Growth hormone ribosomal activity

Presumably the increase in RNA polymerase activity produced by growth hormone then leads to the enhanced synthesis of muscle RNA. Recent Experiments by Earl and Komer (17) using heart muscle have shown that 12 hours after the administration of growth hormone there is an increase in the in vivo incorporation of P-labeled inorganic phosphate into ribosomal and transfer RNA. The activation of the polymerase enzyme is also reflected in the fact that the total number of ribosomes in muscle appears to increase after the enzyme has become fully activated (12). 

By itself, an increase in the number of ribosomes in a skeletal muscle cell might increase its protein synthetic capability. However, growth hormone also appears to increase the activity of the ribosomes to catalyse the incorporation of amino acids into protein. Using equal amounts of ribosomes isolated from leg muscles of rats treated for various periods of time with PGH, Florini and Breuer (12) measured the ability of these particles to incorporate %-leucine from leucyl-s-RNA into RNA in an in vitro system in which co-factors and additives were... 

RP chromatography has been used to separate a wide range of proteins of many types, but much of the published work has been concerned with a few restricted classes growth factors, peptide hormones and immunomodulators, virus proteins, haemoglobins and ribosomal proteins account for half of published separations. It is no coincidence that, in most of these cases, the proteins were either structurally robust or the retention of biological activity was of secondary importance. 

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