Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2003
Publication Date: 5/1/2003
Citation: Davis, T.A., Bush, J.A., Vann, R.C., Suryawan, A., Burrin, D.G. 2003. Somatotropin regulation of skeletal muscle protein deposition in pigs [Abstract]. Journal of Dairy Science. 81(Suppl 1.):65. Interpretive Summary:
Technical Abstract: A primary goal of exogenous somatotropin (ST) treatment is to increase lean body mass. This is accomplished, in part, by increasing the efficiency with which dietary amino acids are used for protein deposition. ST administration also improves protein balance by minimizing the loss of protein during fasting and maximizing the protein gained during meal absorption. Amino acid catabolism is reduced by ST treatment as indicated by reductions in blood urea nitrogen concentrations, urea synthesis, liver urea cycle enzyme activity, and amino acid oxidation. Stable isotope tracer/mass transorgan balance studies have recently demonstrated that ST treatment increases protein anabolism in young, growing swine by increasing protein synthesis in the hindlimb and portal-drained viscera in the fully-fed state, with no effect of ST on protein degradation. More detailed study to examine the tissue-specific response to ST treatment indicates that GH treatment increases protein synthesis in skeletal muscle by increasing the efficiency of the translational process, but only in the fed state. The ST-induced stimulation of skeletal muscle protein synthesis in the postprandial state involves mechanisms that enhance the binding of both mRNA and initiator methionyl-tRNA to the 40S ribosomal subunit. ST increases protein synthesis in the intestine and liver in both the fasted and fed state by increasing ribosome number, with no change in translation initiation. Thus, the protein synthetic response to ST treatment is tissue specific and dependent upon nutritional state.