Concentrations of PGF-2  and PGE-2 in the uterine venous blood of rabbits during pseudopregnancy and pregnancy

Abstract

Peripheral plasma progesterone concentrations in intact and hysterectomized pseudopregnant rabbits decreased from Day 14. The rate of decrease in intact, but not in hysterectomized, rabbits accelerated on Day 17 and was associated with an increase in PGF-2 alpha levels in the uterine venous plasma. There was no change in uterine PGE-2 output during pseudopregnancy. In pregnant rabbits, peripheral plasma progesterone concentrations remained high up to Day 30, and there was no increase in uterine venous plasma levels of PGF-2 alpha on Day 17, PGF-2 alpha levels were elevated in uterine venous plasma on Day 25 of pregnancy, but there was no concurrent decline in plasma progesterone concentrations. Uterine venous plasma levels in PGE-2 increased markedly after Day 11 of pregnancy and reached very high concentrations in some rabbits.

Relative roles of oestradiol and of the uterus in the maintenance of the corpus luteum in the pseudopregnant brown hare (Lepus europaeus)

“…In the rabbit, removal of the uterus before ovulation or on Day 4, 8 or 12 of pseudo¬ pregnancy increases luteal life-span by 6-10 days beyond its normal duration (Scott & Rennte, 1970;Kelley & Brinkley, 1971;Hoffman et al, 1973;Hilliard et al, 1974;Satoh et al, 1980;Lytton & Poyser, 1982). However, in pseudopregnant rabbits bearing oestradiol capsules, the uterus may exert inhibitory and stimulatory influences on the responsiveness of the corpus luteum to oestradiol (Miller & McLean, 1987).…”

Intraluteal regulation of prostaglandin F2α-induced prostaglandin biosynthesis in pseudopregnant rabbits

“…In fact, PGF2a has been identified as the main luteolysing factor of uterine origin in several non-primate mammals including the rabbit (O'Grady et al 1972, Keyes & Bullock 1974, Lytton & Poyser 1982, and PGE2 as an important luteoprotective factor with luteotrophic or antiluteolytic actions (Niswender et al 2000). In many species, the CL themselves synthesize PGF2a and PGE2 (Gobbetti et al 1999, Boiti et al 2000, Diaz et al 2002, Zerani et al 2005, whose production is regulated by a large array of local and systemic factors, suggesting a paracrine and autocrine role for these two PGs (Olofsson & Leung 1996, Davis & Rueda 2002, Diaz et al 2002, Wiltbank & Ottobre 2003, Arosh et al 2004, Boiti et al 2005.…”

Effects of age and steroid treatment on prostaglandin production by the rat uterus in relation to implantation

“…They were caged in small groups of 3-5 animals and studied at 4-5 months or 13-14 months of age when they weighed Mitchell, Poyser & Wilson, 1977) and 100 µ were set aside for measuring the protein content by the method of Lowry, Rosebrough, Farr & Randall (1951 Radioimmunoassay s. The antisera used in these assays were raised in rabbits in the Department of Pharmacology, University of Edinburgh. PGE-2 was measured using an antibody which shows cross-reactivity with PGE-1 (100%), PGA-2 (13-6%) and PGB-2 (260%) but has low crossreactivities with other PGs and their metabolites (Lytton & Poyser, 1982). The limit of detection was 25 pg/tube.…”

“…Therefore, it is probable that only PGE-2 and PGF-2a are being measured in the respective radioimmunoassays. 6-Keto-PGF-la and TXB-2 were measured by antibodies which have low crossreactivities with other PGs and PG metabolites (Poyser & Scott, 1980;Lytton & Poyser, 1982). The detection limits were 25 pg/tube and 30 pg/tube respectively.…”