Insulin-like activity of bradykinin on amino acid balances across the human forearm.

In order to investigate whether bradykinin which has been shown to improve carbohydrate metabolism of skeletal muscle exhibits also insulin-like activity on amino acid metabolism, balances of oxygen and 13 amino acids across the forearm and forearm blood flow were determined in normal subjects during the arterial infusion of insulin (n = 9, 250 mu-units x kg-1 x min-1), bradykinin (n = 7, 0.2 ng x kg-1 x min-1) and papverine (n = 5, 2 microgram x kg-1 x min-1). As expected, the infusion of insulin exhibited significant reduction of the release of glycine, proline, valine, phenylalanine, leucine, threonine and isoleucine. As insulin, bradykinin lessened the release of 9 amino acids: Glycine, serine, ornithin, valine, leucine, isoleucine and tyrosine. On the contrary, papaverine which exhibited almost identical accelerationof forearm blood flow as bradykinin, did not influence the amino acid release from forearm muscle. These findings further support the notion that kinins liberated during muscle work might be involved in the work-induced insulin-like action on carbohydrate- and also on amino acid metabolism.