Lactate Dehydrogenase in Human Seminal Plasma

Abstract

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 LDH_x-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 showed a rapid deterioration at + 4°C.

Key Words:

• Lactate dehydrogenase
• prostate
• semen
• spermatozoa