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Acute glucocorticoid effects on glycogen utilization, O2 uptake, and endurance.
J Appl Physiol (1985). 1988 Mar; 64(3):1098-106.JA

Abstract

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+Show Affiliations

Department of Physical Education, University of Illinois, Chicago 60680.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

3366732

Citation

Gorostiaga, E M., et al. "Acute Glucocorticoid Effects On Glycogen Utilization, O2 Uptake, and Endurance." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 64, no. 3, 1988, pp. 1098-106.
Gorostiaga EM, Czerwinski SM, Hickson RC. Acute glucocorticoid effects on glycogen utilization, O2 uptake, and endurance. J Appl Physiol (1985). 1988;64(3):1098-106.
Gorostiaga, E. M., Czerwinski, S. M., & Hickson, R. C. (1988). Acute glucocorticoid effects on glycogen utilization, O2 uptake, and endurance. Journal of Applied Physiology (Bethesda, Md. : 1985), 64(3), 1098-106.
Gorostiaga EM, Czerwinski SM, Hickson RC. Acute Glucocorticoid Effects On Glycogen Utilization, O2 Uptake, and Endurance. J Appl Physiol (1985). 1988;64(3):1098-106. PubMed PMID: 3366732.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Acute glucocorticoid effects on glycogen utilization, O2 uptake, and endurance. AU - Gorostiaga,E M, AU - Czerwinski,S M, AU - Hickson,R C, PY - 1988/3/1/pubmed PY - 1988/3/1/medline PY - 1988/3/1/entrez SP - 1098 EP - 106 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J Appl Physiol (1985) VL - 64 IS - 3 N2 - 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. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/3366732/Acute_glucocorticoid_effects_on_glycogen_utilization_O2_uptake_and_endurance_ DB - PRIME DP - Unbound Medicine ER -