 
      were not different between groups (La = 0.78 +/- 0.06 vs. 0.83 +/- 0.07, Gly = 
      4.46 +/- 0.62 vs. 3.77 +/- 0.35, glucose = 0.19 +/- 0.07 vs. 0.23 +/- 0.09 
      mmol/body for Tr and Untr rats, respectively). However, postexercise La was 
      higher in Untr vs. Tr group (2.01 +/- 0.28 vs. 1.13 +/- 0.09 mmol/body), and Gly 
      was lower in the Untr vs. Tr rats (1.58 +/- 0.25 vs. 3.42 +/- 0.43 mmol/body). 
      Similarly, Untr animals displayed higher epinephrine levels than Tr at the end of 
      the exercise bout (4.9 +/- 1.0 vs. 1.7 +/- 0.4 ng/ml). Differences between groups 
      in La and glucose masses (postexercise minus rest data) accounted for 60% of the 
      Gly differences. Gly spared from oxidation and replaced by increased fat 
      oxidation only accounted for 40% of the differences in Gly levels between Tr and 
      Untr animals. We conclude that untrained mammals commit a significant portion of 
      their CHO pool to La, which accounts for almost one-half of the apparent Gly 
      spared during moderate-intensity exercise in the trained state.
FAU - Crowley, M A
AU  - Crowley MA
AD  - Exercise and Sport Research Institute, Arizona State University, Tempe 
      85287-0404, USA.
FAU - Willis, W T
AU  - Willis WT
FAU - Matt, K S
AU  - Matt KS
FAU - Donovan, C M
AU  - Donovan CM
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 (Blood Glucose)
RN  - 33X04XA5AT (Lactic Acid)
RN  - 9005-79-2 (Glycogen)
RN  - IY9XDZ35W2 (Glucose)
RN  - X4W3ENH1CV (Norepinephrine)
RN  - YKH834O4BH (Epinephrine)
SB  - IM
MH  - Animals
MH  - Blood Glucose/metabolism
MH  - Body Weight/physiology
MH  - Epinephrine/blood
MH  - Exercise Test
MH  - Female
MH  - Glucose/metabolism
MH  - Glucose Clamp Technique
MH  - Glycogen/*metabolism
MH  - Lactic Acid/*metabolism
MH  - Norepinephrine/blood
MH  - Oxygen Consumption
MH  - Physical Conditioning, Animal
MH  - Physical Endurance/physiology
MH  - Physical Exertion/*physiology
MH  - Rats
MH  - Rest/physiology
EDAT- 1996/07/01 00:00
MHDA- 1996/07/01 00:01
CRDT- 1996/07/01 00:00
PHST- 1996/07/01 00:00 [pubmed]
PHST- 1996/07/01 00:01 [medline]
PHST- 1996/07/01 00:00 [entrez]
AID - 10.1152/jappl.1996.81.1.362 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 1996 Jul;81(1):362-7. doi: 10.1152/jappl.1996.81.1.362.