Distribution of lactate dehydrogenase isoenzymes in coelomic fluid and fetal adnexae.

ABSTRACT

The objective of this study was to evaluate the distribution of lactate dehydrogenase isoenzymes in the human gestational sac. Total lactate dehydrogenase and its isoenzymes were measured in matched coelomic fluid and samples of villous and decidual tissues collected at the time of pregnancy termination in a group of 16 healthy women who were between 7 and 12 weeks of gestation. In addition intact secondary yolk sacs (n = 2) and fragments of fetal liver (n = 3) were collected. For comparison, samples of placental tissue, amniotic membrane and chorion obtained at term, were also investigated. In early pregnancy, H-type lactate dehydrogenase isoenzymes predominate in placental villous tissue and coelomic fluid, whereas M-type lactate dehydrogenase isoenzymes predominate in extracts of decidua, secondary yolk sac and fetal liver. These results highlight the important contribution of placental bioproducts to the constitution of the coelomic fluid. We observed also that placental patterns of lactate dehydrogenase isoenzymes change between the first and the third trimester of gestation, from the H-type to the M-type lactate dehydrogenase isoenzymes. We suggest that the lactate dehydrogenase pattern might be an indicator of proliferative or differentiative potential of the trophoblastic cells throughout pregnancy.