Effects of prostaglandin F 2α (PGF 2α) on secretion of pregnancy specific protein B (PSPB) and placentome weights in intact or ovariectomized 90 to 100 day pregnant ewes

Abstract

Vehicle or 8 or 16 mg PGF 2α/58 kg/body weight (BW) was given intramuscularly to intact or ovariectomized 90 to 100 day pregnant ewes in two separate experiments. Treatment with 8 mg PGF 2α in intact 90 to 100 day pregnant ewes increased (P≤0.05) placentome weights, but not in ovariectomized 90 to 100 day pregnant ewes (P≥0.05). Concentrations of PSPB in uterine venous plasma of control 90 to 100 day intact pregnant ewes over the 72 hour sampling period averaged (52±5 ng/ml). Profiles of PSPB in uterine plasma in the 16 mg PGF 2α/58 kg/BW-treated ewes differed (P≤0.05) from control or 8 mg PGF 2α-treated 90 to 100 day intact pregnant ewes. Pregnancy specific protein B was increased (P≤0.05) at 64 hr in intact 90 to 100 day pregnant ewes by treatment with 8 mg PGF 2α/58 kg/BW. There was a quadratic increase (P≤0.09) in PSPB in uterine venous plasma of all three treatment groups of intact 90 to 100 day pregnant ewes. Concentrations of PSPB in uterine venous plasma of control 90 to 100 day ovariectomized pregnant ewes over the 72 hr treatment period averaged (90±5 ng/ml). Profiles of PSPB did not differ among the vehicle, 8 mg PGF 2α or 16 mg PGF 2α-treated ovariectomized 90 to 100 day pregnant ewes. There was a quadratic increase (P≤0.10) in PSPB in uterine venous plasma of ovariectomized 90 to 100 day pregnant ewes treated with 8 or 16 mg PGF 2α/58 kg/BW. It is suggested that PSPB may have a role in regulating placental steroidogenesis.