Metabolic effects of prostaglandin E1 on human skeletal muscle with special regard to the amino acid metabolism.

The influence of intra-arterial (i.a.) prostaglandin E1 (PGE1) on the metabolism of amino acids, glucose and free fatty acids in healthy volunteers was determined by means of the forearm technique. The continuous increase of perfusion from baseline 2.9 +/- 0.1 ml/100 g x min to 5.4 +/- 1.5 after 60 minutes of PGE1 infusion, indicates an increase of basal glucose utilisation from 0.51 +/- 0.11 to 2.5 +/- 0.36 mumol/100 g x min via and additional raised glucose extraction rate. Furthermore, PGE1 resulted in a cessation of the basal muscular glycerol production and led to a change from a basal production of free fatty acids to a net absorption into the muscle. This change from an oxidation of free fatty acids to glucose results in an improved energetic gain of 0.72 mol ATP/mol 02. Baseline values showed a release of most amino acids which, after PGE1 decreased significantly or even changed to an intake. The overall balance of all amino acids changed from baseline -27.9 (i.e. release) to +33.2 nmol/100 x min (i.e. intake). This indicates an inhibition of muscular proteolyses and/or a stimulation of protein synthesis under i.a. PGE1. This additional metabolic effect of PGE1 might be an explanation as to why agents with purely vasodilating actions did not prove therapeutically effective in the treatment of peripheral arterial disease in the past.