Chronic Treatment with Low Doses of Estradiol Affects Pituitary and Thyroid Function in Young and Middle-aged Ovariectomized Rats
| Autor: | M. Böttner, Wolfgang Wuttke |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Thyroid Hormones
endocrine system Aging Pituitary gland medicine.medical_specialty medicine.drug_class Ovariectomy Thyroid Gland Thyrotropin Estrogen receptor Biology Polymerase Chain Reaction Rats Sprague-Dawley Internal medicine medicine Animals Estrogen Receptor beta RNA Messenger DNA Primers Base Sequence Dose-Response Relationship Drug Estradiol Thyroid Estrogen Receptor alpha medicine.disease Rats Menopause medicine.anatomical_structure Endocrinology Estrogen Pituitary Gland Ovariectomized rat Female Geriatrics and Gerontology Thyroid function Gerontology hormones hormone substitutes and hormone antagonists Endocrine gland |
| Zdroj: | Biogerontology. 6:261-269 |
| ISSN: | 1573-6768 1389-5729 |
| Popis: | Menopause marks the end of the reproductive life span of women and is characterized by a dramatic drop of circulating estrogen. Hormone replacement therapy (HRT) has been successfully used to treat the symptoms of menopause because estrogen has strong suppressive effects on climacteric complaints. As the hypothalamo-pituitary-thyroid axis is a target for estrogen action we assessed the effect of ovariectomy (OVX) and long-term (3 months) estradiol (E2) treatment by means of subcutaneously (s.c.) implanted silastic capsules on pituitary and thyroid function in middle-aged female rats. Our results demonstrate that s.c. administration of E2 resulted in physiological serum concentrations of E2. Upon OVX, ERbeta mRNA in the pituitary was induced and amounts of transcripts decreased after E2 administration. Implanted E2 capsules led to a reduction of ERalpha mRNA in the pituitary. E2 treatment attenuated the OVX-induced increases in TSHbeta and TSHalpha mRNA. Chronic E2 treatment reduced total T4 levels in OVX animals. TSH and total T3 serum levels were not altered upon E2 treatment. Taken together, our results clearly demonstrate that both, the pituitary and the thyroid of middle-aged rats remain susceptible to the influence of OVX and E2 treatment. |
| Databáze: | OpenAIRE |
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