TY - JOUR
T1 - Alterations in rat cardiac myosin isozymes induced by whole-body irradiation are prevented by 3,5,3′-l-triiodothyronine
AU - Litten, Raye Z.
AU - Fein, Henry G.
AU - Gainey, Grealon T.
AU - Walden, Thomas L.
AU - Smallridge, Robert C.
N1 - Funding Information:
From the Departments of Physiology and Biochemistry, Armed Forces Radiobiology Research Institute, Bethesda, MD. and the Division of Medicine. Walter Reed Army Institute of Research, Washington, DC. Supported by the Armed Forces Radiobiology Research Institute, Defense Nuclear Agency, Department of the Army, and Department of Defense, under Research Work Unit 0169. The views presented in this paper are those of the authors. No endorsement by the Defense Nuclear Agency and the Department of Defense has been given or should be inferred. Research was conducted according to the principles enunciated in the ‘<Guidefor the Care and Use of Laboratory Animals,“prepared by the Institute of Laboratory Animal Resources, National Research Council. Address reprint requests to R.Z. Litten. PhD, Room 16C-05, Division of Clinical and Prevention Research, National Institute on Alcohol Abuse and Alcoholism. Parklawn Bldg. Rockville, MD 20857. This is a US government work. There are no restrictions on its use. 0026-0495/90/3901-0010$0.00/0
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1990/1
Y1 - 1990/1
N2 - Changes in cardiac myosin isozymes and serum thyroid hormone levels were investigated in rats following 10 Gy whole-body gamma irradiation. The percent β-myosin heavy chain increased from 21.3 ± 1.8 to 28.1 ± 6.8 (NS) at 3-day postirradiation, 37.7 ± 1.9 (P<.001) at 6-day postirradiation, and 43.8 ± 3.3 (P<.001) at 9-day postirradiation. Along with the change in myosin isozymes was a significant 53% decrease (P<.001) in the serum thyroxine (T4) level by day 3 postirradiation, remaining depressed through day 9 postirradiation. The serum 3,5,3′-triiodothyronine (T3) level, however, was normal until day 9, when significant depression was also observed. In contrast, the thyroid-stimulating hormone (TSH) level was significantly increased by fourfold at day 3, returning to near normal values by day 9 postirradiation. Daily injections of physiological doses of T3 ( 0.3 μg 100 g body weight) prevented the change in the myosin isozymes following whole-body irradiation. Daily pharmacological injections of T3 ( 3.0 μg 100 g body weight) to the irradiated rats produced a further decrease in the percent β-myosin heavy chain (below control values) indicating tissue hyperthyroidism. Thus, this study suggests that the change in myosin isozymes following whole-body irradiation is caused by an alteration in thyroid hormone activity.
AB - Changes in cardiac myosin isozymes and serum thyroid hormone levels were investigated in rats following 10 Gy whole-body gamma irradiation. The percent β-myosin heavy chain increased from 21.3 ± 1.8 to 28.1 ± 6.8 (NS) at 3-day postirradiation, 37.7 ± 1.9 (P<.001) at 6-day postirradiation, and 43.8 ± 3.3 (P<.001) at 9-day postirradiation. Along with the change in myosin isozymes was a significant 53% decrease (P<.001) in the serum thyroxine (T4) level by day 3 postirradiation, remaining depressed through day 9 postirradiation. The serum 3,5,3′-triiodothyronine (T3) level, however, was normal until day 9, when significant depression was also observed. In contrast, the thyroid-stimulating hormone (TSH) level was significantly increased by fourfold at day 3, returning to near normal values by day 9 postirradiation. Daily injections of physiological doses of T3 ( 0.3 μg 100 g body weight) prevented the change in the myosin isozymes following whole-body irradiation. Daily pharmacological injections of T3 ( 3.0 μg 100 g body weight) to the irradiated rats produced a further decrease in the percent β-myosin heavy chain (below control values) indicating tissue hyperthyroidism. Thus, this study suggests that the change in myosin isozymes following whole-body irradiation is caused by an alteration in thyroid hormone activity.
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U2 - 10.1016/0026-0495(90)90149-7
DO - 10.1016/0026-0495(90)90149-7
M3 - Article
C2 - 2136761
AN - SCOPUS:0025190379
SN - 0026-0495
VL - 39
SP - 64
EP - 68
JO - Metabolism
JF - Metabolism
IS - 1
ER -