Comparative response to oestradiol in the synthesis of the progesterone receptor in the maternal and foetal uterus of guinea pig and rabbit at the end of gestation

1981 ◽  
Vol 98 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Francoise Laure ◽  
Jorge Raul Pasqualini
Keyword(s):  
Progesterone Receptor ◽  
Guinea Pig ◽  
Binding Sites ◽  
Saline Solution ◽  
Specific Binding ◽  
Cytosol Fraction ◽  
Specific Binding Sites ◽  
Comparative Response ◽  
Injection Control ◽  
Stimulation Of

Abstract. In the present paper the stimulatory effect of oestradiol on the progesterone receptor (PR) in two species: rabbit and guinea pig, is studied in both the maternal and foetal uterine tissues. Oestradiol (1 mg/kg/day) in saline solution was injected sc into the maternal compartment of pregnant guinea pig and rabbit at the end of gestation for 3 consecutive days and the PR evaluated 24 h after the last injection; control animals received the vehicle alone. In the maternal uterus the number of specific binding sites in the cytosol fraction for the synthetic progestagen R-5020 (17α,21-dimethyl-19-nor-pregna-4,9-diene-3,20-dione) in the non-treated animals was, for the rabbit 117 ± 25 (sd) fmol/mg protein and for the guinea pig 325 ± 62 (sd) fmol/mg protein. In the treated animals a stimulation is observed of 2.5–3 times, 315 ± 85 (sd) fmol/mg protein for the maternal uterus of rabbit and 865 ± 100 (sd) fmol/mg protein for the maternal uterus of guinea pig. In the foetal uterus it is a very different picture, while in the foetal uterus of guinea pig a great stimulatory effect is observed on the PR; from 267 ± 53 (sd) fmol/mg protein in the nontreated animals to 1984 ± 357 (sd) in the oestradiolprimed animals; in the foetal uterus of rabbit very little or no PR is detectable in the non-treated animals while in the treated animals with the same or 1/20 of the dose of oestradiol for only 1 day, the death of the foetus was provoked. In summary, the effect of oestradiol on the stimulation of PR in maternal uterine tissue is similar in these two species. In the foetal uterus of guinea pig the response to the action of oestradiol on the PR is very significant but this hormone is of great toxicity for the rabbit foetus. It is concluded that the oestradiol response of the foetus is related to the maturity of the foetus.

Effect of heavy metals and lanthanum on sugar transport in isolated guinea pig left atria

1980 ◽  
Vol 58 (10) ◽  
pp. 1184-1188 ◽  
Author(s):  
I. Bihler ◽  
L. E. Hoeschen ◽  
P. C. Sawh
Keyword(s):  
Heavy Metals ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Sugar Transport ◽  
Free Medium ◽  
Specific Binding Sites ◽  
Stimulation Of

The effect of heavy metals on sugar transport in fully resting guinea pig left atria was studied by measuring the tissue–medium distribution of 3-methylglucose. Basal sugar transport was increased significantly by all heavy metals tested (Co2+, Ni2+, Zn2+, Mn2+ (2 mM)) and by La3+ (0.05 mM) but 1 mM La3+ had no effect. The stimulation of sugar transport by insulin, hyperosmolarity, K+-free medium, or 10−5 M ouabain was strongly antagonized by Ni2+, Zn2+, and La3+ but was unaffected by Co2+ and Mn2+. The heavy metals did not affect intracellular Na2+ and K+, whether in the basal state or when the Na+ pump was depressed by ouabain or K+-free medium. The data suggest that Ca2+ antagonistic ions may affect sugar transport both by inhibiting Ca2+ influx and by competing with Ca2+ for specific binding sites presumably involved in the regulation of sugar transport.

Regulation of angiotensin II binding sites in neuronal cultures by catecholamines

1989 ◽  
Vol 257 (4) ◽  
pp. C706-C713 ◽  
Author(s):  
L. M. Myers ◽  
C. Sumners
Keyword(s):  
Angiotensin Ii ◽  
Binding Sites ◽  
Phorbol Esters ◽  
De Novo ◽  
Specific Binding ◽  
Physiological Mechanism ◽  
Neuronal Cultures ◽  
Ang Ii ◽  
Specific Binding Sites ◽  
Stimulation Of

Previous studies determined that direct activation of protein kinase C (PKC) with phorbol esters increases the number of angiotensin II (ANG II)-specific binding sites in neuronal cultures prepared from the hypothalamus and brain stem of 1-day-old rats. In the physiological situation, PKC is activated by diacylglycerol, which can be produced by multiple pathways, such as stimulation of inositol phospholipid (IP) hydrolysis, phosphatidylcholine hydrolysis, or by de novo synthesis. In the present study we have examined whether stimulation of IP hydrolysis, and presumably activation of PKC, can mimic the actions of phorbol esters on ANG II-specific binding. We have incubated neuronal cultures with agents that increase IP hydrolysis and have determined the effects on ANG II-specific binding. Incubation of neuronal cultures with norepinephrine (NE) at concentrations (greater than 5 microM) and for times (15-60 min) that cause large increases in IP hydrolysis caused increases in the number of ANG II-specific binding sites, mimicking the actions of phorbol esters. The return of IP hydrolysis to control values was associated with a return of ANG II-specific binding to control levels. The upregulatory action of NE was abolished by prazosin, demonstrating the involvement of alpha 1-adrenergic receptors. In addition, this effect was blunted by the PKC antagonist H 7, suggesting PKC involvement in the response. Thus we have determined a potential physiological mechanism by which stimulation of IP hydrolysis by NE, and possible subsequent activation of PKC, leads to upregulation of ANG II-specific binding sites in neuronal cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Characterization of specific binding sites of 3H-labelled platelet-activating factor ([3H]PAF) and a new antagonist, [3H]SR 27417, on guinea-pig tracheal epithelial cells

1992 ◽  
Vol 284 (1) ◽  
pp. 201-206 ◽  
Author(s):  
J M Herbert
Keyword(s):  
Epithelial Cells ◽  
Guinea Pig ◽  
Binding Sites ◽  
Specific Binding ◽  
Platelet Activating Factor ◽  
Tracheal Epithelial Cells ◽  
Specific Binding Sites ◽  
Paf Receptor ◽  
Tracheal Epithelial ◽  
Paf Receptor Antagonist

Binding of 3H-labelled platelet-activating factor ([3H]PAF) to guinea-pig tracheal epithelial cells was time-dependent, reversible and saturable. Scatchard analysis of the saturation-binding data indicated that [3H]PAF bound to one class of specific binding sites with high affinity (KD = 4.3 +/- 0.03 nM; Bmax. = 0.172 +/- 0.02 fmol/10(5) cells; n = 3). Unlabelled PAF competitively and selectively inhibited the specific binding of [3H]PAF with 50% inhibition at 4.8 +/- 0.07 nM (n = 3). SR 27417, the first member of a newly developed PAF antagonist series, competitively displaced [3H]PAF from its binding sites on guinea-pig tracheal epithelial cells with a Ki of 100 +/- 3 pM (n = 3). Studies carried out in parallel demonstrated that SR 27417 was 40 times more potent than C16-PAF itself and more than 100-fold as active as the best synthetic PAF-receptor antagonist yet described. [3H]SR 27417 displayed high-affinity, specific, reversible as well as saturable binding to a single class of binding sites on tracheal epithelial cells (KD = 94 +/- 7 pM; Bmax. = 0.181 +/- 0.04 fmol/10(5) cells; n = 3). C16-PAF, lyso-PAF, enantio-PAF, SR 27417 and other PAF-receptor antagonists had Ki values which were nearly identical for both [3H]PAF and [3H]SR 27417, demonstrating that in guinea-pig tracheal epithelial cells they have the same binding sites. In conclusion, these data suggest that tracheal epithelial cells contain PAF-specific receptors and indicate that SR 27417 is an extremely potent PAF-receptor antagonist, as well as being a suitable radioligand for labelling PAF receptors on intact cells.

Autoradiographical localization of oxytocin-binding sites in the guinea-pig ovary at different stages of the oestrous cycle

1991 ◽  
Vol 131 (3) ◽  
pp. 421-NP ◽  
Author(s):  
L. Zhang ◽  
J. J. Dreifuss ◽  
M. Dubois-Dauphin ◽  
E. Tribollet
Keyword(s):  
Guinea Pig ◽  
Binding Sites ◽  
Ovarian Function ◽  
Specific Binding ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Specific Binding Sites ◽  
Ovarian Stroma ◽  
Theca Externa ◽  
Theca Interna

ABSTRACT The discovery that oxytocin is synthesized and stored in corpora lutea of ruminants has fostered a renewed interest in the possible roles of oxytocin in ovarian function. In the present study we describe the distribution of binding sites for oxytocin in the guinea-pig ovary. Sections were reacted with a radioiodinated oxytocin antagonist (125I-labelled OTA) to yield autoradiograms on film. Specific binding sites for oxytocin were defined as those which bound 0·05 nmol 125I-labelled OTA/l and where 1 μmol non-radioactive oxytocin/1 displaced the radioactivity. 125I-Labelled OTA consistently labelled the ovarian stroma and the theca interna, but not the corpora lutea, the granulosa cells or the theca externa. The amount of 125I-labelled OTA bound to ovarian stroma and theca interna was high in animals killed during dioestrus, and low during and shortly after oestrus. These data suggest that the binding sites are regulated by steroid hormone levels and that in the guinea-pig ovary oxytocin could exert a role in follicular steroidogenesis, maturation or ovulation rather than in luteal function. Oxytocin-binding sites were also shown in the uterus but their numbers varied only slightly during the cycle. Journal of Endocrinology (1991) 131, 421–426

Effects of seven different oestrogen sulphates on uterine growth and on progesterone receptor in the foetal uterus of guinea pig after administration to the mother

1982 ◽  
Vol 101 (4) ◽  
pp. 630-635 ◽  
Author(s):  
J. R. Pasqualini ◽  
A. Lanzone ◽  
A. Tahri-Joutei ◽  
B. L. Nguyen
Keyword(s):  
Progesterone Receptor ◽  
Guinea Pig ◽  
Specific Binding ◽  
Biological Effects ◽  
Biological Response ◽  
The Other ◽  
Specific Binding Sites ◽  
Other Hand ◽  
Uterine Growth ◽  
Two Parameters

Abstract. The biological effect of seven different oestrogen sulphates: oestrone-3-sulphate (E1-3-S), oestradiol-3-sulphate (E2-3-S), oestradiol-17-sulphate (E2-17-S), oestradiol-3,17-disulphate (E23,17-DS), oestriol-3-sulphate (E3-3-S), oestriol-17-sulphate (E3-17-S), oestriol-3,16,17-trisulphate (E3-3,16,17-TS), was studied in the foetal uterus of guinea pig (55–65 days of gestation) after sc administration for 3 consecutive days of each sulphate to the mother. On day 4, two response parameters were investigated, the uterotrophic effect and the action on the progesterone receptor. The monosulphates at the C3 position of the oestrogens (E1-3-S, E2-3-S and E3-3-S) provoked an increase in uterine weight of 1.9–2.4 times in relation to the non-treated animals. These oestrogen sulphates also very significantly stimulated the number of progesterone specific binding sites, 7–10 times in relation to the non-treated animals. On the other hand, when the sulphate was at C17 of the oestrogens (E2-17-S, E3-17-S, E2-3, 17-DS, E3-3,16,17-TS), very little or no effect on the foetal uterus was observed on the two parameters studied. It is concluded that oestrogen (oestrone, oestradiol, oestriol) sulphates in position C3 can be involved in the biological response to the hormone and it is suggested that the effect is carried out after the hydrolysis of the sulphate. On the other hand, sulphates in C17 are not hydrolysed and no significant biological effects were observed in the uterine growth or in the progesterone receptor.

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