UTERINE OESTROGEN AND PROGESTERONE RECEPTORS IN THE OVARIECTOMIZED RAT

1981 ◽  
Vol 91 (2) ◽  
pp. 281-287 ◽  
Author(s):  
ANDREA MANNI ◽  
REBECCA BAKER ◽  
B. M. ARAFAH ◽  
O. H. PEARSON
Keyword(s):  
Progesterone Receptors ◽  
Total Cell ◽  
Ovariectomized Rats ◽  
Oestrogen Receptors ◽  
Rat Uterus ◽  
Experimental Conditions ◽  
Cell Content ◽  
Transient Rise ◽  
Additional Group ◽  
Oestradiol Benzoate

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.

PROGESTERONE-INDUCED OESTROGEN RECEPTORS IN THE RAT UTERUS

1978 ◽  
Vol 76 (1) ◽  
pp. 145-154 ◽  
Author(s):  
DOMINIQUE MARTEL ◽  
ALEXANDRE PSYCHOYOS
Keyword(s):  
Physicochemical Properties ◽  
Oestrogen Receptor ◽  
Sedimentation Coefficient ◽  
Kinetic Constants ◽  
Ovariectomized Rats ◽  
Oestrogen Receptors ◽  
Rat Uterus ◽  
Receptor Molecule

SUMMARY In ovariectomized rats progesterone acts like oestradiol at the endometrial, but not at the myometrial level, by increasing the number of oestrogen receptors in the cytoplasm. After 3 days of progesterone priming, the number of endometrial oestrogen receptors was found to be three times higher (P<0·05, Student's t-test) than control values. This progesterone-induced oestrogen receptor molecule appears identical in its physicochemical properties (sedimentation coefficient, kinetic constants, steroid specificity) to that induced in the endometrium and myometrium under the influence of oestradiol. However, in the myometrium progesterone acts antagonistically reducing significantly (P< 0·001, Student's t-test) the oestradiol-induced increase in the number of oestrogen receptors.

scholarly journals Gonadotropin-secreting cells in ovariectomized rats treated with different oestrogen receptor ligands: a modulatory role for ERβ in the gonadotrope?

2006 ◽  
Vol 188 (2) ◽  
pp. 167-177 ◽  
Author(s):  
J E Sánchez-Criado ◽  
J Martín de las Mulas ◽  
C Bellido ◽  
V M Navarro ◽  
R Aguilar ◽  
...  
Keyword(s):  
Oestrogen Receptor ◽  
Light And Electron Microscopy ◽  
Ovariectomized Rats ◽  
Secretory Process ◽  
Oestrogen Receptors ◽  
Receptor Ligands ◽  
Structural Reorganization ◽  
Relative Contribution ◽  
Oestradiol Benzoate ◽  
Lh Secretion

In the rat, oestrogen is a key regulator of gonadotrophin synthesis and release through activation of oestrogen receptors (ERs). Gonadotropes express α and β isoforms of ER and both can activate transcription in response to oestrogen. These experiments were aimed at evaluating the relative contribution of ERα and ERβ on gonadotrope morphology, progesterone receptor (PR) expression and LH secretion. Ovariectomized rats were daily injected over 3 days with 25 μg oestradiol benzoate, 0.3 or 1.5 mg of the selective ERα agonist propylpyrazole triol (PPT) with or without 1.5, 3.0 or 4.5 mg of the selective ERβ agonist diarylpropionitrile (DPN), DPN alone, and 0.3 or 3 mg of tamoxifen. Controls were given 0.2 ml oil. Serum concentration and pituitary content of LH, gonadotrope PR expression, pituitary PR content, and gonadotrope morphology were analyzed by RIA, immunohistochemistry, Western blotting and light and electron microscopy, respectively. Results showed that PPT reversed all consequences of ovariectomy, DPN mimicked the effects of PPT except for its LH-releasing action and tamoxifen had ERα-like responses. When combined with PPT, DPN attenuated ERα effects without interfering with its LH-releasing activity. Oestradiol benzoate had similar effects to those of combined PPT and DPN. It is suggested that (i) the structural reorganization of the cytoplasmic organelles provided by oestrogen, and the shrinkage of the ovariectomy-induced hypertrophy of gonadotropes, which precedes the expression of PR, are evoked by ERα and modulated, in a ying–yang fashion, by ERβ; and (ii) the oestrogen-dependent exocytosis of LH, the final step in the secretory process, is dependent on ERα exclusively.

scholarly journals Oestrogen and progesterone receptors in chick oviduct chromatin after administration of oestradiol, progesterone or anti-oestrogen

1982 ◽  
Vol 204 (3) ◽  
pp. 653-662 ◽  
Author(s):  
M C Lebeau ◽  
N Massol ◽  
E E Baulieu
Keyword(s):  
Gene Regulation ◽  
Binding Sites ◽  
Single Injection ◽  
Progesterone Receptors ◽  
Biological Response ◽  
Micrococcal Nuclease ◽  
Oestrogen Receptors ◽  
Oestradiol Benzoate ◽  
S Peak ◽  
Two Peaks

Oestrogen-primed and withdrawn chicks were injected with oestradiol benzoate, progesterone, and/or the anti-oestrogens tamoxifen and 4-hydroxytamoxifen. Oestrogen receptors were studied in oviduct chromatin solubilized by mild digestion of purified nuclei with micrococcal nuclease. After a single injection of oestradiol benzoate, ultracentrifugation on sucrose gradients of chromatin extracts labelled with [3H]-oestradiol showed two peaks of oestradiol binding sites, sedimenting at 13-14 S and 7-8 S. After repeated injections of oestradiol benzoate, the 13-14 S peak increased more than the 7-8 S peak. After injection of anti-oestrogen alone or together with oestradiol benzoate, no [3H]oestradiol-binding or 4-hydroxy[3H]tamoxifen-binding peaks were detected in the chromatin. Injection of progesterone also produced an increase of the 13-14 S and 7-8 S chromatin oestradiol receptor. Progesterone receptor could only by detected in chromatin early after progesterone administration, and it sedimented in density gradients with the 12 S mononucleosome fraction. Tamoxifen injected together with progesterone gave higher levels of 13-14 S oestrogen binding sites than did progesterone alone. The presence of a 13-14 S peak of oestrogen binding sites in hormonal situations which promote a biological response in the chick oviduct, and the absence of this peak after administration of anti-oestrogens, suggest that this subfraction of chromatin contains elements involved in gene regulation.

PRE-TRAUMA OESTROGEN REQUIREMENTS FOR INDUCTION OF DECIDUALIZATION IN SPAYED, PROGESTERONE-TREATED RATS

1966 ◽  
Vol 53 (2) ◽  
pp. 212-224 ◽  
Author(s):  
Carla Rossi Cartoni ◽  
G. Bignami
Keyword(s):  
Single Dose ◽  
Hormonal Treatment ◽  
Normal Pregnancy ◽  
Carbonic Anhydrase Activity ◽  
The Other ◽  
Ovariectomized Rats ◽  
Uterine Weight ◽  
Experimental Conditions ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

ABSTRACT The formation of deciduomata was investigated in ovariectomized rats treated with various combinations of oestrogen and progesterone before traumatization. The hormonal treatment was kept constant for all groups of animals during the period between traumatization and autopsy (4 mg of progesterone and 0.2 μg of oestradiol benzoate daily). Uterine weight and carbonic anhydrase activity were measured 96 hours after trauma and compared with those of intact controls receiving traumatization on day 4 of pseudopregnancy. When a single dose of oestrogen was given on the day before traumatization, induction of decidualization was successful under a wide variety of experimental conditions (presence or absence of oestrogen »priming« before the beginning of the progesterone treatment; progesterone treatment of varying duration). On the contrary, treatment with divided doses of oestrogen, given for 3 days before trauma, allowed extensive decidualization only in rats »primed« with oestrogen, and traumatized on the fourth day of a progesterone treatment started 24 hours after vaginal keratinization. It appears therefore that only the »oestrogen surge« hypothesis of Shelesnyak and his collaborators can account for those conditions in which implantation occurs at variable intervals of time after the last oestrus (lactation, hypophyseal autotransplantation, administration of a tranquilizer and early ovariectomy followed by hormonal treatment). On the other hand, both the hypothesis of Shelesnyak and that proposed by Yochim & DeFeo (1963) (i. e. continuous secretion of small amounts of oestrogen during the first three days of pregnancy and pseudopregnancy) could account for the rapid waxing and waning of endometrial sensitivity to deciduoma-inducing stimuli observed in normal pregnancy and pseudo-pregnancy.

OESTROGEN RESPONSES OF RATS NEONATALLY STERILIZED WITH STEROIDS

1969 ◽  
Vol 45 (3) ◽  
pp. 415-420 ◽  
Author(s):  
T. R. WRENN ◽  
JOAN R. WOOD ◽  
J. BITMAN
Keyword(s):  
Testosterone Propionate ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Uterine Weight ◽  
Oestradiol Benzoate

SUMMARY At 75 days of age, female rats neonatally sterilized with oestradiol benzoate or testosterone propionate were compared with normal and ovariectomized rats with regard to their 6-hr. response to 0·2 μg. oestradiol 17β. The greatest increases in uterine weight, glucose and glycogen concentrations and per cent uterine water occurred in the ovariectomized animals. A marked oestrogen response also occurred in the animals neonatally sterilized with oestradiol benzoate. The response of the normal rats was slight, and the testosterone propionate-treated rats were the least affected. Adrenal, pituitary, and ovarian weights were found to be affected by the neonatal hormone treatments. Vaginal patency was completely inhibited in the rats injected with testosterone propionate. It is concluded that rats neonatally sterilized with steroids are much less suitable than ovariectomized animals for oestrogen assays.

Antioestrogen inhibition of oestradiol-induced alterations in hypothalamic noradrenaline turnover

1985 ◽  
Vol 106 (1) ◽  
pp. 37-42 ◽  
Author(s):  
C. Hiemke ◽  
B. Poetz ◽  
R. Ghraf
Keyword(s):  
Brain Area ◽  
Serum Levels ◽  
Ovariectomized Rats ◽  
Noradrenaline Turnover ◽  
Stimulatory Action ◽  
Enhanced Sensitivity ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Secretory System

ABSTRACT Long-term (4–6 weeks) ovariectomized rats were injected with either oestradiol benzoate (OB; 20 μg s.c.) or monohydroxytamoxifen (MTAM; 0·2 mg i.p.) plus OB. Oestradiol benzoate was administered at 12.00 h on day 0 and MTAM was given immediately before OB, followed by further injections twice daily to maintain sufficiently high antioestrogen levels. When given alone, OB reduced the serum levels of LH during the morning (08.00–09.00 h) and afternoon (17.30–18.30 h) hours of day 3 after priming. The feedback actions of OB on LH release were accompanied by time-dependent alterations of noradrenaline turnover in the preoptic–anterior hypothalamic brain area (POAH). On day 3 after priming the noradrenaline turnover rate was reduced in the morning and increased in the afternoon. The increase correlated with an enhanced sensitivity of the LH secretory system to progesterone. The antioestrogen MTAM blocked the OB-induced sensitization of LH release to the stimulatory action of progesterone and interfered with the stimulatory long-term effect of oestradiol on hypothalamic noradrenaline turnover. The data strongly support the view that the oestrogen-induced afternoon increase of noradrenaline turnover in the POAH represents a pre-requisite for the induction of LH surges. The stimulatory effect of oestradiol on hypothalamic noradrenaline turnover seems to be mediated by a classical oestrogen receptor mechanism. J. Endocr. (1985) 106, 37–42

Gastric inhibitory polypeptide release from a tumor-derived cell line

1995 ◽  
Vol 269 (2) ◽  
pp. E316-E322 ◽  
Author(s):  
T. J. Kieffer ◽  
Z. Huang ◽  
C. H. McIntosh ◽  
A. M. Buchan ◽  
J. C. Brown ◽  
...  
Keyword(s):  
Cell Line ◽  
High Performance ◽  
Neutralizing Antibody ◽  
Gastric Inhibitory Polypeptide ◽  
Total Cell ◽  
Controlled Environment ◽  
Intestinal Tumors ◽  
Cell Content ◽  
Basal Release ◽  
A Cell

A cell line derived from intestinal tumors of transgenic mice (STC-1) was subcloned to produce a stable line with approximately 30% immunoreactive gastric inhibitory polypeptide (irGIP)-containing cells (STC 6-14). High-performance liquid chromatography (HPLC) of STC 6-14 extracts indicated that the tumor cell-derived irGIP had the same retention time as synthetic porcine GIP-(1-42) (pGIP). Approximately 30% of the cells also contained immunoreactive somatostatin (irSS), which eluted as a single peak on HPLC, corresponding with SS-(1-14). On average, each well of extracted cells (5.0 x 10(5) cultured 4 days) contained 33.3 +/- 1.4 ng irGIP and 18.4 +/- 1.5 ng irSS. Basal release of irGIP in the presence of 5 mM glucose was 733 +/- 58 pg.ml cells-1.2h-1 (2.20 +/- 0.17% of total cell content; TCC) and doubled at 20 mM glucose (4.20 +/- 0.42% TCC). The response to glucose was augmented by addition of a SS neutralizing antibody (SOMA-10) and suppressed by 10 nM SS. Basal release of irSS in 5 mM glucose was 377 +/- 35 pg.ml cells-1.2h-1 (2.05 +/- 0.19% TCC) and was increased by glucose (> or = 15 mM) and the addition of pGIP (> or = 1 nM). The STC 6-14 cell line represents a model to study the synthesis, storage, and release of GIP and SS in a controlled environment.

RESTORATION BY OESTRADIOL BENZOATE OF A NEURAL AND HORMONAL RHYTHM IN THE OVARIECTOMIZED RAT

1975 ◽  
Vol 64 (1) ◽  
pp. 27-35 ◽  
Author(s):  
F. R. BURNET ◽  
P. C. B. MACKINNON
Keyword(s):  
Single Injection ◽  
Time Of Day ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Functional Link ◽  
Initial Injection ◽  
Oestradiol Benzoate ◽  
Before And After ◽  
Lh Release ◽  
The Brain

SUMMARY The rate of [35S]methionine incorporation into protein in discrete cerebral areas was measured before and after the administration of oestradiol benzoate (OB) to chronically ovariectomized rats. The circadian rhythm of incorporation which is normally seen in the intact cyclic female rat was deleted by ovariectomy. A daily rhythm of incorporation reappeared, however, in all the brain areas studied 30 h after a single injection of OB (20 μg), and was still present 12 days later. The release of luteinizing hormone (LH) after administration of 20 μg OB was measured in chronically ovariectomized animals and was found to be biphasic. High levels of LH after ovariectomy were initially reduced by negative feedback, but this phase was followed 52 h later by a facilitation of LH release between 15.00 and 18.00 h. The facilitation of LH release at this time of day was still detectable 12 days after the initial injection. The evidence for a functional link between the rhythm of neural activity which is reflected by [35S]methionine incorporation, and the ability to 'time' the facilitation of LH release is discussed.

Interaction between 16α,17α-cyclopropane progesterone and progesterone receptors in rat uterus

1998 ◽  
Vol 125 (5) ◽  
pp. 471-473 ◽  
Author(s):  
A. N. Smirnov ◽  
E. V. Pokrovskaya ◽  
V. P. Shevchenko ◽  
I. S. Levina ◽  
A. V. Kamernitskii
Keyword(s):  
Progesterone Receptors ◽  
Rat Uterus
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