[An electrochemical evidence that some hormones influence the transmembrane transport of lipoic acid by Escherichio coli K 12 (author's transl)].

The influence of diverse substances on the transmembrane transport of lipoic acid can be followed by a recently developed method based on electrochemical measurements of the oxydo-reduction of lipolic acid. This technique was applied to study some hormonal effects on E. coli. The results show that the active transport of lipoic acid (at low lipoic acid concentration) through the E. coli K 12 membrane is increased by hydrocortisone and insulin, but remains unaffected by adrenalin. At high lipoic acid concentration, its passive diffusion through the E. coli membrane is enhanced by adrenalin, but decreased by insulin and hydrocortisone. These results are similar to those reported for rat liver mitochondria and erythrocites.