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PubMed1999

Fatty-acid amide hydrolase is expressed in the mouse uterus and embryo during the periimplantation period.

Arachidonoylethanolamide (anandamide) is an endogenous ligand for cannabinoid receptors. We demonstrated previously that the periimplantation mouse uterus has high levels of anandamide and can synthesize and hydrolyse anandamide. In the present investigation, we examined the expression of the recently identified fatty-acid amide hydrolase (FAAH) gene, which is involved in hydrolyzing anandamide to arachidonic acid and ethanolamine, in the periimplantation mouse embryo and uterus. As previously reported, Northern blot hybridization detected a transcript of approximately 2.5 kilobases of FAAH mRNA in whole uterine poly(A)+ RNA samples. The levels of this mRNA were higher in the liver and brain than in the uterus. In the uterus, higher accumulation of FAAH mRNA occurred on Days 1-4 followed by declines on later days (Days 5-8) of pregnancy. In situ hybridization detected this mRNA primarily in uterine luminal and glandular epithelial cells on Days 1-4 of pregnancy. With the progression of implantation (Days 5-8), accumulation of this mRNA was retained in the luminal and glandular epithelia. In addition, implanting blastocysts showed accumulation of this mRNA. FAAH mRNA accumulation was absent or minimal in the myometrium during this period. Western blotting detected an approximately 60-kDa protein in uterine membrane preparations. In preimplantation embryos, FAAH mRNA was present in one-cell and two-cell embryos but was absent in embryos at the eight-cell/morula stage. However, this mRNA was again detected in Day 4 blastocysts. The presence of FAAH mRNA in one- and two-cell embryos reflects accumulation of maternal message, while its presence in blastocysts reflects embryonic gene activation. Collectively, our present and previous results provide evidence that FAAH is expressed in the mouse uterus and embryo during early pregnancy to modulate local levels of anandamide that could be important for embryo development and implantation.

Amidohydrolases↗
PubMed1999

A comparative study of estrogen receptors alpha and beta in the rat uterus.

The uterus is an important target organ for steroid hormones. The effects of these hormones are mediated via specific receptors. The aim of this study was to compare the expression, distribution, and regulation of estrogen receptor (ER) alpha and beta in the rat uterus in order to establish possible different biological roles for the two receptor forms. Ovariectomized rats were treated with either estradiol (E(2)), progesterone (P(4)), or combinations of these for 24 or 48 h. The mRNA levels were measured by solution hybridization. Distribution of the mRNAs and receptor proteins was detected by in situ hybridization and immunohistochemistry. The results showed that ERalpha is the dominating subtype in the rat uterus. E(2) seemed to increase the ERalpha mRNA level in the glandular and luminal epithelium, but it caused a decrease of the immunostaining intensity in the glandular epithelium. P(4) reduced ERalpha expression in luminal epithelium whereas no effect was seen in the glandular epithelium. E(2) or P(4) did not alter the expression of ERbeta, on either the mRNA or protein level. In conclusion, the distribution and regulation of ERalpha and ERbeta differ in the different compartments of the rat uterus. The complex uterine responses to E(2) and P(4) are directly or indirectly mediated by differential cell-specific expression of their receptors. The low expression in the uterus and the limited regulation by gonadal steroids in this study suggest that ERbeta probably plays a minor role in the regulation of uterine physiology.

Animals↗
PubMed2002

Differential expression of microsomal prostaglandin e synthase at implantation sites and in decidual cells of mouse uterus.

Prostaglandin E(2) (PGE(2)) is considered important for blastocyst spacing, implantation, and decidualization in the rodent uterus. PGE synthase (PGES) catalyzes the isomerization of PGH(2) to PGE(2). There are two isoforms of PGES, microsomal PGES (mPGES) and cytosolic PGES (cPGES). However, the expression and regulation of mPGES in the mammalian uterus during early pregnancy are still unknown. The aim of this study was to investigate the differential expression of mPGES in mouse uterus during early pregnancy and its regulation under different conditions by in situ hybridization and immunohistochemistry. Microsomal PGES expression in the preimplantation mouse embryos was also performed by reverse transcription polymerase chain reaction (RT-PCR). Expression of mPGES mRNA and protein was at a basal level in the luminal epithelium from Day 1 to Day 4 of pregnancy. However, mPGES mRNA and protein were highly expressed in the stroma immediately surrounding the blastocyst but not in the luminal epithelium on Day 5 of pregnancy. Microsomal PGES mRNA and protein were not detected in the pseudopregnant uterus from Day 1 to Day 5. During delayed implantation, mPGES mRNA and protein were also not detected in the uterus. Once delayed implantation was terminated by estrogen treatment and embryo implantation initiated, both mPGES mRNA and protein were induced to express in the stroma immediately surrounding the blastocyst, which was similar to the expression pattern on Day 5 of pregnancy. From Day 6 to Day 8 of pregnancy, the signals for mPGES mRNA and protein were strongly detected in the decidualized cells. Microsomal PGES mRNA and protein were also highly expressed in the artificially decidualized cells but not in the control horn. Microsomal PGES mRNA was detected in the oocytes and all the stages of preimplantation embryos. The strong mPGES expression in the implantation site and decidual cells suggests that mPGES might play an important role during implantation and more importantly in decidualization.

Animals↗
PubMed2002

Involvement of androgen receptor in 17beta-estradiol-induced cell proliferation in rat uterus.

Although it is known that, in the uterus, estrogen receptor alpha (ERalpha) is involved in proliferation and progesterone receptor in differentiation, the role of the two other gonadal-hormone receptors expressed in the uterus, androgen receptor (AR) and estrogen receptor beta (ERbeta), remains undefined. In this study, the involvement of AR in 17beta-estradiol (E(2))-induced cellular proliferation in the immature rat uterus was investigated. AR levels were low in the untreated immature uterus, but 24 h after treatment of rats with E(2), there was an increase in the levels of AR and of two androgen-regulated genes, IGF-I and Crisp (cysteine-rich secretory protein). As expected, E(2) induced proliferation of luminal epithelial cells. These actions of E(2) were all blocked by both the antiestrogen tamoxifen and the antiandrogen flutamide. The E(2)-induced AR was found by immunohistochemistry to be localized exclusively in the stroma, mainly in the myometrium, where it colocalized with ERalpha but not with ERbeta. ERbeta, detected with two different ERbeta-specific antibodies, was expressed in both stromal and epithelial cells either alone or together with ERalpha. Treatment with E(2) caused down-regulation of ERalpha and ERbeta in the epithelium. The data suggest that, in E(2)-induced epithelial cell proliferation, ERalpha induces stromal AR and AR amplifies the ERalpha signal by induction of IGF-I. Because AR is never expressed in cells with ERbeta, it is unlikely that ERbeta signaling is involved in this pathway. These results indicate an important role for AR in proliferation of the uterus, where estrogen and androgen do not represent separate pathways but are sequential steps in one pathway.

Androgen Antagonists↗
PubMed2000

The effect of nitroglycerin on the gravid uterus in sheep and rabbits.

UNLABELLED: Clinical reports suggest that nitroglycerin (TNG) has an effect on the uterus that is detected by the obstetrician on palpation, but not obvious by measurement of uterine pressure. This study was designed to compare the effects of TNG on uterine compliance and tension. We used three sets of experiments to evaluate the effect of TNG on the uterus. In vivo experiments were conducted on laboring ewes and rabbits 2 h postpartum to measure the effect of TNG on active uterine tension. An in vitro experiment was also conducted by using isolated uterine strips from term pregnant rabbits to evaluate the effect of TNG on uterine compliance. TNG had no discernible effect on uterine intracavitary pressure or frequency of contraction in either laboring ewes or postpartum rabbits at doses that were sufficient to reduce the mean arterial pressure. TNG did, however, increase the compliance of uterine tissue from rabbits at term, whereas S-nitroso-N-acetylpenicillamine failed to produce a similar effect. Thus, the perceived relaxant effects of TNG may be caused by an increase in uterine compliance, which may facilitate efforts by the obstetrician to manipulate the uterus. While the mechanism of action remains unclear, it appears to be independent of nitric oxide. IMPLICATIONS: The administration of nitroglycerin may have a relaxant effect on the uterus. These experiments were conducted to elucidate the effect of nitroglycerin on the peripartum uterus by measuring active tension and compliance.

Adrenergic beta-Agonists↗
PubMed2007

Human uterus retrieval from a multi-organ donor.

OBJECTIVE: To determine if a uterus can be retrieved for reproductive organ transplantation and to describe the surgical technique. METHODS: We participated in a local organ donor network retrieval team for over 6 months. Heart-beating, brain-dead multi-organ donors were identified through an existing donor network following routine protocols. RESULTS: After institutional review board and organ donor network approval of the uterus transplantation project, approximately 1,800 eligible organ donors were identified as required by legislation. Multi-organ procurement surgery took place in approximate 150 of these, with nine specifically consented for the uterus retrieval. Regularly performed multi-organ transplantation retrievals included the uterus without complications in eight donors. Pedicles used included the ovarian, uterine, or internal iliac vessels. After retrieval, serial histology sections throughout the period of cold ischemia, taken every 15-30 minutes, showed no signs of change over 12 hours of cold ischemia. CONCLUSION: The human uterus can be obtained from local organ donor networks using existing protocols. LEVEL OF EVIDENCE: III.

Adult↗
PubMed2006

The role of oestradiol in the uterine peristalsis in the perfused swine uterus.

This study was designed to examine the effects of oestradiol (E2) on sperm transport in the swine uterus. The bicornuate swine uterus is optimal for the study of the uterine transport and peristalsis because the influence of various factors can be examined on each uterine horn independently. Forty swine uteri (with or without ovarectomy) were perfused for a period of up to 7 h. Two different E2 concentrations (3 or 30 pg/ml) in the perfusion medium were administered for 30 min unilaterally. Through an intracervical catheter 1 ml of a high concentrated dextran blue solution was administered directly in the upper part of the cervix. After bilateral perfusion of the swine uterus with a bolus of 0.3 IU oxytocin the distribution of coloured particles was assessed macroscopically before and after incision of the uterine horns. Coloration was evaluated by two observers blinded to the site-specific administration of E2. In the 10 ovarectomized uteri with the 3 pg/ml E2 concentration a unilateral distribution towards the side of oestradiol administration was observed in six uteri, in four it was a bilateral distribution. In the 10 non-ovarectomized uteri with the 3 pg/ml E2 concentration a uni- and ipsilateral coloration was observed in five uteri, in five it was a bilateral distribution. In the 20 uteri with 30 pg/ml E2, a unilateral coloration of the uterus horns was observed in all uteri. Oestradiol is one of the main factors, which influences the direction of the sperm transport in a dose-dependent manner, in the perfused swine uterus.

Animals↗
PubMed1973

Some effects of histamine in the depolarized rat uterus.

1. The relaxant effect of histamine in the isolated rat uterus remained after the preparation was depolarized in a potassium Ringer.2. The effect was abolished by the calcium-chelating agent, ethyleneglycol bis-aminoethyl ether-tetraacetic acid (EGTA).3. Histamine caused relaxation during calcium-induced contractures in a depolarized uterus treated with EGTA, but did not produce relaxation during barium-induced contractures.4. While responses of a normally polarized rat uterus to acetylcholine were inhibited by histamine, those of a depolarized uterus were enhanced by histamine. The inhibitory effects of isoprenaline and papaverine on acetylcholine responses were maintained in depolarized preparations.5. Both the enhancing effect of histamine on responses to acetylcholine and the relaxation of calcium-induced contractures were abolished by burimamide, indicating that H(2)-receptors mediate the effects of histamine in the depolarized tissue.6. A reduction in the rate of exchange of calcium across the depolarized cell membrane was demonstrated with high concentrations of histamine.7. The results are consistent with the hypothesis that in the rat uterus, the stimulation of H(2)-receptors by histamine is accompanied by a reduction in calcium exchange across the membrane which may result in a decrease in the concentration of free intracellular calcium available to stimulate contraction of the myofilaments. Histamine may act by increasing the binding of calcium within the cell.

Acetates↗
PubMed1978

The action of bradykinin and oxytocin on the isolated whole uterus and myometrium of the rat in oestrus.

1. A technique is described for obtaining a myometrial preparation devoid of endometrium, from the uterus of the rat in oestrus. 2. Acetylcholine and prostaglandin F2alpha (PGF2alpha) produced concentration-effect curves with the same maximal tensions and slope on the whole uterus and myometrial preparations. Concentration-effect curves to bradykinin and oxytocin on the myometrial preparation were altered, resulting in a shift to the right and a decreased maximum response compared with those produced by the whole uterus. 3. Indomethacin produced greater antagonism of the responses of the whole uterus to bradykinin and oxytocin than to acetylcholine and PGF2alpha, whereas responses of the myometrium to all four agonists were similarly depressed. 4. Responses of the myometrial preparation to a range of concentrations of bradykinin and oxytocin were significantly enhanced by prior sensitization of the myometrium to PGF2alpha. This significant enhancing effect of PGF2alpha was only seen with the threshold dose of acetylcholine. 5. It appears that the mechanism of action of bradykinin and oxytocin on the rat uterus involves both a direct action and an indirect action. The indirect action possibly involves release of prostaglandin(s) from the endometrium.

Acetylcholine↗
PubMed1986

Effects of calcium entry blockers on tension development and calcium influx in rat uterus.

Spontaneous and potassium chloride (KCl)-induced tension development of strips of whole uterus from the day-22 pregnant rat was reduced when the tissues were incubated in a calcium ion (Ca2+)-free medium. Strips of whole uterus, in an initially Ca2+-free medium, responded to the cumulative addition of Ca2+ with graded phasic tension development and associated rapid electrical discharges. The spasms were inhibited by gallopamil (100 nM) and diltiazem (1 microM). Strips of whole uterus in a depolarizing (40 mM K+) medium, which was initially Ca2+-free, responded to the cumulative addition of Ca2+ with graded tonic tension development without associated electrical discharges. These spasms were inhibited by calcium entry blockers with a rank order of potency of nifedipine = gallopamil greater than diltiazem greater than cinnarizine. KCl-induced tension development in endometrium-free uterine strips was antagonized by calcium entry blockers with a rank order of potency of nifedipine greater than gallopamil greater than diltiazem greater than cinnarizine. Ca2+ influx into endometrium-free uterine strips was assessed by means of the 'lanthanum method'. KCl induced a concentration-dependent increase in 45Ca2+ influx which was suppressed or abolished by nifedipine (2.5 nM), gallopamil (100 nM), diltiazem (500 nM) or cinnarizine (5 microM). It is concluded that spontaneous and KCl-induced tension development of rat uterus involves Ca2+ influx from the extracellular medium into the myometrial cell. These results support the hypothesis that nifedipine, gallopamil, diltiazem and cinnarizine inhibit Ca2+- and KCl-induced tension development of rat uterus by reduction of Ca2+ influx.

Animals↗
PubMed1996

The lack of a role for potassium channel opening in the action of relaxin in the rat isolated uterus; a comparison with levcromakalim and salbutamol.

1. The effects of relaxin in vitro in the isolated uterus from the non-pregnant rat were compared with those of levcromakalim and salbutamol in tissue bath, 42K+ -efflux and electrophysiological studies, to determine whether relaxin exhibits the characteristics of an opener of KATP-channels. 2. In uterus exposed to oxytocin (0.2 nM), tetraethylammonium (TEA, 10 mM) and glibenclamide (10 microM) produced large rightward shifts of the log10 concentration-effect curve to levcromakalim (125 fold and 118 fold, respectively). TEA (10 mM) caused only small rightward shifts of the log10 concentration-effect curves to salbutamol and relaxin (5.2 fold and 7.5 fold respectively). Glibenclamide did not antagonize salbutamol or relaxin. 3. Levromakalim (0.2 and 2 microM) suppressed the spasm evoked by low ( < or = 40 mM) but not high ( > 40 mM) concentrations of KCl. Salbutamol (1.5 nM) inhibited the spasm evoked by low concentrations of KCl ( < or = 40 mM). Salbutamol (15 nM) and relaxin (3 and 30 nM) inhibited the spasm evoked by low and high concentrations of KCl (10-80 mM). 4. Relaxin (0.12 microM) did not produce an increase in 42K+-efflux from longitudinal segments of rat myometrium. Exposure of tissues to relaxin (0.12 microM), in the presence of diltiazem (1 microM) plus KCl (20 mM), resulted in a small increase in 42K+-efflux of short duration. 5. Electrophysiological recording showed that the phasic spasms of the uterus exposed to oxytocin (0.2 nM) were accompanied by bursts of spiking activity superimposed upon a plateau potential. Inhibition of the mechanical activity of the uterus by levcromakalim (2 and 10 microM), salbutamol (30 nM) or relaxin (0.18 microM) was accompanied by a reduction in the duration of the plateau potential and the number of spikes without membrane hyperpolarization. 6. Unlike levcromakalim, relaxin did not selectively inhibit the spasm evoked by low concentrations of KCl and was not markedly antagonized by TEA or glibenclamide. Under conditions where a cromakalim-induced increase of the 42K+-efflux rate has been demonstrated, relaxin had only a very small effect. In isolated uterus from the rat, in contrast to observations in vivo, relaxin did not exhibit the characteristics of an opener of KATP-channels suggesting that another mechanism accounts for its inhibitory action.

Adrenergic beta-Agonists↗
PubMed2001

Use of antisense oligonucleotides to verify the role of the alpha(1A)-adrenergic receptor in the contractility of the rat uterus post partum.

The adrenergic system plays a major role in the regulation of the contractility of the uterus during pregnancy. This study investigated the role of the alpha(1A)-adrenergic receptor (AR) in this regulation. The use of partial phosphorothioate antisense oligodeoxynucleotides (AONs) permitted the sequence-selective inhibition of AR gene expression. AONs were injected together with a cationic liposomal carrier agent into the post partum rat uterus. Incubation for 12 or 24 h with the most effective AON (480-AON) caused a 58.7 or 53.0% inhibition, respectively, of the expression of the alpha(1A)-AR density, whereas incubation for 36 or 48 h resulted in only a 38.8 or 26.7% inhibition, respectively. The decrease of the alpha(1A)-AR density by 480-AON was demonstrated by Western blot analysis and a radioreceptor binding assay on rat uterus preparations 24 h after delivery. The changes in the contractility of the uterus after AON treatment were measured on isolated rat uterine tissue by electric field stimulation. The significant decrease in the ability of the uterus to contract was indicated by the area under the curve method. The electric field studies revealed that the specific alpha(1A)-blockers 5-methylurapidil and WB 4101 inhibited the rhythmic contraction by about 74 and 70% in the control uteri and by 25 and 20% in 480-AON-treated uteri, respectively. The curves for the beta-mimetic (terbutaline) and alpha(1D)-antagonist (BMY7370) inhibitors were unchanged after 480-AON treatment of the uteri. These results suggest the importance of the alpha(1A)-AR in the tocolytic effect exerted by the alpha(1)-antagonist, although high concentrations of antagonists can not exclude the role of alpha(1D)-ARs, too. Additionally, these prove that the knockdown transformation by AONs offers a useful animal model for the investigation of receptors controlling the function of uterine tissue.

Adrenergic Antagonists↗
PubMed1982

Effects of exogenous oestrogen and experimentally induced endometritis on absorption of sodium benzylpenicillin from the cow's uterus.

The effects of oestradiol benzoate or of experimentally induced infection on the absorption of sodium benzylpenicillin from the uterus were investigated in three groups of clinically normal, non-pregnant, Friesian cows. All were at day 12 following the day of oestrus. Oestradiol benzoate in oil was administered either into the uterus or intramuscularly one hour before the infusion of 22,000 iu/kg of sodium benzylpenicillin. The dose of oestradiol benzoate was 10 mg, apart from one cow in each group which received 25 mg. Inflammation was induced by infusing a suspension of Corynebacterium pyogenes in Ringer's solution into the uterus, 11 to 18 hours before penicillin infusion. The degree of absorption of penicillin was greater in all three groups than that previously determined in cows given penicillin alone at the same stage of the cycle. The results indicate that factors which might affect blood flow to the uterus may also influence the absorption of sodium benzylpenicillin from the uterus.

Animals↗
PubMed1993

Creatine kinase isoenzymes are highly regulated during pregnancy in rat uterus and placenta.

Creatine kinase (CK) isoenzymes play a central role in energy transfer. Expression of CK isoenzymes in rat uterus and placenta was analyzed to evaluate their contribution to energy metabolism during pregnancy and delivery. Tissue from the uterine horns and placentas of pregnant rats from day 14 of gestation to 17 days postpartum was analyzed for expression of "brain" CK (BCK) and ubiquitous mitochondrial CK (uMtCK) mRNA, protein, and enzyme activity. uMtCK mRNA expression is high in prepartum uterus, but rapidly falls (> 10-fold) after delivery to a nadir at 7 days postpartum. Prepartum BCK mRNA expression is coordinate with uMtCK but has a 15-fold greater expression than uMtCK. Both CK mRNAs rise by 17 days postpartum. Both BCK and uMtCK mRNA expressions are strongly induced in placenta at 20 days gestation with a rapid fall (> 6-fold) immediately before delivery. Protein expression of BCK and uMtCK is also coordinate. However, analysis of mRNA and protein expression indicates that significant posttranscriptional regulation of both kinds of CK also occurs. CK activity in uterus and placenta reflects BCK expression. By immunohistochemistry, BCK and uMtCK protein expression is highly localized in the placenta and endometrium of prepartum uterus. This expression shifts entirely to the uterine smooth muscle by 17 days postpartum. uMtCK mRNA expression is rapidly induced by beta-estradiol in vitro (> 6-fold), demonstrating estrogen-responsive elements in the uMtCK nuclear gene. Thus a second isoenzyme of CK, uMtCK, is expressed in rat uterus and placenta and is highly regulated with BCK. These results suggest an important role for CK in the maintenance and termination of pregnancy.

Animals↗
PubMed1976

Sympathetic innervation of guinea pig uterus and ovary.

The relative contribution of the ovarian nerves and hypogastric plexus in the innervation of the guinea pig uterus and ovary was assessed. Chronic section of the hypogastric nerve did not reduce norepinephrine (NE) concentration in either organ. Localization of the hypogastric plexus in female guinea pigs was unsuccessful. Crushing the ovarian nerves 1) lowered the NE concentration in the ovary (70%) and in all portions of the uterus (86%), 2) decreased by 80-90% the uterine retention of [3H]NE, and 3) decreased the intensity of fluorescent adrenergic fibers in the uterus. However, the denervated uterus failed to exhibit supersensitivity to NE. In conclusion, sympathetic innervation of the guinea pig uterus and ovary is predominantly via the ovarian nerves, and a minor pathway of innervation may come from hypogastric plexus.

Animals↗
PubMed1988

Changes in cholinergic and noradrenergic nerves in the pregnant and postpartum uterus of the albino rat and guinea pig.

The present study was undertaken to investigate the structural changes in both cholinesterase (ChE)-positive nerve fibers and adrenergic nerves with formaldehyde-induced fluorescence in pregnant and postpartum uteri of both the albino rat and guinea pig. Particular attention was directed to the relationship between these changes and the local factors associated with the growing fetus. ChE reaction was absent in the control and pregnant uterus of the guinea pig. In the albino rat, there were signs of degeneration in pregnancy. These were evidenced by vacuolation of large nerve trunks and the presence of focal segments with very faint reaction along the course of the nerve bundles. Myometrial segments from fetus-containing horns showed some fragmented nerve fibers, but at the same time some other normal ones. Most of the fine nerve bundles gave a weak reaction. Three weeks after delivery, multiple ChE fibers were found in the uterus of the albino rat. The normal appearance was, however, not regained and some nerve fibers were still fragmented. Noradrenergic (NA) nerve fibers were disintegrated and markedly reduced in number in the myometrium of the pregnant uterus of both the guinea pig and albino rat, particularly in the uterine horns that were distended by fetuses. The number of NA fibers was not significantly reduced in the tubal ends of the albino rat uterus. Three weeks after delivery, normal NA fibers were seen in the myometrium of both the albino rat and guinea pig uterus. Nerves with reduced fluorescence reaction were observed less frequently.

Adrenergic Fibers↗
PubMed1975

Interactions of 17beta-estradiol and L-norepinephrine on the rat uterus.

Norepinephrine increased the in vitro uptake of 3H-estradiol by the uterus of spayed rats. This effect was observed at 15 and 30 min but not at 90 min. Norepinephrine also increased the binding of 3H-estradiol by the nuclear (p less than 0.02) and the cytosol fractions (p less than 0.01) when incubated with uterine homogenates, suggesting that norepinephrine does not require the presence of the intact tissue to exert its effects. The in vivo uptake of 3H-estradiol and the determination of the number of binding sites were performed in the uterus of rats treated with estradiol and estradiol plus norepinephrine. Norepinephrine alone increased the uptake of 3H-estradiol and the number of binding sites. The highest increment in both parameters was observed in the uterus of rats treated with estradiol plus norepinephrine. The estradiol Ka of the rat uterus cytosol treated with estradiol alone or plus norepinephrine was higher than that observed in the group without estradiol, suggesting the presence of different proteins that bind estradiol. These results indicate that norepinephrine increases the entrance of estradiol into the rat uterus both in vitro and in vivo.

Animals↗
PubMed1985

Metabolic quotients of the gravid uterus of the chronically catheterized guinea pig.

The uptake of substrates by the pregnant uterus defines the "diet" of the uterus and conceptus. In order to determine the uterine substrate uptake, catheters were placed in the femoral artery and uterine veins of guinea pigs at 40-49 days gestation. After at least 2 days recovery from perioperative stress, systemic arterial and uterine venous concentrations of oxygen, glucose, lactate, acetoacetate, beta-hydroxybutyrate, acetate, and free fatty acids were measured and metabolic quotients were calculated. The glucose/O2 quotient was 1.22 +/- 0.07 (mean +/- SEM), the lactate/O2 quotient was -0.40 +/- 0.09, the acetoacetate/O2 quotient was 0.03 +/- 0.02, the beta-hydroxybutyrate/O2 quotient was 0.01 +/- 0.006, the acetate/O2 quotient was 0.03 +/- 0.01, and the free fatty acid/O2 quotient was 0.24 +/- 0.21. Among the substrates measured, glucose appears to be the major metabolic fuel of the pregnant guinea pig uterus, but does not account for all of the oxygen consumed by the uterus if adjusted for lactate production, since lactate is produced within the gravid uterus in large quantities. Acetoacetate and beta-hydroxybutyrate are utilized in negligible amounts.

Animals↗