[Comparative studies on lactate dehydrogenase in serum and plasma of rats (author's transl)]

Values of serum and plasma LDH in rats were comparatively studied, and the following results were obtained: 1) The activity of LDH increased in serum with time during clotting, but no changes of LDH activity were found in plasma. 2) When platelet rich plasma (PRP) was recalcified and allowed to clot, LDH-release from platelets with a corresponding increase of serum LDH was observed, but addition of ADP or thrombin to PRP did not have an effect on LDH-release. 3) LDH-release from platelets by calcium was not inhibited by aspirin, and it was influenced by the quality of the test tube. 4) Values of serum and plasma LDH on experimentally induced liver-damaged or kidney-damaged rats and tumor-bearing rats were examined in relation to their tissue damages, revealing that plasma LDH activity represents the condition of a disease better than serum LDH activity.