{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T20:50:39Z","timestamp":1790196639248,"version":"4.1.0"},"reference-count":0,"publisher":"American Physiological Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1980,1,1]]},"abstract":"<jats:p> The effects of thyrotoxicosis on the contractile properties of soleus muscle were examined in rats given 3 mg of T4 and 1 mg of T3 per kg of diet for 6\u20138 wk. Thyrotoxicosis induced significant decreases in isometric twitch contraction time (CT), one-half relaxation time, and peak twitch tension. The Ca<jats:sup>2+<\/jats:sup> uptake activity of the sarcoplasmic reticulum (SR) was increased in the thyrotoxic muscles; this adaptation in the SR provides a possible mechanism for the alterations in isometric contractile properties. Thyrotoxicosis induced a large increase in fibers classified as type 2, on the basis of an alkali-stable histochemical reaction for ATPase, in the soleus. Although this reaction is commonly interpreted as indicating that a muscle is fast, maximum shortening velocity (V<jats:sub>max<\/jats:sub>) and Mg<jats:sup>2+<\/jats:sup> activated actomyosin ATPase activity were unaffected in the thyrotoxic soleus. Our findings provide evidence that CT and V<jats:sub>max<\/jats:sub> can vary independently and that the histochemical ATPase reaction may not always reflect the biochemical properties that make myosin fast or slow. <\/jats:p><jats:p> actomyosin ATPase; histochemical ATPase reaction; isometric contraction time; maximum shortening velocity; one-half relaxation time; sarcoplasmic reticulum; skeletal muscle <\/jats:p><jats:p> Submitted on April 13, 1979 <\/jats:p><jats:p> Accepted on August 7, 1979 <\/jats:p>","DOI":"10.1152\/ajpcell.1980.238.1.c15","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T10:17:50Z","timestamp":1514110670000},"page":"C15-C20","source":"Crossref","is-referenced-by-count":91,"title":["Contractile, biochemical, and histochemical properties of thyrotoxic rat soleus muscle"],"prefix":"10.1152","volume":"238","author":[{"given":"R. H.","family":"Fitts","sequence":"first","affiliation":[{"name":"Department of Biology, Marquette University, Milwaukee, Wisconsin 53233; and Departments of Preventive Medicine and Neurology, Washington University School of Medicine, St. Louis, Missouri 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W. W.","family":"Winder","sequence":"additional","affiliation":[{"name":"Department of Biology, Marquette University, Milwaukee, Wisconsin 53233; and Departments of Preventive Medicine and Neurology, Washington University School of Medicine, St. Louis, Missouri 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. H.","family":"Brooke","sequence":"additional","affiliation":[{"name":"Department of Biology, Marquette University, Milwaukee, Wisconsin 53233; and Departments of Preventive Medicine and Neurology, Washington University School of Medicine, St. Louis, Missouri 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K. K.","family":"Kaiser","sequence":"additional","affiliation":[{"name":"Department of Biology, Marquette University, Milwaukee, Wisconsin 53233; and Departments of Preventive Medicine and Neurology, Washington University School of Medicine, St. Louis, Missouri 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. O.","family":"Holloszy","sequence":"additional","affiliation":[{"name":"Department of Biology, Marquette University, Milwaukee, Wisconsin 53233; and Departments of Preventive Medicine and Neurology, Washington University School of Medicine, St. Louis, Missouri 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.1980.238.1.C15","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:56:31Z","timestamp":1718654191000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1980.238.1.C15"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,1,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1980,1,1]]}},"alternative-id":["10.1152\/ajpcell.1980.238.1.C15"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1980.238.1.c15","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1980,1,1]]}}}