Upregulation of thrombomodulin antigen levels in U937 cells by combined stimulation with estradiol-17beta and vitamin K2 (menaquinone 4)

Estrogenic endocrine disruptors: Molecular mechanisms of action

A comprehensive summary of more than 450 estrogenic chemicals including estrogenic endocrine disruptors is provided here to understand the complex and profound impact of estrogen action. First, estrogenic chemicals are categorized by structure as well as their applications, usage and effects. Second, estrogenic signaling is examined by the molecular mechanism based on the receptors, signaling pathways, crosstalk/bypassing and autocrine/paracrine/homeostatic networks involved in the signaling. Third, evaluation of estrogen action is discussed by focusing on the technologies and protocols of the assays for assessing estrogenicity. Understanding the molecular mechanisms of estrogen action is important to assess the action of endocrine disruptors and will be used for risk management based on pathway-based toxicity testing.

Effects of para-nonylphenol on 92 kDa gelatinase secretion by human peripheral lymphocytes and U937 cells in vitro

Much attention has focused on environmental estrogenic chemicals such as para-nonylphenol which disrupt various tissues via the estrogen receptor. We studied effects of para-nonylphenol on gelatinase secretion by human lymphocytes in vitro. para-Nonylphenol (0.05-50 microM) dose dependently suppressed 92 kDa gelatinase secretion. The suppressive effect of 25 and 50 microM para-nonylphenol was completely blocked by tamoxifen. We also studied the effects of para-nonylphenol (0.05-50 microM) on 92 kDa gelatinase secretion by human leukemia U937 cells. para-Nonylphenol suppressed 92 kDa gelatinase secretion in a dose-dependent manner. The suppressive effect of 50 microM para-nonylphenol was completely blocked by tamoxifen. Estradiol did not significantly suppress 92 kDa gelatinase secretion. Our results suggest that para-nonylphenol suppressed 92 kDa gelatinase secretion via the estrogen receptor, however, para-nonylphenol interacts with the estrogen receptor in a manner distinct from estradiol. As this assay system is simple and rapid, it may prove useful to evaluate toxic effects of para-nonylphenol on human blood cells.