Clenbuterol increases the expression of myogenin but not myod in
immobilised rat muscles.
Delday, M I, and C A Maltin.
The Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB
APStracts 4:0042E, 1997.
Immobilisation of one hindlimb of young rats in plantar flexion for 3
days led to changes in the plantaris muscles. These comprised a loss
of muscle mass, and a reduction in protein and RNA content, but no
change in the transcript levels of the myogenic regulatory factors,
myogenin and myoD. Dietary administration of the [beta]-adrenoceptor
agonist, clenbuterol (2mg/kg diet), which has been shown to
ameliorate muscle wasting in a wide range of atrophic conditions,
also limited muscle wasting in terms of weight, protein and RNA in
the immobilised plantaris muscles. In addition, drug treatment in
immobilised plantaris muscles was associated with a marked increase
in the steady state levels of mRNA for myogenin (approximately 360%
increase over control), but not myoD. These data provide the first
evidence for independent changes in these two myogenic regulatory
factors in immobilised muscle and suggest that the action of
clenbuterol on these factors may depend on the mechanistic basis for
the atrophic response.
Received 25 July 1996; accepted in final form 16 January 1997.
APS Manuscript Number E451-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 20 February 1997