Document Detail


Acute glucocorticoid effects on glycogen utilization, O2 uptake, and endurance.
MedLine Citation:
PMID:  3366732     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study was undertaken to determine the effects of increased substrate availability (glycogen + plasma fatty acids) by glucocorticoids on energy metabolism during exercise to exhaustion. Female rats received a single subcutaneous injection of cortisol acetate (CA) (100 mg.kg body wt-1) 21 h before treadmill running (30.8 m/min). At the start of exercise in the CA-treated rats, plasma fatty acids and liver glycogen were increased by 40%. Glycogen levels were also increased by CA treatment in slow-twitch soleus (61%), fast-twitch white vastus (38%), and fast-twitch red vastus lateralis (85%) muscles. Exercise time to exhaustion was increased by CA treatment (114 +/- 5 vs. 95 +/- 6 min, P less than 0.05). During the exercise, total glycogen depletion was greater in the CA-treated than in the control animals, whereas estimated relative rates of carbohydrate utilization (R = 0.90) were similar. However, while running the CA-treated group consumed 11% more O2 than the controls (P less than 0.05). These results show that a single injection of glucocorticoids is capable of improving endurance. Yet the increased O2 uptake during exercise may have minimized the impact of the initial increased availability of carbohydrates and fatty acids in prolonging exercise capacity. This decreased running economy by the CA-treated runners may be secondary to alterations in energy production or utilization.
Authors:
E M Gorostiaga; S M Czerwinski; R C Hickson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  64     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 Mar 
Date Detail:
Created Date:  1988-06-23     Completed Date:  1988-06-23     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1098-106     Citation Subset:  IM; S    
Affiliation:
Department of Physical Education, University of Illinois, Chicago 60680.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Glucose / analysis
Body Weight
Carbohydrate Metabolism
Energy Metabolism
Fatty Acids, Nonesterified / blood
Female
Glucocorticoids / administration & dosage,  pharmacology*
Glycogen / metabolism*
Heart / anatomy & histology
Hydrocortisone / analogs & derivatives,  pharmacology
Lactates / blood
Liver / analysis,  anatomy & histology
Liver Glycogen / analysis
Muscles / analysis,  anatomy & histology
Myocardium / analysis
Organ Size
Oxygen Consumption*
Physical Exertion*
Rats
Rats, Inbred Strains
Grant Support
ID/Acronym/Agency:
K04-AM-01100/AM/NIADDK NIH HHS
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Glucocorticoids; 0/Lactates; 0/Liver Glycogen; 50-23-7/Hydrocortisone; 53187-58-9/hydrocortisone acetate; 9005-79-2/Glycogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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