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Evidence for a direct action of thyroid hormone in specifying muscle properties.
Am J Physiol 1982; 242(3):R401-8AJ

Abstract

Thyroidal trophic effects on slow-twitch skeletal muscle properties were compared in normally innervated and denervated soleus of rats maintained at different thyroid states. Hypothyroidism caused fast to slow changes in fiber type composition (99% decrease in proportion of type II fibers), ATPase activities (down 20-30%), myosin light chain pattern (54% less fast light chains), calcium uptake by SR (down 60%), LDH activity (down 11%), and isozyme pattern (9% decrease in M-subunits). Changes of similar magnitude but opposite in direction were induced by thyrotoxicosis. Denervations reversed, to varying degrees, the fast to slow transformations observed in hypothyroidism. However the slow to fast changes found in hyperthyroidism were facilitated rather than inhibited by denervation. These latter results clearly show that the hormone effect can be elicited in the absence of motor innervation. Furthermore, denervation alone caused slow to fast changes in euthyroid muscles. From these results, it is proposed that denervation and dysthyreosis alter muscle properties by independent mechanisms. Our data favor a direct action of thyroid hormone over a neurally mediated mechanism.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo 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

6461259

Citation

Nwoye, L, et al. "Evidence for a Direct Action of Thyroid Hormone in Specifying Muscle Properties." The American Journal of Physiology, vol. 242, no. 3, 1982, pp. R401-8.
Nwoye L, Mommaerts WF, Simpson DR, et al. Evidence for a direct action of thyroid hormone in specifying muscle properties. Am J Physiol. 1982;242(3):R401-8.
Nwoye, L., Mommaerts, W. F., Simpson, D. R., Seraydarian, K., & Marusich, M. (1982). Evidence for a direct action of thyroid hormone in specifying muscle properties. The American Journal of Physiology, 242(3), pp. R401-8.
Nwoye L, et al. Evidence for a Direct Action of Thyroid Hormone in Specifying Muscle Properties. Am J Physiol. 1982;242(3):R401-8. PubMed PMID: 6461259.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence for a direct action of thyroid hormone in specifying muscle properties. AU - Nwoye,L, AU - Mommaerts,W F, AU - Simpson,D R, AU - Seraydarian,K, AU - Marusich,M, PY - 1982/3/1/pubmed PY - 1982/3/1/medline PY - 1982/3/1/entrez SP - R401 EP - 8 JF - The American journal of physiology JO - Am. J. Physiol. VL - 242 IS - 3 N2 - Thyroidal trophic effects on slow-twitch skeletal muscle properties were compared in normally innervated and denervated soleus of rats maintained at different thyroid states. Hypothyroidism caused fast to slow changes in fiber type composition (99% decrease in proportion of type II fibers), ATPase activities (down 20-30%), myosin light chain pattern (54% less fast light chains), calcium uptake by SR (down 60%), LDH activity (down 11%), and isozyme pattern (9% decrease in M-subunits). Changes of similar magnitude but opposite in direction were induced by thyrotoxicosis. Denervations reversed, to varying degrees, the fast to slow transformations observed in hypothyroidism. However the slow to fast changes found in hyperthyroidism were facilitated rather than inhibited by denervation. These latter results clearly show that the hormone effect can be elicited in the absence of motor innervation. Furthermore, denervation alone caused slow to fast changes in euthyroid muscles. From these results, it is proposed that denervation and dysthyreosis alter muscle properties by independent mechanisms. Our data favor a direct action of thyroid hormone over a neurally mediated mechanism. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/6461259/Evidence_for_a_direct_action_of_thyroid_hormone_in_specifying_muscle_properties L2 - http://www.physiology.org/doi/full/10.1152/ajpregu.1982.242.3.R401?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -