Faculty Collaboration Database

Contractile and fatigue properties of thyrotoxic rat skeletal muscle. Muscle Nerve 1984;7(6):470-7

Date

07/01/1984

Pubmed ID

6543899

DOI

10.1002/mus.880070609

Scopus ID

2-s2.0-0021269917 (requires institutional sign-in at Scopus site)   27 Citations

Abstract

The effects of thyrotoxicosis on the contractile properties and development of muscle fatigue in the slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles were examined in rats given 3 mg of L-thyroxine and 1 mg of L-triiodothyronine per kilogram of diet for 6 weeks. The hormone treatment produced significant decreases in the contraction time, one-half relaxation time, and twitch tension in the SOL, while the peak rate of tension development (+ dP/dt) and decline (- dP/dt) in this muscle were elevated. Additionally, the force-frequency curve was shifted to the right and, thus, resembled the curve of a normal fast-twitch muscle. In contrast, the contractile properties of the fast EDL were relatively unaltered by the hormone administration. Thyrotoxicosis also changed the SOL response to contractile activity as twitch tension, + dP/dt, and - dP/dt remained high, and a faster decline in muscle glycogen and an increase in lactate occurred compared to control muscles. These results clearly demonstrate a preferential effect of thyroid hormone on slow compared to fast skeletal muscle.

Author List

Fitts RH, Brimmer CJ, Troup JP, Unsworth BR

Author

Robert Fitts PhD Professor in the Biological Sciences department at Marquette University

MESH terms used to index this publication - Major topics in bold

Adenosine Triphosphate
Animals
Electric Stimulation
Female
Glycogen
Hyperthyroidism
Isometric Contraction
Isotonic Contraction
Kinetics
Lactates
Lactic Acid
Muscle Contraction
Muscles
Phosphocreatine
Rats
Rats, Inbred Strains
Thyroxine
Triiodothyronine