|
|
||||||||
AJP - Endocrinology and Metabolism, Vol 260, Issue 2 E272-E279, Copyright © 1991 by American Physiological Society
ARTICLES |
R. M. McAllister, R. W. Ogilvie and R. L. Terjung
Department of Physiology, State University of New York Health Science Center, Syracuse 13210.
Functional and metabolic responses of hypothyroid skeletal muscle were evaluated during steady-state isometric contraction conditions, using an isolated perfused rat hindlimb preparation. Treating rats with propylthiouracil (PTU) for 4-5 mo resulted in a 55% decrease (P less than 0.001) in citrate synthase activity in plantaris muscle and phenotypic remodeling of the plantaris, evident by a threefold increase in type I fiber area and a 13% decrease in type II fiber area. Perfusion of PTU (n = 9) and control (n = 9) rat hindlimbs of similar size, with similar inflow (approximately 10 ml/min) and oxygen content (approximately 20 g/100 ml), resulted in similar oxygen deliveries to the contracting muscles (PTU 11.4 +/- 0.58, control 9.54 +/- 0.75 mumol.min-1.g-1; P greater than 0.05). Ten-minute tetanic contraction (100 ms at 100 Hz) periods at 4, 8, 15, 30, and 45 tetani/min were elicited in consecutive ascending order. Oxygen consumption (VO2) was lower in the PTU group at all contraction frequencies (P less than 0.005), with a decrease in peak VO2 of 44% (PTU 3.01 +/- 0.29, control 5.35 +/- 0.42 mumol.min-1.g-1; P less than 0.001). Oxygen extraction by the PTU muscle was only approximately 25% of that delivered. Developed tension was initially less (15%; P less than 0.05) in the PTU group but declined in a similar manner, as a percent of initial, to that of the control group. The slightly lower absolute tension development of the PTU muscle could not account for the large reduction in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
![]() |
S. He, D. A. Shelly, A. E. Moseley, P. F. James, J. H. James, R. J. Paul, and J. B. Lingrel The {alpha}1- and {alpha}2-isoforms of Na-K-ATPase play different roles in skeletal muscle contractility Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2001; 281(3): R917 - R925. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Lee, J. K. Shoemaker, P. M. McQuillan, A. R. Kunselman, M. B. Smith, Q. X. Yang, H. Smith, K. Gray, and L. I. Sinoway Effects of forearm bier block with bretylium on the hemodynamic and metabolic responses to handgrip Am J Physiol Heart Circ Physiol, August 1, 2000; 279(2): H586 - H593. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |