Complex sentence: In any case, interaction with both the MR and AR have been observed for metabolites of spironolactone, whereas spironolactone itself has only very low affinity for the ER suggesting that its metabolites are responsible for this activity.
Split into simpler sentences: In any case, interaction with both the MR and AR have been observed for metabolites of spironolactone. On the other hand, spironolactone itself has only very low affinity for the ER, suggesting that its metabolites may be responsible for this activity.