Effects of ovariectomy on aggregation, secretion, and metalloproteinases in porcine platelets

Muthuvel Jayachandran, Whyte G. Owen, Virginia M. Miller

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Differences in the aggregation and release of growth factors including matrix metalloproteinases (MMPs) after loss of ovarian hormones could contribute to an exaggerated response to injury in arteries of ovariectomized animals. Therefore, experiments were designed to compare aggregation, dense granular ATP release, expression of MMPs (MMP-2, MMP-9, and MMP-14) and tissue inhibitors of metalloproteinase (TIMP-1 and TIMP-2) in circulating platelets from sexually mature (7 mo old) gonadally intact and ovariectomized (4 wk) female pigs. Numbers of circulating platelets did not change after ovariectomy, but the percentage of reticulated platelets increased significantly. Platelet aggregation and dense granular ATP secretion also increased significantly with ovariectomy. In platelet lysates, active MMP-2 increased, whereas MMP-14 significantly decreased, after ovariectomy; the expression of TIMP-1, TIMP-2, and P-selectin did not change. These results suggest that platelet turnover, aggregation, and ATP secretion increase with ovariectomy. Also, ovarian hormones selectively regulate the expression and activity of MMPs in porcine platelets. Increased platelet aggregation and activity of MMP-2 would alter platelet-platelet and platelet-vessel wall interactions, contributing to an exaggerated response to injury with loss of ovarian hormones.

Original languageEnglish (US)
Pages (from-to)H1679-H1685
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5 53-5
StatePublished - May 1 2003


  • ATP secretion
  • Estrogen
  • Hemostasis
  • Thrombosis
  • Tissue inhibitors of matrix metalloproteinase

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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