The effect of training and detraining on lactate dehydrogenase isoenzymes in the horse

In the horse, total LDH activity increased with training and the H and M subunit activity parallelled this increase. It is suggested that these increases are in response to a stimulus from the type of training program utilised. The first half of a detraining program decreased the activity of the H and M subunits as might be expected. A sharp rise in the total LDH and the M subunit activity occurred during the latter half of the detraining program. This unexpected increase may be due to relatively more hypoxic conditions prevailing in the muscle during the detraining period.