A Study on Distribution of Lactic Dehydrogenase Isozyme in the Cortex and the Medulla of the Rabbit Kidney

Lee, Woo Hong

Abstract

1. Using the kidney of the rabbit weighing approximately 1.5kg the LDH isozymes, LDH-l through 5, were analyzed on the acetate strip by electrophoresis and it was found that the LDH-3 was the least active isozyme followed by the LDH-2, -4, -1, and -5 in increasing order of activity both in that cortex and the medulla, showing a specific distribution pattern in the two tissues. 2. The difference in the isozymic distribution pattern between the cortex and the medulla was confirmed by separating the H-and M-LDH by DEAE-cellulose, the ratio of M-/H-LDH being l. 441t the medulla and 3. O3 in the cortex, showing more active anaerobic metabolism in the latter than in the former. 3. The total activity of LDH in the 20% homogenate of the total kidney tissue was 10. 55 units/ml the cortical 2.98 units/ml. and the medullary 7. 37 unite/ml. 4. In the unilaterally nephrectomized rabbit. the cortex of the remaining kidney showed increased activities of both H- and M-LDH, but the medullary H-LDH decreased, resulting in increases of the ratio M-,H-LDH both in the cortex and in the medulla 5. In the unilaterally pedicle-clamped rabbit, LDH of the clamped kidney medulla decreased while that of the cortex increased, and LDH of the unclamped kidney showed elevated activity both in the cortex and in the medulla, yielding an increase in the ratio of M-/H-LDH. 6. The specific difference in distribution pattern of LDH igozymes between the cortex and the medulla of the rabbit kidney and an increase of the ratio of M-/H.LDH resulting from functional compensation following unilateral nephrectomy or pedicle clamping have been briefly discussed.