RESUMO
This paper reports on an experiment concerning the involvement of catecholamines in the biosynthesis of nucleic acids and proteins at muscular levels, using various types of skeletal muscles (psoas, diaphragm, soleus) and heart muscles from male Wistar rats treated with adrenalin. Assessment of the biosynthetic processes was made by the uptake level of 3H thymidine, 3H uridine, and 3H triptophan in the muscles. The experiment showed the followings: a) nucleic acids and protein synthesis stayed unchanged in the psoas; b) adrenalin stimulated the uptake of the radioactive precursors in the diaphragm and soleus, and c) the biosynthetic processes were inhibited in the myocardium by adrenalin administration. Though adrenalin is known to stimulate proteic synthesis in the skeletal muscle, our study showed that this process occurs only in certain types of muscles (with slow contraction). Inhibition of proteic synthesis in the myocardium in the presence of adrenalin might be one of the cellular mechanisms involved in cardiac failure.
