L.D.H. and L.D.H. isoenzymes of the intra-uterine secretions of the cow during the estrous cycle

Uterine secretions were collected from 20 mature cows during estrus (day 0), metestrus (day 5), diestrus (day 10) and proestrus (day-1). Lactate dehydrogenase (LDH) and LDH isoenzymes activity were evaluated. No significant cyclic variations of LDH activity was found in the uterine secretions while the mean of the enzyme activity was higher during the estrogenic period of the cycle. The relative activity of LDH-1, LDH-2 and LDH-3 isoenzymes were higher during proestrus and estrus whereas LDH-5 activity was more important during metestrus. The LDH-3 seems to have the higher relative activity in uterine secretions of the cow.