O. Halevy et al., Early-age heat exposure affects skeletal muscle satellite cell proliferation and differentiation in chicks, AM J P-REG, 281(1), 2001, pp. R302-R309
Citations number
58
Categorie Soggetti
Physiology
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Exposure of young chicks to thermal conditioning (TC; i.e., 37 degreesC for
24 h) resulted in significantly improved body and muscle growth at a later
age. We hypothesized that TC causes an increase in satellite cell prolifer
ation, necessary for further muscle hypertrophy. An immediate increase was
observed in satellite cell DNA synthesis in culture and in vivo in response
to TC of 3-day-old chicks to levels that were significantly higher than th
ose of control chicks. This was accompanied by a marked induction of insuli
n-like growth factor-I (IFG-I), but not hepatocyte growth factor in the bre
ast muscle. No significant difference between treatments in plasma IGF-I le
vels was observed. A marked elevation in muscle regulatory factors on day 5
, followed by a decline in cell proliferation on day 6 together with contin
uous high levels of IGF-I in the TC chick muscle may indicate accelerated c
ell differentiation. These data suggest a central role for IGF-I in the imm
ediate stimulation of satellite cell myogenic processes in response to heat
exposure.