dinoprost and epostane

Prostaglandin F2alpha (PGF) causes luteolysis of the pig corpus luteum (CL) only after Day 12 of the estrous cycle. Recent evidence indicates that progesterone (P4) may protect the CL from cell death. The present study tested the hypothesis that acute inhibition of P4 by treatment with epostane (EPO; 3betaHSD inhibitor) in CL lacking luteolytic capacity (Day 9 CL) will allow PGF to induce responses associated with luteolysis. Multiple PGF-induced responses were evaluated, including genes involved in production of PGF and estradiol-17beta, apoptosis (caspase 3), and transcription (FOSB). These responses are associated with PGF-induced luteolysis and do not normally occur in CL lacking luteolytic capacity. Animals on Day 7 after estrus were divided into four groups: 1) control (C), 2) PGF, 3) EPO, and 4) PGF plus EPO (PGF+EPO). Treatment with EPO (10 mg/kg) or vehicle was given every 12 h for 36 h. Treatment with PGF (25 mg) or vehicle was given at 38 h, and CL were collected from all animals at 48 h. Some CL from each animal were frozen in liquid nitrogen for mRNA and protein analysis. Remaining CL were incubated in media for 2 h for determination of P4 and PGF production. EPO dramatically decreased production of P4 by luteal tissue (ng/mg tissue) by 90% and 95% in EPO and PGF+EPO groups, respectively, compared to C (P < 0.01). Low production of PGF by luteal tissue was found in C, PGF, and EPO groups; however, treatment with PGF+EPO dramatically increased (782%) luteal PGF production. Similar to intraluteal PGF production, increased mRNA for cyclooxygenase 2 (PTGS2) and phospholipase A2 (group IB; PLA2G1B) was found in the PGF+EPO, but not in the EPO or PGF, group. Aromatase (CYP19A1) mRNA was not induced by PGF or EPO; however, PGF+EPO caused a more than 40-fold increase in CYP19A1 mRNA (P < 0.01). CASP3 mRNA was increased (P < 0.01) by EPO (3.4-fold) and by PGF (2.7-fold) but was most dramatically increased by PGF+EPO (5.3-fold), whereas caspase activity was only increased by PGF (1.5-fold) or PGF+EPO (2.2-fold). Thus, these data support the hypothesis that elimination of the protective effect of intraluteal P4 does not directly cause luteolysis of the early CL but allows PGF to induce luteolytic responses in CL lacking luteolytic capacity.

Topics: Androstenols; Animals; Caspase 3; Corpus Luteum; Dinoprost; Female; Gene Expression Regulation; Luteolysis; Phosphoproteins; Progesterone; Proto-Oncogene Proteins c-fos; Swine

This study tested the hypotheses that prostaglandin (PG) F(2α) increases expression of genes related to recruitment of leukocytes in mature but not early corpus luteum (CL) and that insensitivity to PGF(2α) action in early CL is dependent on high intraluteal progesterone (P4) concentrations. Experiment 1 examined early (0.5 h) and late (10 h) in vivo effects of PGF(2α) on mature (d 17 of pseudopregnancy) and early (d 9) porcine CL. Real-time PCR was used to measure mRNA for chemokines (IL8, CXCL2, CCL2, CCL8, CCL4, CCL11) and chemokine receptors (CCR1, CCR2, CXCR2, CCR5). Western blotting was used to measure protein expression and phosphorylation of nuclear factor-κB proteins. Treatment with PGF(2α) for 10 h increased mRNA for almost all of these genes (all expect CXCL2 and CCL11) in d 17 CL but not d 9 CL. Treatment with PGF(2α) also led to greater phosphorylation of nuclear factor-κB-1A protein in d 17 than d 9 CL. Experiment 2 had a 2 × 2 factorial design with d 9 gilts treated or not treated with epostane (3β-hydroxysteroid dehydrogenase inhibitor to suppress intraluteal P4) and treated or not treated with PGF(2α). Treatment with PGF(2α) (10 h) or epostane alone did not induce expression of any of these genes in d 9 CL. However, PGF(2α) + epostane increased expression of all of these genes except CCL11. In conclusion, PGF(2α) increases mRNA for chemokines and chemokine receptors in mature CL with similar PGF(2α) effects induced in early CL if intraluteal P4 is suppressed prior to PGF(2α) treatment.

Topics: 3-Hydroxysteroid Dehydrogenases; Androstenols; Animals; Chemokines; Corpus Luteum; Dinoprost; Enzyme Inhibitors; Female; Luteinization; NF-kappa B; Phosphorylation; Progesterone; Protein Processing, Post-Translational; Pseudopregnancy; Random Allocation; Receptors, Chemokine; RNA, Messenger; Signal Transduction; Sus scrofa; Up-Regulation

In sheep parturition may be induced within 33 h in late gestation by inhibiting progesterone production with the 3 beta hydroxysteroid dehydrogenase inhibitor Epostane. Its effect has now been investigated in ewes carrying adrenalectomised (n = 5), hypophysectomised (n = 4) or intact (n = 5) fetuses to determine the role of the fetal adrenal during this type of maternally-induced delivery. Epostane was infused i.v. (1.5 mg/kg) into each group of ewes at 137-156 days gestation. Fetus and mother were sampled from the time of administration until delivery. Measurements of plasma ACTH, cortisol, progesterone and PGF2 alpha metabolite (PGFM) were made and intrauterine pressure was monitored. Epostane induced delivery significantly later in the adrenalectomised (44 h) and hypophysectomised (52 h) animals compared with the controls (33 h). The drop in maternal plasma progesterone was similar in all 3 groups, but the subsequent increases in arterial and uterine venous PGFM were smaller in the adrenalectomised and hypophysectomised ewes than in the controls. The large escalation in fetal plasma cortisol before birth in controls was absent in adrenalectomised and hypophysectomised fetuses. The slight rises in plasma cortisol observed in the latter from about 24 h after Epostane, were related to the concomitant increases in maternal plasma levels (r = 0.76, P less than 0.01). No fetuses became hypoxic or acidotic during the period of induction despite the prolonged labour of hypophysectomised and adrenalectomised fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 3-Hydroxysteroid Dehydrogenases; Adrenal Glands; Adrenalectomy; Adrenocorticotropic Hormone; Androstenols; Animals; Dinoprost; Female; Fetal Blood; Hydrocortisone; Hypophysectomy; Labor, Induced; Pregnancy; Pregnancy Outcome; Progesterone; Sheep

The antiovulatory action of epostane, an inhibitor of 3 beta-hydroxysteroid dehydrogenase activity and progesterone synthesis, was studied in the immature rat. The ovulatory process was induced in 25-day-old rats by injecting them with hCG (10 IU, sc) 2 days after the animals had been primed with PMSG (10 IU). Epostane was administered at different times between 20 h before and 11 h after hCG. Maximum inhibition of ovulation occurred when the drug was given at 3 h after hCG. Epostane inhibited ovulation in a dose-dependent manner when administered in doses ranging from 1.0-50 mg/rat, while exogenous doses of progesterone restored the ovulation rate. A dose of 3.1 mg epostane/rat 3 h after hCG reduced ovarian progesterone levels within 15 min, but the production of this steroid rebounded within 2 h and approached normal levels by 12 h after hCG, i.e. when the follicles began to rupture in control animals. 17 beta-Estradiol synthesis was inhibited just as rapidly, but it remained suppressed for up to 12 h after hCG administration. The ovarian levels of prostaglandins E2 and F2 alpha decreased approximately 30% within 2 h after the administration of epostane, but such a moderate reduction in the synthesis of ovarian prostanoids is usually not sufficient to block ovulation. The results show that epostane has a rapid, but transient, effect on ovarian progesterone synthesis. The temporary decline in the local progesterone level is apparently sufficient to interfere with the normal sequence of metabolic events that lead to the rupture of follicles.

Topics: 3-Hydroxysteroid Dehydrogenases; Androstenols; Animals; Chorionic Gonadotropin; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Estradiol; Female; Ovary; Ovulation; Progesterone; Rats; Rats, Inbred Strains

Epostane, a competitive inhibitor of 3 beta-HSD was administered intravenously to a pregnant mare between 292 and 330 days of gestation at doses of 1-3 mg/kg/min. Plasma progesterone concentrations fell rapidly during epostane infusion in both the artery and uterine vein and remained significantly depressed for 4-5 h after the start of infusion. The venous arterial (V-A) plasma concentration difference in progesterone across the uterus also decreased significantly in response to epostane infusion. There were no significant changes in plasma progesterone or in the V-A concentration difference in control animals infused with vehicle alone. The plasma concentration of total unconjugated oestrogens in the uterine vein was reduced after administration of epostane but remained virtually unchanged in the control experiments. Uterine venous plasma concentrations of PGFM did not change significantly in the control or epostane-treated animals. Arterial plasma cortisol levels fell initially after epostane treatment but then rose to values significantly greater than before infusion. A similar increase in arterial plasma cortisol was observed in the control animals. None of the mares delivered after epostane treatment even at the highest dose. These observations demonstrate that inhibition of 3 beta-HSD alters steroidogenesis but has little effect on the length of gestation in the pregnant mare.

Topics: 3-Hydroxysteroid Dehydrogenases; Androstenols; Animals; Dinoprost; Estrogens; Female; Horses; Hydrocortisone; Pregnancy; Pregnancy, Animal; Progesterone; Prostaglandins F