Prostaglandin production by the early pregnant guineapig uterus in relation to implantation and luteal maintenance, and the effect of oestradiol

Abstract

The outputs of prostaglandin (PG) F-2 alpha and PGE-2, but not of 6-oxo-PGF-1 alpha, from the guinea-pig uterus were significantly lower on Days 7 and 15 of pregnancy than on the corresponding days of the cycle. Uterine PGF-2 alpha output increased 28-fold between Days 7 and 15 of the cycle but only 4- to 5-fold between these same days of pregnancy. Uterine PGE-2 and 6-oxo-PGF-1 alpha outputs increased 2- to 3-fold between Days 7 and 15 of the cycle and of pregnancy. Endometrial PGF-2 alpha synthesizing capacity was 60-70% lower on Days 7 and 15 of pregnancy than on the corresponding days of the cycle, although it increased 2-fold and 2.5-fold between these days of pregnancy and of the cycle, respectively. Endometrial PGE-2 and 6-oxo-PGF-1 alpha synthesizing capacities showed no significant variation amongst Days 7 and 15 of the cycle and of pregnancy, except that endometrial PGE-2 synthesizing capacity was lower on Day 7 of the cycle. Oestradiol treatment (10 micrograms s.c. daily from Days 10 to 14 of pregnancy) did not affect plasma progesterone concentrations, uterine 6-oxo-PGF-1 alpha output, and endometrial PGF-2 alpha, PGE-2 and 6-oxo-PGF-1 alpha synthesizing capacities in 9/12 guinea-pigs when examined on Day 15. Uterine PGF-2 alpha and PGE-2 outputs increased 3- and 1.5-fold, respectively, in these guinea-pigs, but were still much lower than the outputs from the Day-15 non-pregnant uterus. The pregnancies appeared unaffected in these oestradiol-treated guinea-pigs. In the other 3 oestradiol-treated animals, uterine PGF-2 alpha output was 20- to 30-fold higher than in untreated, pregnant guinea-pigs on Day 15, and 2- to 3-fold higher than in Day-15 non-pregnant guinea-pigs. Uterine PGE-2 and 6-oxo-PGF-1 alpha outputs also tended to be higher in these treated guinea-pigs. In these 3 guinea-pigs, endometrial PGF-2 alpha, PGE-2 and 6-oxo-PGF-1 alpha synthesizing capacities were 4.0-, 3.4- and 2.5-fold higher, respectively, than in untreated, pregnant guinea-pigs on Day 15, and tended to be higher than in Day-15 non-pregnant guinea-pigs. Plasma progesterone concentrations were much lower in these 3 animals than in the other 9 treated with oestradiol, and also much lower than in untreated, pregnant guinea-pigs on Day 15.(ABSTRACT TRUNCATED AT 400 WORDS)

Prostaglandin output from the early pregnant rat uterus superfused in vitro, and the effect of A23187 and trifluoperazine

“…Similar actions of A23187 have been reported for the non-pregnant and early pregnant guinea-pig uterus (Poyser & Brydon, 1983;Poyser, 1984a), an effect which is dependent upon extracellular Ca2+ (Poyser, 1984b). A23187 has been reported to stimulate 6-oxo-PGF-la output from the myometrium, but not from the endometrium, of rat uteri superfused in vitro (Campos, Liggins & Seamark, 1980).…”

“…A blood sample was collected into a heparinized (20 U/ml) syringe from the incised neck of each rat. The blood was centrifuged at 2500 g, and the plasma was withdrawn and stored at -20°C before being assayed for progesterone as described previously (Poyser & Horton, 1975;Fenwick, Jones, Naylor, Poyser & Wilson, 1977;Poyser, 1984a). All the samples were measured in 2 assays.…”

“…After collection, PGs were extracted and stored and the amounts of PGF-2a, PGE-2 and 6-oxo-PGF-la present in the samples were measured by radioimmunoassay as described previously (Poyser, 1984a). The intra-assay coefficients of variation, calculated from the variation between the duplicate results obtained, were 9-8% (PGF-2oc), 10-4% (PGE-2) and 10-7% (6-oxo-PGF-la).…”

Effect of trifluoperazine, a calmodulin antagonist, on prostaglandin output from the guinea-pig uterus

“…The two ethyl acetate fractions were com¬ bined and evaporated to dryness on a rotary evaporator at 45°C. Each extract was re-dissolved in 10 ml ethyl acetate and stored at -20°C before the amounts of PGF-2a, PGE-2 and 6-oxo-PGF-la present were measured by radioimmunoassay (RIA) as described previously (Poyser, 1984b). During the periods of superfusate collection, the tone of the uterus was noted.…”

Perfil do RNAm da proteína transportadora de prostaglandina (PGT) no endométrio equino in vivo e sobre influência embrionária in vitro

“…Porém, para Poyser (1984), a PGF 2α produzida pelo endométrio gestante não atinge a corrente circulatória por ser produzida em baixas quantidades, pois o autor encontrou que na porca cíclica a concentração intrauterina de PGF 2α aumenta 28 vezes entre o sétimo e o décimo quinto dia após ovulação, enquanto que na fêmea gestante este mesmo hormônio, durante o mesmo período, aumenta somente 4 a 5 vezes.…”