Progesterone and modulation of endothelium-dependent responses in canine coronary arteries

V. M. Miller, P. M. Vanhoutte

Research output: Contribution to journalArticle

188 Scopus citations

Abstract

Chronic treatment with estrogens enhances some endothelium-dependent relaxations. Whether or not progesterone would exert a similar effect is unknown. Experiments were designed to determine the effect of chronic treatment with progesterone on endothelium-dependent responses. Adult female dogs were ovariectomized and pellets containing carrier substance, estrogen, progesterone, or estrogen plus progesterone were implanted subcutaneously. After 14-21 days coronary arteries were removed, cut into rings, and suspended for the measurement of isometric force in organ chambers in the presence of indomethacin. Endothelium-dependent relaxations to ADP, bradykinin, or the calcium ionophore did not differ among groups. However, relaxations to acetylcholine and to the α2-adrenergic agonist BHT-920 were greater in the estrogen-treated group than in the estrogen plus progesterone-treated group. In rings without endothelium, relaxations to nitric oxide and isoproterenol did not differ among groups. However, relaxations of the smooth muscle to ADP were greater in the progesterone-treated group than in the progesterone plus estrogen group. These results suggest that progesterone alone minimally affects endothelium-dependent responses. However, progesterone seems to antagonize the stimulatory effects of estrogen on two endothelium-dependent responses that are associated with pertussis toxin-sensitive guanine nucleotide regulatory proteins and the production of nitric oxide. These studies suggest that a specific receptor/second messenger system can be modulated by female reproductive steroid hormones.

Original languageEnglish (US)
Pages (from-to)R1022-R1027
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume261
Issue number4 30-4
DOIs
StatePublished - 1991

Keywords

  • BHT-920
  • G proteins
  • acetylcholine
  • adenosine diphosphate
  • calcium ionophore A23187
  • guanine nucleotide regulatory proteins
  • hormones
  • nitric oxide
  • steroids
  • thrombin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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