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Estradiol Increases the Expression of TNF-alpha and TNF Receptor 1 in Lactotropes.

Authors: Zaldivar, V  Magri, ML  Zarate, S  Jaita, G  Eijo, G  Radl, D  Ferraris, J  Pisera, D  Seilicovich, A 
Citation: Zaldivar V, etal., Neuroendocrinology. 2011;93(2):106-13. Epub 2011 Jan 20.
Pubmed: (View Article at PubMed) PMID:21252492
DOI: Full-text: DOI:10.1159/000323760

Background: Estrogens are recognized modulators of pituitary cell renewal, sensitizing cells to mitogenic and apoptotic signals. Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that plays an important role in tissue homeostasis modulating cell proliferation, differentiation and death. We previously demonstrated that TNF-alpha-induced apoptosis of anterior pituitary cells from female rats is estrogen-dependent and predominant in cells from rats at proestrus when estradiol levels are the highest. Aims: Considering that one of the mechanisms involved in the apoptotic action of estrogens can result from increased expression of cytokines and/or their receptors, the aim of the present study was to evaluate the effect of estrogens on the expression of TNF-alpha and its receptor, TNF receptor 1 (TNFR1), in anterior pituitary cells. Methods/Results: TNFR1 expression, determined by Western blot, was higher in anterior pituitary glands from rats at proestrus than at diestrus. Incubation of anterior pituitary cells from ovariectomized rats with 17beta-estradiol enhanced TNFR1 protein expression. As determined by double immunocytochemistry, the expression of TNF-alpha and TNFR1 was detected in prolactin-, GH-, LH- and ACTH-bearing cells. 17beta-estradiol increased the percentage of TNF-alpha and TNFR1-immunoreactive lactotropes but did not modify the number of GH-bearing cells expressing TNF-alpha or TNFR1. Conclusion: Our results demonstrate that estradiol increases the expression of TNF-alpha and TNFR1 in anterior pituitary cells, especially in lactotropes. The sensitizing action of estrogens to proapoptotic stimuli at proestrus in the anterior pituitary gland may involve changes in the expression of the TNF-alpha/TNFR1 system.

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RGD Object Information
RGD ID: 5130896
Created: 2011-04-13
Species: All species
Last Modified: 2011-04-13
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.