Excretion of d-malic acid in the chicken

¹ Department of Physiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio

The excretion of the physiologically inert d-malic acid has been studied in the chicken. It is actively secreted by the renal tubule. There is no mutual interference between the capacity to secrete d-malic and PAH. Benemid does not inhibit d-malic secretion. N'-methylnicotinamide, cyanine no. 863 and Priscoline likewise have no effect on d-malic secretion. During secretion by the tubules d-malic acid retains its optical configuration. It is concluded that the renal tubular secretion of d-malic acid occurs by a mechanism different from the one for other organic acids or organic bases reported thus far.