Resumo

POLINI, Nélida Nélida; MASSHEIMER, Virginia Laura  e  SELLES, Juana. Effects of progesterone on platelet aggregation and rat aorta eicosanoid production. Acta bioquím. clín. latinoam. [online]. 2004, vol.38, n.3, pp.281-287. ISSN 0325-2957.

Using rat aortic tissue, the non genomic action of progesterone (Pg) on nitric oxide (NO), prostacyclin (PGI₂), and tromboxane (Tx) synthesis and its relationship with platelet aggregation were studied. Treatment of female rat aortic rings (RAS) with Pg induced a dose-dependent inhibition of platelet aggregation (IPA), which was partially abolished when RAS were treated in the presence of the specific NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME). This observation would indicate that the inhibition of platelet aggregation (PA) resulted partially dependent on NOS stimulation by the hormone. Pg also produced a dose-dependent increase in PGI₂ synthesis (42 at 182% respect to control), but no changes in Tx liberation by aorta was observed, at any concentration of Pg used. RAS preincubation with indomethacine, a COX inhibitor, partially reduced Pg antiaggregatory effect, suggesting that the inhibition of PA induced by hormone is also dependent on PGI₂ generation. These results provide evidence that Pg modulates PA involving NO and PGI₂ metabolic pathways.

Palavras-chave : Platelet aggregation; Progesterone; Nitric oxide; Prostacyclin; Aterosclerosis; Ovarian hormones; Aorta.

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