Effect of tri-iodothyronine administration on skeletal muscle intracellular pH in the rat.
1. Male Wistar rats were injected with tri-iodothyronine intraperitoneally for either 3 or 5 days. 2. Using 31P nuclear magnetic resonance spectroscopy, skeletal muscle intracellular bioenergetics of the leg were studied at rest and during sciatic nerve stimulation. 3. Tri-iodothyronine caused intracellular alkalinization of the cell, implying that administration of tri-iodothyronine induces an alteration in the set point for the sodium/proton antiport, the chief controller of intracellular pH. 4. During stimulation, there was less acidification of the skeletal muscle cell in the tri-iodothyronine-injected rats, implying either increased intrinsic buffering capacity of the muscle or increased proton efflux possibly due to increased activity of the sodium/proton antiport. 5. Effective proton efflux from the skeletal muscle cell may be sensitive to circulating levels of tri-iodothyronine.
Thompson
C H
CH
MRC Biochemical and Clinical Magnetic Resonance Unit, John Radcliffe Hospital, Headington, Oxford, U.K.
Anderson
Y
Y
Jagasia
D H
DH
Radda
G K
GK
Rajagopalan
B
B
D000818:Animals; D004558:Electric Stimulation; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D005082:Physical Exertion / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000502:physiology; D014284:Triiodothyronine / Q000494:pharmacology* / Q000502:physiology
D007773:Lactates; D010725:Phosphocreatine; D014284:Triiodothyronine; D019344:Lactic Acid