TOTAL ACTIVITY AND ISOENZYMIC PATTERNS OF LACTATE-DEHYDROGENASE (LDH)IN VARIOUS RAT-TISSUES

Lactate-dehydrogenase (LDH) isoenzyme patterns were measured by microd isc gel electrophoresis in various tissues (cardiac muscle, kidneys, a drenals, thyroid, liver) and different parts of the brain ( hypothalam us, hippocampus, Nucleus caudatus, cortex cerebri, cerebellum) of albi no male Wistar rats. Total LHD activity had the highest value in cardi ac muscle and liver, and the smallest value in kidneys. In cardiac mus cle the greatest activity was shown by isoenzyme LDH2 (LDH2>LDH3>LDH1> LDH4>LDH5), while the greatest activity in liver was shown by the elec trophoretically ''slowest'' component, LDH5. In the kidneys isoenzyme LDH2 (LDH2>LDH1>LDH4>LDH3>LDH5) had the greatest activity. In haff of the examined animals a discrete subfraction of LDH4 was found in the k idneys. The adrenals and the thyroid showed great similarity in LDH is oenzyme patterns, with the highest value for the electrophoretically ' 'slow'' components LDH5 and LDH4 (LDH5>LDH4>LDH3>LDH2>LDH1). The brain structures had lower total activity when compared with the other tiss ues and organs. The smallest total LDH activity was shown by the cereb ellum. However, all examined brain structures showed marked similarity in LDH isoenzyme patterns: the highest activity for LDH4 and LDH3 and the smallest activity in LDH1. Our results agree with earlier finding s that different tissues and organs of both animals and humans have ch aracteristic LDH isoenzyme patterns.