Effects of Ovariectomy and Steroid Treatment on Hypophyseal Sensitivity to Purified LH-Releasing Factor (LRF)
| Autor: | Samuel M. McCann, C. P. Fawcett, C. Libertun, K. J. Cooper |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
medicine.medical_specialty
Pituitary gland Time Factors medicine.drug_class In Vitro Techniques Gonadotropin-Releasing Hormone chemistry.chemical_compound Endocrinology In vivo Internal medicine medicine Animals Endocrine system Castration Progesterone Dose-Response Relationship Drug Estradiol business.industry Ovary Luteinizing Hormone Rats medicine.anatomical_structure chemistry Estrogen Hypothalamus Pituitary Gland Ovariectomized rat Estradiol benzoate Female Follicle Stimulating Hormone Luteinizing hormone business hormones hormone substitutes and hormone antagonists |
| Zdroj: | Endocrinology. 94:518-525 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo-94-2-518 |
| Popis: | The sensitivity of the pituitary gland to partially purified LRF was investigated both in vivo and in vitro. LRF produced an increasein, plasma LH but not FSH in vivo, but it increased the release of both hormones from anteriorpituitaries incubated in vitro. Ovariectomy appeared to lower sensitivity below that encountered in proestrouS animals, but treatment of ovariectomized animals with 50 μg of estradiol benzoate subcutaneously 3 days before greatly enhanced the sensitivity to LRF both in vivo and in vitro. Treatment of ovariectomized animalswith 25 mg of progesterone in the presence or absence of estrogen failed to modify the responsiveness of the glands. Sensitization of the glands by estrogen was associated with a decline inplasma levels, but no alteration in pituitary contentof LH. Hypothalamic gonadotropin-releasingactivity was reduced by estrogen and the ratio of FSH to LH-releasing activity was reduced suggestingthat estrogen preferentially reduces synthesisand/or release of FSH-releasing factor... |
| Databáze: | OpenAIRE |
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