Aldosterone stimulates Na+ transport without affecting citrate synthase activity in cultured cells

Aldosterone increases citrate synthase activity in toad urinary bladder and mammalian kidney. It has been suggested that this action is important to aldosterone stimulation of Na+ transport, and it has been used as a marker of those epithelia which are stimulated by aldosterone. We describe three continuous lines of cultured cells derived from toad urinary bladder and toad kidney in which aldosterone increases active Na+ transport but does not increase the activity of citrate synthase. Therefore, in cultured cells at least, citrate synthase is not a critical enzyme for, or a suitable marker of, aldosterone stimulation of Na+ transport.