Potentiation by m-cresol on transepithelial sodium transport across frog skin induced by insulin

1. In this study we found that insulin mixed with m-cresol, normally used as pharmaceutical preparation, shows an earlier and larger stimulating effect on transepithelial sodium transport than insulin alone. 2. The action displayed by the m-cresol seems to be specific for insulin because m-cresol mixed with ADH, a hormone known to stimulate sodium transport, failed to show the potentiation seen for insulin. 3. It is proposed that m-cresol could facilitate the interaction with its receptor by modifying the insulin molecule. 4. This finding could be of biological and pharmacological importance.