The lactate dehydrogenase activity and isoenzyme pattern of normal and hypokinetic human tendons.

The LDH specific activity and the LDH isoenzyme pattern of eleven pairs of different normal tendons were compared with hypokinetic tendons. The LDH specific activity of hypokinetic tendons was 13--66% of the specific activity of normal tendons. The isoenzyme pattern of hypokinetic tendons altered in such a way that--with one exception--the ratio of LDH-5 and LDH-4 decreased and the ratio of LDH-1, LDH-2, and LDH-3 increased and, as a consequence, the amount of the M subunit decreased.