Effect of thyrotoxicosis on sarcoplasmic reticulum in rat skeletal muscle. Am J Physiol 1982 Sep;243(3):C151-5
Date
09/01/1982Pubmed ID
7114246DOI
10.1152/ajpcell.1982.243.3.C151Scopus ID
2-s2.0-0019982551 (requires institutional sign-in at Scopus site) 32 CitationsAbstract
The effect of thyrotoxicosis on the capacity of fragmented sarcoplasmic reticulum (FSR) and crude homogenate (CH) to sequester Ca2+ was determined in rat muscle for the slow-twitch type I soleus (SOL), the fast-twitch type IIA deep region of the vastus lateralis (DVL),and the fast-twitch type IIB superficial region of the vastus lateralis (SVL). The maximal rate of Ca2+ uptake (Vmax) and Km were determined in both the CH and FSR preparations, and the total Ca2+ uptake capacity of the CH was determined. In the slow SOL, thyrotoxicosis increased the Vmax (8.20 +/- 0.96 vs. 15.70 +/- 0.92 mumol Ca2+ . g wet muscle-1 . min-1) and the total Ca2+ uptake (17.62 +/- 1.30 vs. 27.13 +/- 2.16 mumol Ca2+ . g wet muscle-1) of the CH preparation. Thyrotoxicosis increased the FSR yield 2.3-fold in the slow-twitch SOL; however, the kinetic characteristics (Vmax and Km) of these vesicles were not altered. Thyrotoxicosis had no effect on the CH and FSR preparations in either the type IIA or type IIB sample. These results can be explained by a thyroid hormone-mediated increase in the quantity of the sarcoplasmic reticulum in type I muscle and suggest no effect on the hormone on the qualitative nature of the Ca2+-enzyme interaction.
Author List
Kim DH, Witzmann FA, Fitts RHAuthor
Robert Fitts PhD Professor in the Biological Sciences department at Marquette UniversityMESH terms used to index this publication - Major topics in bold
AnimalsCalcium
Female
Hyperthyroidism
Kinetics
Organ Size
Rats
Rats, Inbred Strains
Sarcoplasmic Reticulum