Apoptotic cell death of oestrogen activated lactotrophs induced by tamoxifen
| Autor: | Maria del Pilar Aoki, Cristina Alicia Maldonado, Agustín Aoki, Elsa Margarita Orgnero |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
endocrine system
medicine.medical_specialty Pituitary gland Programmed cell death Population Apoptosis Stimulation Biology Prolactin cell Internal medicine In Situ Nick-End Labeling medicine Animals Rats Wistar skin and connective tissue diseases education Cells Cultured Drug Implants education.field_of_study Estradiol Estrogen Antagonists Cell Biology General Medicine Immunohistochemistry Prolactin Rats Cell biology Microscopy Electron Tamoxifen medicine.anatomical_structure Endocrinology Pituitary Gland Female Tumor Suppressor Protein p53 Developmental Biology medicine.drug |
| Zdroj: | Tissue and Cell. 35:143-152 |
| ISSN: | 0040-8166 |
| DOI: | 10.1016/s0040-8166(03)00013-2 |
| Popis: | Stimulation and inhibition of lactotroph cells cause remarkable morphological and functional changes. In keeping with these changes, the size of the lactotroph cell population undergoes striking alterations due to proliferation or cell death. Factors involved in the induction of apoptosis of pituitary cells are not well established. We demonstrated earlier that oestrogens prevent lactotroph cells of female rats to die by apoptosis induced by bromocryptine treatment, a fact that can be reversed in ovariectomised rats. In this study, we developed experimental models for in vivo and in vitro studies to gain further insight on the survival effect of oestrogens on lactotrophs. In rats pretreated with oestrogens, tamoxifen generates a massive cell death by apoptosis as validated by the TUNEL technique and DNA electrophoresis of pituitary gland. On electron microscope observations, numerous lactotrophs exhibited progressive morphological changes in the nuclei compatible with the apoptotic process. The cells remaining intact also exhibit signs of inhibition due to a significant transformation of regular lactotrophs in atypical subtypes. In pituitary cell cultures exposed to tamoxifen and oestrogen simultaneously, most of the lactotrophs displayed features of apoptosis in the nucleus. The present reports gathered new evidences on the apoptogenic potential of tamoxifen on lactotroph cells, and corroborates the contribution of oestrogens to sustain both a balanced population of lactotrophs and a competent secretory activity. The concept that opposed activities, such as inhibition and stimulation, can activate apoptosis is also strengthen by these observations. |
| Databáze: | OpenAIRE |
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