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The impact of feeding β 2 ‐adrenergic agonists on rainbow trout muscle β 2 ‐adrenoceptors and protein synthesis
Author(s) -
Lortie M. B.,
Arnason T.,
Dugan S. G.,
Nickerson J. G.,
Moon T. W.
Publication year - 2004
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.0022-1112.2004.00482.x
Subject(s) - rainbow trout , biology , medicine , endocrinology , ractopamine , myofibril , trout , zoology , fish <actinopterygii> , fishery
The β 2 ‐adrenergic agonists (β 2 ‐AAs) clenbuterol (CLEN) and ractopamine (RACT) were fed to rainbow trout Oncorhynchus mykiss for 30–37 days and red and white muscle β 2 ‐adrenoceptor (β 2 ‐AR) binding characteristics and mRNA expression were assessed in parallel with fractional protein synthetic rates. Feeding CLEN or RACT had no significant effect on any body or physiological variables measured. There were no significant differences in the number of binding sites (B max ) while a significant increase in the K d was observed for the β‐ARs of red and white muscle membranes isolated from β 2 ‐AA‐fed rainbow trout. No change in β 2 ‐AR mRNA levels was observed with β 2 ‐AA feeding, implying that these β 2 ‐AAs do not act at the transcriptional level at least for the β 2 ‐AR. The β 2 ‐AA treatments, however, did significantly increase red and white muscle fractional protein synthesis rates in whole protein, myofibrillar protein and sarcoplasmic soluble protein fractions. Although not conclusive, this study supports a direct link between rainbow trout muscle β 2 ‐ARs and muscle protein synthesis.