ACTIVITY OF PLACENTAL 15-HYDROXY-PROSTAGLANDIN DEHYDROGENASE IN COWS WITH AND WITHOUT RETAINED FETAL MEMBRANES

The aim of the following study was to test the hypothesis that an incr eased local catabolism of prostaglandin F-2 alpha might at least in pa rt be responsible for the lower placental tissue concentration of PGF( 2 alpha) found in cows with retained fetal membranes (RFM) compared wi th that of cows without RFM. Activity of 15-hydroxy-prostaglandin dehy drogenase (15-PGDH) was measured in fetal and maternal placental tissu e from cows with spontaneous parturition at term, with Cesarian sectio n at term as well as before term either without (Groups A, C, E) or wi th RFM (Groups B, D, F), respectively. Furthermore, the concentration of progesterone and total estrogens in peripheral blood and degree of placental maturation were determined at the time of tissue sampling. A ctivity of 15-PGDH was higher in fetal part of the placenta than in th e maternal part (P<0.0001). In Groups A and C, enzyme activity was hig her than in Groups E and F (P<0.05). Enzyme activity in fetal and mate rnal placental tissue was positively correlated. A negative correlatio n was found between enzyme activity in maternal placental tissue and c oncentration of progesterone, and between concentration of progesteron e and total estrogen. Degree of placental maturation was lower in cows with RFM than without RFM. Furthermore, degree of placental maturatio n was lower in cows calving before term than in cows delivering at ter m. In conclusion, an increased local catabolism of PGF(2 alpha) might not be involved in lowering PGF(2 alpha) concentration in placental ti ssue from cows with RFM. Activity of 15-PGDH seems to be influenced by stage of gestation and hormonal environment.