EFFECTS OF PROSTAGLANDIN-F2-ALPHA (PGF(2-ALPHA)) ON SECRETION OF PREGNANCY-SPECIFIC PROTEIN-B (PSPB) AND PLACENTOME WEIGHTS IN INTACT OR OVARIECTOMIZED 90 TO 100 DAY PREGNANT EWES

Vehicle or 8 or 16 mg PGF(2 alpha)/58 kg/body weight (BW) was given in tramuscularly to intact or ovariectomized 90 to 100 day pregnant ewes in two separate experiments. Treatment with 8 mg PGF(2 alpha) in intac t 90 to 100 day pregnant ewes increased (P less than or equal to 0.05) placentome weights, but not in ovariectomized 90 to 100 day pregnant ewes (P greater than or equal to 0.05). Concentrations of PSPB in uter ine venous plasma of control 90 to too day intact pregnant ewes over t he 72 hour sampling period averaged 52+/-5 ng/ml. Profiles of PSPB in uterine plasma in the 16 mg PGF(2 alpha)/58 kg/BW-treated ewes differe d (P less than or equal to 0.05) from control or 8 mg PGF(2 alpha)-tre ated 90 to 100 day intact pregnant ewes. Pregnancy specific protein B was increased (P less than or equal to 0.05) at 64 hr in intact 90 to 100 day pregnant ewes by treatment with 8 mg PGF(2 alpha)/58 kg/BW. Th ere was a quadratic increase (P less than or equal to 0.09) in PSPB in uterine venous plasma of all three treatment groups of intact 90 to 1 00 day pregnant ewes. Concentrations of PSPB in uterine venous plasma of control 90 to 100 day ovariectomized pregnant ewes over the 72 hr t reatment period averaged 90+/-5 ng/ml. Profiles of PSPB did not differ among the vehicle, 8 mg PGF(2 alpha) or 16 mg PGF(2 alpha)-treated ov ariectomized 90 to 100 day pregnant ewes. There was a quadratic increa se (P less than or equal to 0.10) in PSPB in uterine venous plasma of ovariectomized 90 to 100 day pregnant ewes treated with 8 or 16 mg PGF (2 alpha)/58 kg/BW. It is suggested that PSPB may have a role in regul ating placental steroidogenesis.