Growth hormone radioimmunoassay (RIA)

Growth hormone not only stimulates growth, but also influences several other metabolic processes in the body. By its growth-promoting activity, the hormone accelerates the synthesis of nucleic acids and proteins by stimulating the uptake of amino acids by the tissues. Using rat diaphragm preparations in vitro, a reduced uptake of several amino acids following Hypophysectomy has been demonstrated. Among other hormones, only pancreatic insulin is a potent stimulator of this process. On the cellular level, growth hormone effects appear to be mediated by cAMP. The hormone affects protein synthesis in rat levator ani and cardiac muscles, but they display a different behavior from the diaphragm. In adipose tissue, growth hormone also has a stimulatory effect on protein synthesis in virto, primarily at the ribosomal level as RNA synthesis is blocked by actinomycin D. Growth hormone effects on protein synthesis in liver were similarly demonstrated and require a lower concentration of hormone than for synthesis by muscle or adipose tissue