Previous studies showed that beta2-adrenergic agonists (beta 2-AAs) enhanced muscle growth and reduced lipid deposition in animals of agricultural and economical importance, including teleost fish. The goal of the present study was to provide a mechanistic explanation underlying the reported beta2-AA-induced muscle growth in the rainbow trout (Oncorhynchus mykiss). Using radioligand binding assays and adenylyl cyclase/cAMP assays, this study characterized and demonstrated the presence of functional beta2-adrenoceptors (beta2-ARs) on red and white muscle membranes. Trout fed 40 ppm of two beta2-AAs (clenbuterol and ractopamine) for 30 days showed no significant changes in measured body and physiological parameters, beta2-AR numbers or beta2-AR mRNA levels in red or white muscle. However, treatments significantly increased fractional protein synthesis rates in red and white muscle. These studies demonstrate that beta2-AAs impact muscle protein synthesis by mechanisms initiated at the muscle membrane beta 2-AR and include the beta2-AR-signalling pathway in a teleost fish.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/6268 |
| Date | January 2002 |
| Creators | Lortie, Michel B. |
| Contributors | Moon, Thomas W., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 119 p. |
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