Prostacyclin biosynthesis by cultured human myometrial smooth muscle cells: Dependency on arachidonic or linoleic acid in the culture medium

Mackenzie, L. W.; MacDonald, Paul C.; Milewich, Leon; Casey, M.Linette

doi:10.1016/0002-9378(88)90557-1

Cited by 8 publications

(1 citation statement)

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“…It is interesting to note in this respect that DEX and P 4 have comparable inhibitory effects. DEX is recognized as a potent inhibitor of PGI 2 production in human myometrium [22]. Because the levels of PGI synthase are comparable in the two muscle layers and do not vary with steroid treatments, it is tempting to conclude that the regulation of PGI 2 production in the myometrium is regulated through the expression of PGHS-2.…”

Section: Discussionmentioning

confidence: 99%

Prostaglandin G/H Synthase (PGHS)-2 Expression in Bovine Myometrium: Influence of Steroid Hormones and PGHS Inhibitors1

Doualla-Bell

Guay

Bourgoin

et al. 1998

Biology of Reproduction

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Prostaglandins (PGs) are important mediators regulating uterine functions during the reproductive process. The objective of this study was to examine, in myocytes from the circular and longitudinal layers of bovine myometrium, the relative levels of mRNA and proteins corresponding to the gene expression of key enzymes (phospholipase A2; prostaglandin G/H synthase-1 [PGHS-1]; prostaglandin G/H synthase-2 [PGHS-2]; prostaglandin I2 synthase) involved in PG biosynthesis. We examined the influence of estradiol-17beta and progesterone on the expression and activity of these enzymes. Treatment of myocytes with progesterone (P4: 10 nM, 24 h) in the absence or presence of estradiol-17beta (E2: 1 nM, 72 h) suppressed PG biosynthesis by approximately 60% in both myometrial layers. No significant effect was observed after E2 treatment. The combined effect of E2 and P4 on PG accumulation was correlated with the modulation of PGHS-2 protein and mRNA levels in the two myometrial layers without affecting other enzymes of the PG cascade. Selective or nonselective inhibition of PGHS activity with CGP 28238 (PGHS-2-specific; a product from Ciba-Geigy: 6-[2, 4-difluorophenoxy]-5-methyl-sulfonylamino-1-indanone) or indomethacin (PGHS-1 and -2) reduced prostacyclin accumulation (measured as 6-keto-PGF1alpha in the culture medium) in a dose-dependent manner in the two myometrial layers. A significant inhibitory effect was obtained at a low concentration of indomethacin (1 nM, p < 0.05) compared to CGP 28238 (10 nM, p < 0. 05). In both myometrial layers, the maximal effect of indomethacin and/or CGP 28238 on PG accumulation was observed at 100 nM and represented 85% and 65% inhibition, respectively. In the presence of phorbol 12-myristate (100 nM), CGP 28238 (10 nM) significantly suppressed PGHS-2 mRNA level by 44.80 +/- 7.67% (p < 0.01) and 27.83 +/- 7.62% (p < 0.05) in the longitudinal and circular layer, respectively. In contrast, indomethacin did not have any significant effect. These data constitute the first quantitative analysis of key enzymes involved in PG biosynthesis in separated myometrial layers. Furthermore, the results provide interesting information on the CGP 28238 drug modulating both enzymatic activity and mRNA expression of PGHS-2.

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Section: Discussionmentioning

confidence: 99%