Determination Of Isoenzymes Research Articles

Lactate Dehydrogenase in Human Seminal Plasma

Lactate dehydrogenase (LDH) activity and the various isoenzymes have been quantitatively determined in seminal fluid from healthy men and from patients with various pathological conditions in their accessory genital glands. The total activity is about 1500 m-I.U./ml (range 380–4540). There was no significant difference in total activity between the various groups of patients. Successive samples from healthy men had fairly constant total activities and isoenzyme patterns. On the contrary, there were marked variations in total activity between successive samples of seminal fluid from men with diseases in their accessory genital glands.Separation and quantitative determination of the various isoenzymes revealed a constant pattern in specimens from the same donor. The LDHx-activity was correlated to sperm density. Many patients with hemospermia, acute or chronic bacterial prostatitis or ‘functional’ prostatitis had a marked increase of LDH5.The LDH activity was unchanged by storage at -20°C for 28 days but sh...

The determination of lactate dehydrogenase iso-enzymes using the microzone cellulose acetate system

o 1. A rapid and simple technique using the Beckman Microzone celluloseacetate system for the electrophoretic separation of serum lactate dehydrogenase isoenzymes is described. 2. The isoenzymes are determined using the coupled nitro-blue-tetrazoliumreaction followed by densitometry of the formazan bands. Up to eight sera can be analysed for lactate dehydrogenase in one hour. The method is compared with that of starch gel electrophoresis. 3. Isoenzyme studies of normal individuals and patients are reported.

Lactic dehydrogenase isoenzymes in the aortic wall

Summary LDH isoenzymes were investigated by the method of electrophoresis in agar-gel and tetrazolium detection (INT or nitro-BT were used) in supernatants of the homo-genates of aortae (intima-media samples) of the followingspecies: rat, rabbit, guinea-pig, pig, cock, duck, and man. In the aortic wall of the investigated species we found marked differences in the distribution pattern of LDH isoenzymes which did not correspond to their behaviour in other organs. The relative values of the faster migrating portions in the adventitia of the human aorta were higher than in the intima or media. Ln plaques slower migrating parts were increased in comparison with the unaffected intima. A shift towards the slow migrating portions was observed with increasing in age. The pattern of LDH isoenzymes in the aortic muscle cells is rather specific and can be hardly compared with that of smooth muscles in other organs. Hormonal control of LDH isoenzymes in rat aortae is suggested from the increase of slower migrating parts in castrated and particularly in hypothyreoid animals. An opposite effect was observed after thyreoidine administration. The implications of these fmdings are discussed. The determination of isoenzymes represents a new approach to studies of the metabolism of the vascular wall. Their changes may become apparent before the ‘total’ activity of the respective en-zyme is affected.

Lactic dehydrogenase isoenzyme determination: Effect of incubation temperature

Lactic dehydrogenase isoenzyme determination: Effect of incubation temperature