scholarly journals The Endometrium Contributes to the Differential Contractile Response to Oxytocin of Uterine Tissue from Virgin and Proven Breeder Non‐pregnant Rats

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Korie Sondgeroth ◽  
Amber Boening ◽  
Maura Porta
Keyword(s):  
Contractile Response ◽  
Uterine Tissue ◽  
Pregnant Rats

METABOLISM OF 20β-HYDROXY-4-PREGNEN-3-ONE IN UTERINE TISSUE OF NON-PREGNANT RATS IN VITRO

1976 ◽  
Vol 83 (3) ◽  
pp. 604-620 ◽  
Author(s):  
B. P. Lisboa ◽  
M. Holtermann
Keyword(s):  
Biological Activity ◽  
Adult Female ◽  
Female Rats ◽  
Uterine Tissue ◽  
Rat Uterus ◽  
Adult Rats ◽  
Pregnant Rats ◽  
Progesterone Metabolites ◽  
Ovariectomized Adult Rats

ABSTRACT In vitro experiments carried out with uterus preparations of ovariectomized adult rats indicate the presence in this tissue of a 20β-hydroxysteroid-oxidoreductase which catalyzes the conversion of 20β-hydroxy-4-pregnen-3-one to progesterone. Since a hepatic 20β-hydroxysteroid-oxidoreductase is absent in adult female rats, the myometrial enzyme can be responsible for the biological activity of 20β-hydroxy-4-pregnen-3-one in these animals. Besides progesterone five metabolites were isolated and identified after incubation of [4-14C]20β-hydroxy-4-pregnen-3-one with uterine tissue: 20β-hydroxy-5α-pregnan-3-one, 20β-hydroxy-5β-pregnan-3-one, 5α-pregnane-3α,20β-diol, 4-pregnene-3α,20β-diol and 4-pregnene-3β,20β-diol. The conversion of 20β-hydroxy-4-pregnen-3-one to progesterone permits us to regard all five steroids isolated as progesterone metabolites in the rat uterus. 20β-hydroxy-5β-pregnan-3-one is the first C21-metabolite with a 5β(H)-configuration isolated in the rat uterus, which indicates the presence of 5β-reductase in this tissue.

METABOLISM OF PROGESTERONE IN UTERINE TISSUE OF NON-PREGNANT RATS IN VITRO

1976 ◽  
Vol 83 (3) ◽  
pp. 583-603 ◽  
Author(s):  
B. P. Lisboa ◽  
M. Holtermann
Keyword(s):  
Quantitative Difference ◽  
Total Activity ◽  
Allylic Alcohols ◽  
Uterine Tissue ◽  
Oxidoreductase Activity ◽  
Pregnant Rats ◽  
Progesterone Metabolites ◽  
Influence Of Substrate ◽  
First Time

ABSTRACT The metabolism of labelled progesterone was studied in vitro in uterine tissue of non-pregnant rats with particular emphasis on the influence of substrate concentration. Neither a qualitative nor quantitative difference was found for a steroid tissue ratio between 15 × 10−6 and 4.2 × 10−9 to 1 g (substrate amounts between 57.73 and 0.02 nmol); with both concentrations 42 to 44 per cent of progesterone was metabolized to about 35 per cent monohydroxymonoketonic steroids and 4–6 per cent dihydroxylated C21O2-compounds. In both sets of incubations we have isolated and identified the following steroids: 3α-hydroxy-5α-pregnan-20-one, 3β-hydroxy-4-pregnen-20-one, 3α-hydroxy-4-pregnen-20-one, 20α-hydroxy-4-pregnen-3-one, 5α-pregnane-3α,20α-diol and 4-pregnene-3α,20α-diol. The most abundant metabolite formed in these incubations was 3α-hydroxy-4-pregnen-20-one -which corresponds to about 30 per cent of the total activity recovered. It is the first time that the presence of 20α-hydroxysteroid-oxidoreductase activity is definitely established in this type of tissue. The identification of three allylic alcohols as progesterone metabolites in the rat uterus confirms that Δ4-3-hydroxysteroids are important intermediates in the in vitro uterine metabolism of steroids.

Progesterone metabolism by uterine tissue of pregnant rats

Steroids ◽  
1972 ◽  
Vol 19 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Phillenore D. Howard ◽  
Walter G. Wiest
Keyword(s):  
Uterine Tissue ◽  
Pregnant Rats ◽  
Progesterone Metabolism

scholarly journals The effects of the aromatase inhibitor fadrozole hydrochloride on fetuses and uteri in late pregnant rats

2004 ◽  
Vol 180 (2) ◽  
pp. 337-345 ◽  
Author(s):  
H Tamada ◽  
Y Shimizu ◽  
T Inaba ◽  
N Kawate ◽  
T Sawada
Keyword(s):  
Physical Properties ◽  
Aromatase Inhibitor ◽  
Mrna Expression ◽  
Lysyl Oxidase ◽  
Late Pregnancy ◽  
Estrogen Deficiency ◽  
Uterine Tissue ◽  
Pregnant Rats ◽  
Toxicological Effects ◽  
Matrix Metalloproteinase 1

It is well known that progesterone and estrogen are essential hormones for maintaining pregnancy in most mammals. Some specific roles of progesterone for the maintenance of pregnancy have been clarified, but the role of estrogen is not well known. This study examines the effects of the aromatase inhibitor, fadrozole hydrochloride (Fad), on fetuses, uterine physical properties and the mRNA expression of the uterine enzymes that are related to collagen metabolism during late pregnancy in rats. Continuous s.c. infusion with 300 micro g/day Fad from day 14 of pregnancy (day 1=the day of sperm detection) reduced the concentration of plasma estradiol-17beta (E(2)), and did not change that of plasma progesterone, compared with controls. The treatment increased the intrauterine pressure and reduced the size and compliance of the uterine tissue framework. It also caused injuries (hematomata on the extremities) in about one-quarter of fetuses by day 20. The collagen content of the uterine ampullae was not changed by the treatment. Uterine mRNA expressions of matrix metalloproteinase-1 (MMP-1), which degrades collagens, and of lysyl oxidase (LO), which is necessary for the formation of intra- and inter-molecular cross-links of collagen, were examined by quantitative RT-PCR. The treatment with Fad had no effect on the expression of MMP-1 mRNA and increased that of LO mRNA. Daily s.c. injection with 0.2 micro g E(2) restored the changes in uterine physical properties and the mRNA expression of LO caused by the Fad treatment, and prevented fetal injury, indicating that the influences of Fad treatment are due to estrogen deficiency but not to toxicological effects of Fad. These results imply that estrogen deficiency during late pregnancy in rats obstructs development of the uterine tissue framework so as to cause fetal injury. It is possible that an increase in the uterine expression of LO gene may be involved in this obstruction.

scholarly journals Effects of different vasopressors on the contraction of the superior mesenteric artery and uterine artery in rats during late pregnancy

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tingting Wang ◽  
Limei Liao ◽  
Xiaohui Tang ◽  
Bin Li ◽  
Shaoqiang Huang
Keyword(s):  
Caesarean Section ◽  
Blood Vessels ◽  
Mesenteric Artery ◽  
Uterine Artery ◽  
Contractile Response ◽  
Mesenteric Arteries ◽  
Response Curves ◽  
Pregnant Rats ◽  
Neuraxial Anaesthesia ◽  
Significant Difference

Abstract Background Hypotension after neuraxial anaesthesia is one of the most common complications during caesarean section. Vasopressors are the most effective method to improve hypotension, but which of these drugs is best for caesarean section is not clear. We assessed the effects of vasopressors on the contractile response of uterine arteries and superior mesenteric arteries in pregnant rats to identify a drug that increases the blood pressure of the systemic circulation while minimally affecting the uterine and placental circulation. Methods Isolated ring segments from the uterine and superior mesenteric arteries of pregnant rats were mounted in organ baths, and the contractile responses to several vasopressor agents were studied. Concentration-response curves for norepinephrine, phenylephrine, metaraminol and vasopressin were constructed. Results The contractile response of the mesenteric artery to norepinephrine, as measured by the pEC50 of the drug, was stronger than the uterine artery (5.617 ± 0.11 vs. 4.493 ± 1.35, p = 0.009), and the contractile response of the uterine artery to metaraminol was stronger than the mesenteric artery (pEC50: 5.084 ± 0.17 vs. 4.92 ± 0.10, p = 0.007). There was no statistically significant difference in the pEC50 of phenylephrine or vasopressin between the two blood vessels. Conclusions In vitro experiments showed that norepinephrine contracts peripheral blood vessels more strongly and had the least effect on uterine artery contraction. These findings support the use of norepinephrine in mothers between the time of neuraxial anaesthesia and the delivery of the foetus.

scholarly journals Effects of different vasopressors on the contraction of the superior mesenteric artery and uterine artery in rats during late pregnancy

2021 ◽  
Author(s):  
Tingting Wang ◽  
Limei Liao ◽  
Xiaohui Tang ◽  
Bin Li ◽  
Shaoqiang Huang
Keyword(s):  
Caesarean Section ◽  
Mesenteric Artery ◽  
Uterine Artery ◽  
Contractile Response ◽  
Mesenteric Arteries ◽  
Response Curves ◽  
Pregnant Rats ◽  
Neuraxial Anaesthesia ◽  
Significant Difference

Abstract Background：Hypotension after neuraxial anaesthesia is one of the most common complications during caesarean section. Vasopressors are generally agreed to be the most effective way to improve hypotension, but it is unclear which of these drugs is best for caesarean section. We assessed the effects of vasopressors on the contractile response of uterine arteries and superior mesenteric arteries in pregnant rats, with the goal of identifying a drug that raises the blood pressure of the systemic circulation while minimally affecting the uterine and placental circulation. Methods： Isolated ring segments from the uterine and superior mesenteric arteries of pregnant rats were mounted in organ baths, and their contractile responses to several vasopressor agents were studied. Concentration-response curves for norepinephrine, phenylephrine, metaraminol and vasopressin were constructed. Results：The experimental results showed that the contractile response of the mesenteric artery to norepinephrine, as measured by the pEC50 of the drug, was stronger than that of the uterine artery (5.617 ± 0.11 vs. 4.493 ± 1.35, p=0.009), and the contractile response of the uterine artery to metaraminol was stronger than that of the mesenteric artery (pEC50: 5.084±0.17 vs 4.92±0.10, p=0.007). There was no statistically significant difference in the pEC50 of phenylephrine or vasopressin between the two blood vessels. Conclusion： In vitro experiments show that compared with phenylephrine, metaraminol , vasopressin, norepinephrine can contract peripheral blood vessel more strongly, while having the least effect on the contraction of uterine artery. These findings provide some support for the use of norepinephrine in mothers between the time of neuraxial anaesthesia and the delivery of the foetus.

scholarly journals Up-regulation of oxytocin receptors in non-pregnant rat myometrium by isoproterenol: effects of steroids

1999 ◽  
Vol 161 (3) ◽  
pp. 403-411 ◽  
Author(s):  
T Engstrom ◽  
P Bratholm ◽  
NJ Christensen ◽  
H Vilhardt
Keyword(s):  
Gene Expression ◽  
Plasma Membranes ◽  
Contractile Response ◽  
Oxytocin Receptor ◽  
Gonadal Steroids ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Oxytocin Receptors ◽  
Important Regulator ◽  
Isoproterenol Infusion

The objective of the present study was to further elucidate our previous observation that beta2-adrenoceptor activation induces oxytocin receptor (OTR) expression in rat myometrium. We wanted to investigate whether the mechanism behind this effect was under the influence of gonadal steroids. Ovariectomized non-pregnant rats were treated with estrogen, progesterone or a combination of both for 3 days. Some rats were concomitantly treated with isoproterenol. Estrogen treatment increased both OTR mRNA production and maximal binding of [3H]-oxytocin to isolated myometrial plasma membranes, but it did not affect contractility of isolated uterine strips challenged with oxytocin. When the estrogen regimen was combined with isoproterenol treatment, an augmented maximal contractile response (Emax) to oxytocin was observed although no further increase in OTR mRNA and binding was seen. Progesterone treatment did not in itself alter OTR mRNA, OTR binding or Emax. However, OTRs were induced at the level of gene expression when progesterone was supplemented with isoproterenol infusion. Finally, progesterone suppressed the effect of estrogen on OTR mRNA production and binding when the two compounds were administered together. However, when isoproterenol treatment was added this effect was abolished and Emax was enhanced more than that seen following treatment with estrogen alone. These data suggest that beta2-adrenoceptor activation represents an important regulator of OTR expression/function in estrogen- and progesterone-dominated rat myometrium.

PROGESTERONE IN THE UTERUS

1974 ◽  
Vol 77 (1) ◽  
pp. 160-170 ◽  
Author(s):  
D. Egert ◽  
H. Maass
Keyword(s):  
Extracellular Fluid ◽  
Uterine Tissue ◽  
Rat Uterus ◽  
Pregnant Rats ◽  
Pregnant Rat

ABSTRACT Radio-metabolites of progesterone and progesterone itself were found in the uteri of intact pregnant rats 20 min after injection of [1,2-3H]progesterone. However, after evisceration and removal of the foeto-placental unit, and following injection of the labelled steroid, the progesterone content in the extract from the pregnant rat uterus markedly increased while the metabolite levels correspondingly decreased. An analogous change was observed in the plasma. Thus it appears probable that progesterone is not metabolized in the uterus of pregnant rats, and that metabolites found in this tissue originate predominantly in the foetoplacental system and appear in the plasma and extracellular fluid present in the uterine tissue.

Modification of Pineal Ultrastructure by Exogenous Hormones

1967 ◽  
Vol 25 ◽  
pp. 170-171
Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
List Type ◽  
Type Number ◽  
Pregnant Rats ◽  
Gonadal Atrophy ◽  
Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

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