Neural regulation of the enhanced uptake of glucosein skeletal
muscle after endotoxin.
Lang, Charles H.
Department of Surgery, State University of New York, Stony Brook,
New York 11794-8191
APStracts 2:0090R, 1995.
Previous studies have demonstrated that in vivo injection of LPS
acutely stimulates glucose uptake (GU) in skeletal muscle. The
purpose of the present study was to determine whether this enhanced
GU is neurally mediated. In the first group of rats, a unilateral
sciatic nerve transection was performed 3 h prior to injection of LPS
and in vivo GU assessed using [14C]-2-deoxyglucose 40 min after LPS
injection. At this time, LPS-treated rats were hyperglycemic (12 mM)
and insulin levels were not different from control rats. In the
innervated leg, LPS increased GU 43-228% depending on the muscle
type. In contrast, LPS failed to increase GU in muscles from the
denervated limb. In other experiments, somatostatin was infused to
produce an insulinopenic condition prior the injection of LPS.
Despite insulinopenia, muscle GU was still increased by LPS. In
control rats, using the euglycemic hyperinsulinemic clamp technique,
acute muscle denervation was shown to impair insulin-mediated GU in
the presence of pharmacological, but not physiological, insulin
levels. Noninsulin-mediated glucose uptake (NIMGU) was assessed in
rats that were insulinopenic and hyperglycemic. In innervated muscle,
NIMGU was increased 56-126% and 118-145% when the plasma glucose was
elevated to 9 mM and 12 mM, respectively. In contrast, hyperglycemia
-induced increases in NIMGU were attenuated in denervated muscle.
These data demonstrate that (1) the early LPS-induced stimulation of
muscle glucose uptake is mediated via a noninsulin-mediated pathway
and that (2) the LPS-induced increase in NIMGU in muscle is neurally
mediated.
Received 23 September 1994; accepted in final form 23 March 1995.
APS Manuscript Number R551-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 April 1995.