Triacylglycerol synthesis in the different skeletal muscle fiber
sections of the rat.
Budohoski, Leszek, Jan Gorski, Krystyna Nazar, Hanna Kaciuba-Uscilko,
and Ronald L. Terjung.
Department of Physiology, State University of New York, Health
Science Center at Syracuse, Syracuse, New York 13210 and Department
of Applied Physiology, Medical Research Center, Polish Academy of
Sciences, Warsaw, Poland
APStracts 3:0114E, 1996.
Triacylglycerol (TG) synthesis rates of low-oxidative fast-twitch
white, high-oxidative fast- and slow-twitch red skeletal muscle fiber
sections of adults rats were measured by the incorporation of
perfusate-derived palmitate (FA) into the neutral lipid fraction,
utilizing a perfused hindquarter preparation under high flow
conditions. The perfusion medium consisted of 95%/5% O2/CO2-Krebs
-Henseleit buffer, pH 7.4 containing 5 g/100 ml BSA, 100 U/ml insulin,
5 mmol/L glucose, amino acids and added FA including 0.1 Ci/ml 3H
-palmitate. FA incorporation was linear with time. TG synthesis rates
correlated (r 0.90) with the oxidative capacity of each of the
different fiber type sections and increased in proportion to
perfusate [FA] (0.25, 0.5, 1.0, 1.5, and 2.0 mmol/L). TG synthesis
rates among different muscle fiber sections were related (r 0.90) to
perfusate flow during high flow conditions; however, this was not
causal, as TG synthesis rates within each muscle fiber section were
independent of flow rate when experimentally varied over 3-fold
range. Thus, the relatively high TG synthesis rates, observed in the
high-oxidative muscle sections, are not uniquely related to their
high flow capacities but inherent to the TG synthesis process,
probably events associated with FA uptake and/or capacity of the TG
synthesis pathway.
Received 7 March 1996; accepted in final form 22 May 1996.
APS Manuscript Number E115-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96