| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
The effect was studied of repeated injections of oestradiol-17β (5, 10, 25, 50 µg) given for various lengths of time (3, 5, 9 days) on total cell content of oestrogen receptors and cytosol progesterone receptors in the uteri of ovariectomized rats. An additional group of rats was injected daily with 50 µg oestradiol benzoate (OB) for 9 days in order to achieve a more sustained concentration of oestradiol in the blood. Injections were begun 24 h after ovariectomy and the rats were killed 24 h after the last injection. Daily administration of 5 µg oestradiol prevented the initial transient rise in oestrogen receptors which was observed in the uteri of untreated rats after ovariectomy. Repeated injections of 10 µg oestrogen produced an initial lowering in oestrogen receptors after 3 days of treatment which was followed by a prompt rise at 5 and 9 days when treatment was continued. A significant reduction in oestrogen receptors occurred at all times studied when rats were injected daily with 25 and 50 µg oestradiol. A more profound reduction in oestrogen receptors was observed in the group of rats treated for 9 days with 50 µg OB. Synthesis of progesterone receptors was stimulated by all doses of oestrogen studied. Concentrations of progesterone receptors were significantly higher after 3 and 5 days of treatment with 25 and 50 µg oestrogen. After 9 days of treatment, however, concentrations of progesterone receptors were virtually identical in all treated groups, including the group treated with OB. We have concluded that large doses of oestrogen significantly decrease oestrogen receptor content in the rat uterus, especially when OB is used. The degree of reduction, however, is only moderate under these experimental conditions and is insufficient to inhibit synthesis of progesterone receptors.
This article has been cited by other articles:
|
|
 |
|
  A. Gordon, J. C Garrido-Gracia, R. Aguilar, C. Bellido, J. A G. Velasco, Y. Millan, M. Tena-Sempere, J. Martin de las Mulas, and J. E Sanchez-Criado The ovary-mediated FSH attenuation of the LH surge in the rat involves a decreased gonadotroph progesterone receptor (PR) action but not PR expression J. Endocrinol., March 1, 2008; 196(3): 583 - 592. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J Varayoud, J G Ramos, L Monje, V Bosquiazzo, M Munoz-de-Toro, and E H Luque The estrogen receptor {alpha} {Sigma}3 mRNA splicing variant is differentially regulated by estrogen and progesterone in the rat uterus J. Endocrinol., July 1, 2005; 186(1): 51 - 60. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G.-S. Lee, K.-C. Choi, H.-J. Kim, and E.-B. Jeung Effect of Genistein As a Selective Estrogen Receptor Beta Agonist on the Expression of Calbindin-D9k in the Uterus of Immature Rats Toxicol. Sci., December 1, 2004; 82(2): 451 - 457. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Cotroneo and C. A. Lamartiniere Pharmacologic, but Not Dietary, Genistein Supports Endometriosis in a Rat Model Toxicol. Sci., May 1, 2001; 61(1): 68 - 75. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Yoshida, R. R. Newbold, and D. Dixon Abnormal Cell Differentiation and p21 Expression of Endometrial Epithelial Cells Following Developmental Exposure to Diethylstilbestrol (DES) Toxicol Pathol, March 1, 2000; 28(2): 237 - 245. [Abstract] [PDF]
|
|
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
