[Comparative biochemical and histological studies of the effect of magnesium and profound hypothermia on the preservation of the isolated perfused rat liver (author's transl)]. / Etude comparative biochimique et histologique de l'action du magnésium et de l'hypothermie profonde sur la conservation du foie de rat isolé.

In order to determine, if magnesium aspartate has the same favorable effect on the liver as on the arrested heart, the isolated rat liver preperfused with isotonique Mg-aspartate or saline solution 15 minutes and stored 1 hour at 36 degrees C or 12 hours at 36 degrees C has been reperfused 150 minutes at 37 degrees C. During the storage the concentrations of ATP and ADP decrease significantly whereas AMP, lactate and beta-hydroxybutyrate increase remarkably, accompanied by a pronounced breakdown of glycogen. Upon reperfusion a de novo synthesis of ATP and ADP is resumed. Lactate, beta-hydroxybutyrate and AMP approach normal values whereas a resynthesis of glycogen is missing. A focal distribution of well preserved and disintegrated hepatocytes is being observed and seems rather to be due microcirculatory disorders. No conclusive evidence of a protective Mg-effect as observed in induced cardiac arrest has been obtained. Several concentrations of Mg-aspartate should be studied, in order to elucidate the different acting mechanism of Mg++ on the two organs.

The effect of magnesiumaspartate on preservation of the rat liver.

1. Isolated rat livers reperfused with an oxygenated isotonic Mg-aspartate or saline solution and stored 1 h at 36 degrees C, 4 h at 22 degrees C or 12 h at 6 degrees C were reperfused at 37 degrees C 150 min with a Krebs-Henseleit solution containing bovine albumin and erthrocytes gased with a 95% O2-5% CO2 gas mixture. 2. Light- and electronmicroscopic studies revealed minor changes after storage, whereas in the reperfused livers a focal distribution of well preserved and disintegrated hepatocytes was observed. 3. During storage the sum of adenine nucleotides in general decreased markedly paralleled by a significant rise of the lactate/pyruvate and hydroxybutyrate/acetoacetate ratios and pronounced breakdown of glycogen. Oxidative phosphorylation was resumed upon reperfusion resulting in de novo synthesis of ATP and ADP. The lactatelpyruvate and hydroxybutyrate/acetoacetate ratios normalized, whereas a resynthesis of glycogen was missing. 4. No conclusive evidence of a protective Mg-effect as observed in induced cardiac arrest has been obtained, probably due to structural and metabolic differences between the two organs and microcirculatory disorders as has been demonstrated by measurements of oxygen uptake using the multiwire electrode.