Relationship of multiple forms of lactate dehydrogenase to cholestasis.

Lactate dehydrogenase (LDH, E.C. 1.1.1.27) activity was studied in an experimental model (the liver bile of cholecystectomized patients and of rats) by electrophoretic separation on agar gel. The prevalence of the liver LDH5 isoenzyme in bile obtained in this manner is the proof that this fraction is secreted by the liver. The experimental conclusions are supported by the author's own clinical observations of prevalence of the cathodic isocomponents LDH4 and LDH5 in serum, as an indicator of cholestasis in conditions characterized by bile duct obstruction.