Nonpregnant Human Uterus Research Articles

Uterine response to prostaglandin E 2 under oral contraceptives

The effect of prostaglandin E 2 (PGE 2) on the non-pregnant human uterus was evaluated in 35 patients. The compound was administered both by the i.v. and intra-uterine routes. Two groups of volunteers were studied; fifteen cases who were under oral contraceptives and twenty women with normal ovulatory cycles. The latter group served as the control group. The uterus under the influence of oral contraceptives showed a markedly reduced response to i.v. injections of PGE 2 at all phases of the menstrual cycles. However, the response at mid-cycle to local instillation of the compound was contradictory in the two groups, i.e. local intra-uterine instillation of PGE 2 induced uterine stimulation in pill users as compared to the usually observed uterine inhibition in ovulatory (control) cases around mid-cycle. In the proliferative and luteal phases (early and late in the cycle), the response to intra-uterine injections was qualitatively similar in the two groups but greatly reduced quantitatively in the pill user group. The implications of these findings in certain physiological processes and pathological conditions related to reproduction are discussed.

The effect of locally administered PGE 2 on the contractility of the nonpregnant human uterus [formula omitted

The effect of locally administered prostaglandin E 2 on the sensitivity and reactivity of the nonpregnant human uterus during the menstrual cycle was studied in seven women. An increase in uterine contractility in response to as little as 0.25 μg PGE 2 could be observed during both the mid-proliferative and mid-secretory phases of the menstrual cycle, but around ovulation a marked decrease in sensitivity to PGE 2 was noted. An inhibition of uterine motility was observed during menstruation in response to 30–40 μg PGE 2. Endogenous E prostaglandin normally occurs in the secretory endometrium in levels comparable to the amount of exogenous PGE 2 which elicited increased or decreased uterine activity in this study. These findings suggest that PGE 2 may play an important role in the cyclical regulation of uterine motility during the menstrual cycle.

The relaxant property of local prostaglandin E 2 on the non-pregnant uterus — A cyclic triphasic response

The response of the non-pregnant human uterus to intravenous(i.v.) injections and intra-uterine instillation of various doses of prostaglandin E 2 (PGE 2) was evaluated at the different phases of the menstrual cycle in 13 fertile regularly menstruating woemn who were neither lactating nor using any hormonal therapy. Uterine contractility was recorded by the microballoon technique in at least three sessions(proliferative, mid-cycle and secretory) in a single cycle with endometrial biopsy performed immediately following the last session to ascertain that the particular cycle was an ovulatory one. Single i.v. injections of PGE 2 had a consistent stimulatory effect on the contractility throughout the cycle with a tendency towards a decreased uterine response at mid-cycle and luteal phase as compared to the proliferative part of the cycle. Intra-uterine instilation of the compound induced a peculiar and interesting type of response. In the proliferative and secretory phases of the cycle the response was one of stimulation ; being more pronounced in the former period. However, around ovulation time, the local administration induced an evident uterine relaxation in most cases without any instance of stimulation. The possible implication of this triphasic response behaviour of the non-pregnant uterus within certain physiological events and pathological conditions is discussed.

The effect of locally administered PGF 2α on the contractility of the nonpregnant human uterus in vivo

The effect of locally administered prostaglandin F 2α on the sensitivity and reactivity of the nonpregnant human uterus during the menstrual cycle was studied. An increase in uterine contractility in response to as little as 1.0 μg PGF 2α could be observed in all patients during both the early and late portions of the menstrual cycle, but at the time of ovulation a marked decrease in sensitivity was noted. Endogenous prostaglandin normally occurs in the secretory endometrium in levels compatible with the amount of exogenous prostaglandin which elicited increased uterine activity. These findings support the hypothesis that PGF 2α plays an important physiological role in the cyclical regulation of uterine motility during the human menstrual cycle.

The effect of locally administered PGE 2 on the contractility of the nonpregnant human uterus in vivo

The effect of locally administered prostaglandin E 2 on the sensitivity and reactivity of the nonpregnant human uterus during the menstrual cycle was studied in seven women. An increase in uterine contractility in response to as little as 0.25 μg PGE 2 could be observed during both the mid-proliferative and mid-secretory phases of the menstrual cycle, but around ovulation a marked decrease in sensitivity to PGE 2 was noted. An inhibition of uterine motility was observed during menstruation in response to 30–40 μg PGE 2. Endogenous E prostaglandin normally occurs in the secretory endometrium in levels comparable to the amount of exogenous PGE 2 which elicited increased or decreased uterine activity in this study. These findings suggest that PGE 2 may play an important role in the cyclical regulation of uterine motility during the menstrual cycle.

Methods of calculating uterine blood flow from the wash-out curves of intra-arterial and local injections of 133Xenon.

The wash-out curve from the human non-pregnant uterus of intra-arterially and locally injected 133Xenon can be broken down into two, sometimes three components. It has not been shown that these components are physiologically meaningful. However, if it is assumed that the uterus is composed of two or three compartments perfused in parallel, it is possible to calculate total blood flow per unit weight using relative weights of the compartments and compartment blood flows. Relative weights may be determined from the amount of isotope present in each compartment at the start of the washout. The possibly false assumption of a certain number of compartments has in this study been avoided by evaluating curves after intra-arterial injections according to the stochastic method of Zierler analysis, disregarding any elimination of isotope left after 20 minutes. After local injections initial slope analysis has been used. The equation for values according to Zierler as a function of compartment values is y=0.9772x-0.5921, for modified Zierler analysis values y=1.2582x-2.3993 and for initial slope values y=0.8679x-1.3412. The conclusion is that compartment analysis may be a good alternative for calculation of mean blood flow, even if it has not been shown that individual compartment values are physiologically meaningful.

In vivo inhibition of the human non-pregnant uterus by prostaglandin E 2

The discrepancy between the effect of PGE 2 on the non-pregnant myometrium in vitro (relaxation) as compared to in vivo (stimulation) has not yet been solved. Nine women in the early post-menopause volunteered for the investigation. Prostaglandin (PG) F 2α or E 2 was administered either by single intravenous (i.v.) injection or by intra-uterine instillation and the uterine contractility was recorded by the microballoon technique. The response of the menopausal uterus to i.v. injections of PGF 2α or PGE 2 was characterized by rapid stimulation while intra-uterine instillation of PGF 2α induced gradual but sustained elevation of uterine tonus. However, the intra-uterine injection of PGE 2 caused inhibition of different components of uterine contractility. The fact that PGE 2 can also inhibit the in vivo motility of the menopausal non-pregnant uterus coincides with earlier in vitro results i.e. the discrepancy may not exist. Moreover, in one cycling patient (13–18th days of the menstrual cycle) similar results were also obtained. Two theories were offered to explain why PGE 2 stimulated the uterus when given as a single i.v. injection but inhibited the same organ when instilled locally into the uterine cavity.

The action of vasopressors on isolated uterine arteries

Isolated uterine arteries from nonpregnant human uteri and pregnant sheep uteri responded in a similar manner to 7 vasopressor drugs. Epinephrine and norepinephrine were equal in vasoconstrictor activity and about 10 times more active than phenylephrine and metaraminol which were also equally active. Ephedrine, mephentermine, and dopamine produced contractions of uterine arteries but only at high concentrations. Neither halothane (0.45 to 0.50 per cent), nitrous oxide (70 per cent), nor lidocaine (3 μg per milliliter) altered contractions to epinephrine or norepinephrine.

A comparison of digital and nondigital analysis of contraction records obtained from the nonpregnant uterus in vivo

A method is described to record on analogue and digital tape contractions obtained from the nonpregnant human uterus in vivo. A digital program is computed to calculate parameters comparative to: amplitude, interval, and duration of the contractions and active pressure area (APA) and linear displacement analysis (LDA) of 410 second segments of the records. Comparison of the results of the digital and of the conventional calculating method shows identical data as far as amplitude, interval, and duration of the contraction are concerned; results of APA and LDA with both methods differ to a large extent. Some difficulties in definitions and calculation procedures of the parameters of the contractions are discussed.

Accurate pressure recording in the non-pregnant human uterus. A comparison of open and closed tip catheters

The accuracy of recording intrauterine pressure in the non-pregnant uterus with open (sponge) or closed tip (balloon) catheters was investigated in vivo and in vitro. From the studies in which the manometrically induced pressure changes in an “artificial uterus” were recorded, the conclusion is reached that open tip catheter recordings are accurate and closed tip catheter recordings are not.

Resting pressure patterns in the nonpregnant human uterus

Intrauterine resting pressure has been observed by the open-end catheter technique 87 times in 26 cycles of 2 nonpregnant women. In normal cycles, the intrauterine resting pressure was substantially elevated during cycle days 10 through 22. No elevation in intrauterine resting pressure was observed during “gestagen treatment” cycles. In normal cycles there was a predictable relationship between the intrauterine resting pressure and the frequency and amplitude of contractions. The pattern of the midcycle elevation appears to follow that previously reported for estrogen excretion.

Influence of dydrogesterone on the activity of the nonpregnant human uterus

In several phases of the menstrual cycle uterine activity is characterized by distinct patterns. There is a typical “ovulatory pattern.” During drug-induced anovulatory cycles the “ovulatory pattern” is no longer present, whereas during dydrogesterone treatment no interference with the “ovulatory pattern” is seen.

Effect of ethanol on the response of the non-pregnant human uterus to oxytocin and vasopressin.

SummaryThe effect of ethanol on the response of the human uterus to oxytocin and vasopressin was studied in 11 women during the menstrual cycle. In 4 cases, the response was enhanced and in 5 it was unchanged. In 2 subjects the response after ethanol was reduced, but no more than was seen with successive doses of oxytocin and vasopressin without ethanol. It is concluded that ethanol, in doses giving blood concentrations up to 0·18 per cent, does not inhibit the response of the nonpregnant uterus to the neurohypophysial hormones.

Accurate Pressure Recording in the Non-Pregnant Human Uterus

In order to resolve some of the conflicting opinions concerning the relative accuracy of open vs. closed systems used in recording uterine activity, the various types of catheter recording systems were tested under <i>in vivo</i> and <i>in vitro</i> conditions. The findings indicate that open tip catheters accurately reflect true manometric pressures. Balloon tip catheters not only fail to record accurately, but are also subject to additional errors as the recording continues, or if there is any alteration of the fluid volume within the balloon at any time during the recording.

Effect of ethanol on the activity of the nonpregnant human uterus and its reactivity to neurohypophyseal hormones

Ethanol has previously been shown to inhibit uterine contractions during labor and lactation. Administration of ethanol during the menstrual cycle resulted in marked reduction of the uterine activity, especially during menstruation, when the activity is strongest. The uterine response to oxytocin and vasopressin was not inhibited, and by infusion of vasopressin the pretreatment activity could be restored in spite of continued alcohol administration.

In vivo studies of the motility pattern of the nonpregnant human uterus: III. The effect of anovulatory pills

The myometrial activity has been studied during cyclic and continuous treatment with contraceptive pills (norethisterone and ethinyl estradiol, Anovlar). On cyclic treatment the contractility pattern changes in the same way but more rapidly than in ovulatory cycles. On continuous treatment accentuation of the “prelabor-like” pattern is observed. Cessation of treatment is followed by “laborlike” activity. The relation between the two hormonal substances and the different activity patterns are discussed.

Slow bioelectrical potentials from the isolated fibroid nonpregnant human uterus

Slow bioelectrical potentials from the isolated fibroid nonpregnant human uterus

In vivo studies of the motility patterns of the nonpregnant human uterus: I. The normal menstrual cycle

Uterine activity was studied in 11 parous women with normal ovulatory menstrual cycles by means of the intrauterine “open-end” catheter technique. From day 6 to day 18 of 28 day cycles the same type of activity was found, i.e., frequent contractions (2 to 4 per minute) of low amplitude (3 to 10 mm. Hg) and short duration. After the eighth day before the next period, another type of contraction appeared with lower frequency (every 2 to 3 minutes), higher amplitude (around 25 mm. Hg), and longer duration (1 to 2 minutes). These contractions gradually increased and 4 days before the next period reached a “prelabor-like” pattern. A further increase to “laborlike” activity was observed around the onset of bleeding.

Inherent motility patterns and response characteristics of the nonpregnant human uterus

WIT H IN A FEW YEAR s after Schatz’ published his epochal studies of human uterine activity in pregnancy as recorded through an intrauterine estraovular bag, Heinricius” proposed a modification of the method to permit recording of activity of the nonpregnant uterus in viva through the use of a thin rubber bag. In this country, the first published record of uterine activity was by Iiucker.” The work of Knaus,“, .‘, starting in 1929. marked the beginning of a tremendous expansion of this field of study. Knaus’ original work, on which he based his primary findings conccrninz uterine activity at the various phases of the cycle and the response to pituitrin, was carried out by the injection of radiocontrast medium into the uterus through a metal cannula fitted with a rubber retaining tip, according to the standard method for hysterosalpinLyography. He then recorded changes in intrauterine prcssure through the end of the metal catheter. By 1933 he had changed to the balloon recordinz technique. A complete re\Gw of methods previously

Mode of action of prostaglandins on the human non-pregnant myometrium

Ahlqvist postulated that uteri from most mammals contain adrenergic receptors of both alpha (excitatory) and beta (inhibitory) types. These receptors should be present in human myometrium. A beta-stimulating drug such as isoxsuprine has an inhibitory action on the isolated strips of human myometrium and this effect can be inhibited by a beta-blocking agent like propranolol. It is well known that the (PGs) prostaglandins E1 E2 and E3 usually have an inhibitory action on the isolated human myometrium. Since PGE1 also has other effects that could suggest an action (stimulating or blocking) on beta receptors e.g. increase of plasma (FFA) free fatty acid in man inhibition of the catechol-induced release of FFA from fat tissue in vitro it seemed to be of interest to study whether the effect on human myometrium was mediated by andrenergic receptors. 20 strips from 5 nonpregnant human uteri were suspended in an isolated organ bath containing aerated Tyrode solution (pH 7.4 37 degrees) and the motility was recorded by levers (amplification agent proprandol in doses of 1-10 mcg/ml bath fluid completely blocked the inhibitory action of isoxsuprine and another beta stimulating drug (Cc 25 Philips-Duphar) but did not modify the response to PGE1 or to a total PG extract from (HSF-PG) human seminal fluid prepared according to Eliasson. Small amounts of PG sometimes caused stimulation of the isolated human myometrium. A few experiments (on 8 strips from 2 uteri) were also performed in which the alpha and beta blocking compounds (DHE) dehydroergotamine was used. Doses that compeltely blocked the stimulatory action of adrenaline (1-10 mcg/ml) did not modify the response to PGE1. These results show that the action of HSF-PG and PGE1 on the isolated human nonpregnant myometrium is not mediated by these adrenergic receptors. The different responses of the myometrium after changes in the extracellular concentration of potassium also indicate that isoxsuprine and HSF-PG have a different mode of action. Whether the metabolic effects of PGE1 as described above are due to interaction with the postulated beta receptors must still be determined. (Authors modified)