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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1996-6-13
pubmed:abstractText
We examined the role of IGF-I in muscle growth stimulated by a beta-adrenergic agonist, clenbuterol. Ewe lambs (90 d old, 20.4 kg mean live weight) were allotted to five groups. A pretreatment control group of five lambs was slaughtered immediately (0 d). The other four groups of six ewes ate freely for 38 or 80 d and were then slaughtered. Half those lambs received clenbuterol (400 micrograms.kg live weight-1.d-1) as a dietary supplement. Blood was collected at intervals from 19 d before supplementation began (0 d) until slaughter. Prerigor muscle samples were sectioned for detection of IGF-I receptors and myofibrillar ATPase activity. Carcass weights were slightly increased by treatment, whereas muscle weights (semimembranosus, gastrocnemius, and biceps femoris) were greatly increased (P < .001), up to 48% at 80 d for semimembranosus. Clenbuterol significantly decreased collagen concentration because myofibrillar proteins were preferentially produced. Collagen solubility was unaffected. Total RNA:total DNA in semimembranosus and gastrocnemius showed transcription was still stimulated between 38 and 80 d. Fiber type area analysis indicated a shift toward glycolytic metabolism, confirmed by iron measurements. However, clenbuterol did not change the portion of muscle occupied by each ATPase class, and the data indicated that type I fibers, though smaller, became relatively more numerous. In spite of significant muscle changes, plasma IGF-I was unaffected by clenbuterol. Similarly, there was no difference in the specific binding of [125I]IGF-I at slaughter between treated and control lambs. However, a response in the first few days of treatment, preceding visible hypertrophy, cannot be excluded.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-8812
pubmed:author
pubmed:issnType
Print
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3069-77
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
The role of insulin-like growth factor I in clenbuterol-stimulated growth in growing lambs.
pubmed:affiliation
Meat Industry Research Institute of New Zealand (Inc.), Hamilton, New Zealand.
pubmed:publicationType
Journal Article