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BackgroundHigh expression of Ki67, a proliferation marker, is associated with reduced endometrial cancer-specific survival. Pre-surgical metformin reduces tumour Ki-67 expression in some women with endometrial cancer. Metformin’s anti-cancer activity may relate to effects on cellular energy metabolism. Since tumour hypoxia and glucose availability are major cellular redox determinants, we evaluated their role in endometrial cancer response to metformin.MethodsEndometrial cancer biopsies from women treated with pre-surgical metformin were tested for the hypoxia markers, HIF-1α and CA-9. Endometrial cancer cell lines were treated with metformin in variable glucose concentrations in normoxia or hypoxia and cell viability, mitochondrial biogenesis, function and energy metabolism were assessed.ResultsIn women treated with metformin (n = 28), Ki-67 response was lower in hypoxic tumours. Metformin showed minimal cytostatic effects towards Ishikawa and HEC1A cells in conventional medium (25 mM glucose). In low glucose (5.5 mM), a dose-dependent cytostatic effect was observed in normoxia but attenuated in hypoxia. Tumours treated with metformin showed increased mitochondrial mass (n = 25), while in cultured cells metformin decreased mitochondrial function. Metformin targets mitochondrial respiration, however, in hypoxic, high glucose conditions, there was a switch to glycolytic metabolism and decreased metformin response.ConclusionsUnderstanding the metabolic adaptations of endometrial tumours may identify patients likely to derive clinical benefit from metformin.

Prostanoids modulate the activity of human pregnant myometrium and their functional role can be appreciated through characterisation of prostanoid receptors and tissue concentration of prostanoids. We have applied a lipidomic approach to elucidate the profile of prostanoids in human non-labouring and labouring myometrium. We have identified a total of nineteen prostanoids including prostacyclin, thromboxanes, prostaglandins and dihydro-prostaglandins. Prostacyclin was the predominant prostanoid in both non-labouring and labouring myometria, with PGD(2) and PGF(2alpha) being the second most abundant. Although the total amount of prostanoids was increased in the labouring tissue, PGE(2) and 13,14-dihydro-15-keto-PGE(2) were the only prostanoids to increase significantly at early and late labour (p< or =0.001). Our data suggest that PGF(2alpha) plays an important role in parturition, whilst the increase in PGE(2) could occur to facilitate cervical dilation and relaxation of the lower myometrium during labour. Although the elevation in TXA(2) was less marked than expected, in terms of translation to function even a relatively small increase in the level of this potent spasmogen may have significant effects.

Treatment with some antipsychotic drugs may result in excessive body weight gain which can have detrimental effects on patient compliance, morbidity and mortality. The aim of the present study was to investigate the effect of atypical antipsychotic drugs on dietary macronutrient selection, body weight, body composition and biochemical parameters related to obesity in female rats. Forty pair-housed, adult female hooded-Lister rats (250 ± 5 g) were habituated to three diets containing principally protein, fat, or carbohydrate in a home cage self-selection paradigm. Olanzapine (2 mg/kg), risperidone (0.5 mg/kg), ziprasidone (2.5 mg/kg), or vehicle was injected intraperitoneally once daily for 22 days; food selection, water intake, and body weight were recorded daily, while body composition and plasma hormones (insulin, glucose, nonesterified free fatty acid, total cholesterol, glycerol, triacylglycerol, leptin, and prolactin) were analyzed at the end of the study. Only olanzapine significantly increased body weight and food intake. Macronutrient selection was significantly altered after olanzapine and risperidone treatment (increased protein and decreased fat preference). Only olanzapine increased carcass fat content. Locomotor activity was significantly reduced in all treatment groups. Both olanzapine and risperidone significantly increased plasma prolactin. Olanzapine was without effect on any other biochemical parameter measured. Ziprasidone significantly reduced plasma leptin and nonsignificantly reduced NEFA, while risperidone significantly reduced fasting plasma glucose. This study supports our previous work demonstrating weight gain and increased feeding behavior induced by olanzapine and could have important implications for enhancing our understanding of the mechanisms by which olanzapine and other atypical antipsychotics induce weight gain in the clinic.

Weight gain and sexual dysfunction are serious side effects of certain antipsychotic drugs. Ziprasidone, a novel antipsychotic with a unique receptor binding profile, is reported to have a low propensity for such side effects. Previous results from this laboratory have demonstrated substantial weight gain following sub-chronic treatment with olanzapine and risperidone. Risperidone induced weight gain and markedly impaired reproductive function while olanzapine induced weight gain, without affecting reproductive function. The aim of this study was to investigate effects of ziprasidone on weight gain and reproductive function in female rats. Ziprasidone (1 and 2.5 mg/kg i.p.) or vehicle was administered once daily for 28 days and body weight, food and water intake measured, in addition to histological examination of vaginal lavage to determine the stage of the oestrous cycle. On day 28, the rats were sacrificed and the uterine weights recorded, intra-abdominal fat weight and plasma prolactin levels measured. Ziprasidone failed to induce significant weight gain during weeks 1-3, however, significant weight gain was observed on day 28 at 2.5 mg/kg (p < 0.05). Ziprasidone had no effect on food intake at any time point. A significant reduction in water intake (p < 0.05) was observed during the first week of treatment with 2.5 mg/kg ziprasidone. Ziprasidone had no effect on intra-abdominal fat weight, wet or dry uterine weight or plasma prolactin levels. All ziprasidone treated animals displayed a normal four-day oestrous cycle. This study is the first to report that ziprasidone is without effect on reproductive function or ingestive behaviour in the rat.

1. The pharmacology of bimatoprost, a synthetic prostaglandin-amide, was examined in prostaglandin F(2alpha) (PGF(2alpha))-sensitive preparations. Bimatoprost potently contracted the rabbit isolated uterus (pEC(50)=7.92+/-0.16). In contrast, bimatoprost exhibited weak excitatory activity in human myometrium from pregnant and nonpregnant donors, mouse uterus, rat uterus, and endothelium-intact rabbit jugular veins, and did not stimulate DNA synthesis in mouse fibroblasts. 2. The possibility that the effects of bimatoprost may reflect partial agonism at prostanoid FP receptors was examined and the contractile effects of full agonists, 17-phenyl PGF(2alpha) (FP) and U-46619 (TP, a control), were determined in the absence and presence of 1 muM bimatoprost on the mouse uterus. Analyses of the agonist-agonist functional studies showed no antagonism, indicating that bimatoprost is not a partial agonist. 3. Bioassay metabolism studies of bimatoprost and latanoprost (FP receptor agonist prodrug) in the rabbit uterus were conducted using recipient mouse uterus. Results indicated that the potent responses to bimatoprost in the rabbit uterus are produced by the intact molecule and not by its putative free acid metabolite, 17-phenyl PGF(2alpha). Some hydrolysis of latanoprost to latanoprost free acid appears to have occurred in the rabbit uterus, according to biological detection. 4. The pharmacology of bimatoprost could not be explained by its interaction with known prostanoid FP receptors and was independent of species-, tissue-, or preparation-related factors. The potent contractile effects of bimatoprost in the rabbit uterus provide further pharmacological evidence for the presence of a novel receptor population that preferentially recognises bimatoprost.

The aim of this study was to compare the effect of two known spasmogens, oxytocin and the stable thromboxane receptor mimetic, U46619, on human myometrium treated with the prostaglandin E receptor (EP2) agonist, butaprost (selective for the EP2 receptor). Strips of myometrium from pregnant and non-pregnant donors were set up in a superfusion apparatus. Butaprost was administered as a bolus dose and via infusion. During the infusion of 10(-6) M butaprost, spasmogens were administered as bolus doses. Butaprost caused dose-related inhibition of myometrial activity when administered as a bolus dose (3-100 nmol) and concentration-dependent inhibition during infusion studies (10(-8)-10(-5 )M). Butaprost (10(-6 )M) attenuated the response to U46619 (0.l-10 nmol) in pregnant myometrium, but this difference was not statistically significant. Responses of pregnant myometrium to oxytocin (0.01-0.1 nmol) were significantly attenuated (P

Prostaglandins (PG) E2, PGF2α and thromboxane (TX) mediate uterine contractility by targeting prostonoid EP, FP and TP receptors respectively. The aim of this study was to elucidate the function of these receptors in isolated human myometrium taken at term gestation prior to and following labour onset. Lower segment myometrial strips were immersed in organ baths in oxygenated Krebs' solution at 37 °C and connected to isometric force transducers. After equilibration, spontaneous activity and concentration responses to PGE2, PGF2α and U46619 (a stable TX mimetic) were measured as area under the curve and expressed as a percentage of the final contraction induced by hypotonic shock. Results were expressed as arithmetic means±s.e.m. and analysed using two-way ANOVA with Bonferroni's post hoc test. Myometrium excised at late gestation displayed the greatest spontaneous activity compared with the tissues taken during labour (P2α (P2 at 10−5 mol/l were attenuated after labour onset. U46619 consistently stimulated concentration-dependent contractions (P

Atypical antipsychotic drug therapy may result in substantial weight gain, increased adiposity and the promotion of metabolic abnormalities. The mechanism(s) which underlie such effects remain unclear. Previous studies in our laboratory have demonstrated significant weight gain in female rats maintained on a standard laboratory diet after sub-chronic administration of olanzapine and risperidone, but not ziprasidone. The aim of this paper is to investigate the effect of antipsychotic drugs on body weight, ingestive behaviour and adiposity in female rats with access to a high fat diet. Adult female rats given free access to a high fat diet received either olanzapine (2 mg/kg), risperidone (0.5 mg/kg), ziprasidone (2.5 mg/kg) or vehicle for 28 days. Body weight, food and water intake in addition to intra-abdominal fat deposition were assessed. Olanzapine initially increased body weight but by the end of the study olanzapine animals appeared to have lost weight compared to the vehicle-treated group. Olanzapine-induced reductions in body weight were accompanied by a significant hypophagia during weeks 3 and 4. Risperidone increased body weight during week 1 only and reduced intake of a high fat diet during weeks 3 and 4. Ziprasidone was without effect on indices of body weight and ingestive behaviour. There were no effects of antipsychotic drugs on intra-abdominal fat deposition. Access to a diet high in fat attenuated weight gain induced by olanzapine and risperidone in female rats.

Gender differences in psychiatric research are becoming more widely recognized, and changes in levels of the steroid hormone, oestrogen, over the menstrual or oestrous cycle are becoming increasingly implicated in alterations in cognitive strategies and capacities. The aim of this study is to investigate the interaction between oestrogen, NMDA receptor function and cognitive processing in rats. Forty-five mature female hooded-Lister rats received vehicle, 0.5, 5 or 10 μg/kg of oestradiol benzoate (EB, s.c. in olive oil) 24 h prior to an acute dose of 2 mg/kg phencyclidine (PCP, i.p. in 0.9% w/v saline), or vehicle (0.9% saline). After 30 min following PCP treatment, animals completed the novel object recognition task with a 1 min inter-trial interval to assess object recognition memory. Results show that 5 and 10 μg/kg of EB 24 h prior to 2 mg/kg PCP significantly ( P < 0.01 and < 0.001, respectively) protected against the cognitive impairing effect of PCP in contrast to vehicle and 0.5 μg/kg EB plus PCP (not significant). EB may exert a neuromodulatory effect in this animal model leading to attenuation of the PCP-induced impairment in object recognition memory, suggesting an interaction between the gonadal steroids and NMDA receptor-mediated cognitive dysfunction, which is of potential relevance to schizophrenia.

Weight gain caused by some antipsychotics is not only confined to adults but can also adversely affect both children and adolescents. Indeed, olanzapine and risperidone have been associated with extreme weight gain in adolescents even greater than that reported in adults. We have recently shown substantial weight gain in adult female rats following treatment with olanzapine and risperidone but not ziprasidone. The aim of the present study was to compare the effects of several antipsychotics on weight gain and reproductive function in juvenile (aged 7 weeks) female hooded Lister rats. Olanzapine (4 mg/kg), risperidone (0.5 mg/kg), ziprasidone (2.5 mg/kg), sulpiride (10 mg/kg), haloperidol (0.5 mg/kg) or vehicle was administered i.p. once per day for 21 days. Body weight, food and water intake were measured daily, in addition to the determination of stage of the oestrous cycle. Sub-chronic administration of olanzapine, risperidone, sulpiride and haloperidol, but not ziprasidone, significantly increased body weight compared to vehicle-treated animals during weeks 1–3. Sulpiride significantly increased food and water intake. Significantly increased percentage intra-abdominal fat weight was observed in olanzapine, risperidone, sulpiride and haloperidol, but not ziprasidone-treated animals. Marked disruption of the oestrous cycle was observed in all but the ziprasidone-treated group, which continued to have regular 4-day oestrous cycles. Weight gain observed in these juvenile animals was 1.5–2 times greater than that previously observed in adult rats. These findings have important implications for the use of antipsychotics in children and adolescent patients.

The aim of this study was to investigate whether the response to BK on isolated human myometrium from non-pregnant (NP) and pregnant (P) donors involves the release of prostaglandin I2 (PGI2) and/or of PGE2. BK was injected as a bolus dose into the flow of the superfusate. The perfusate was collected during a response to BK and PG concentration measured by enzymoimmunoassay for PGE2 or PGI2. The BK response was biphasic, consisting of contraction followed by inhibition of myogenic activity. In tissues from both NP and P donors BK was found to cause a dose related release of PGE2 and PGI2. BK evoked PGE2 release which was greater during the contractile response than in the inhibitory response. Following the same dose of BK, PGI2 release was found to be greater in the inhibitory response than in the contractile phase. The findings indicate that in isolated human myometrium the response to BK does involve the release of PGE2 and PGI2 and in both NP and P tissue PGE2 release is greater in the contractile response phase whilst PGI2 predominates the inhibitory phase.

The purpose of this study was to investigate and compare the response of the isolated human myometrium (non-pregnant donors) and mouse uterus to bradykinin (BK), Lys-BK and des-Arg9-BK (+/-2.79 microM indomethacin). The uterine strips were set up for superfusion using Kerbs' solution. On the human myometrium the responses to BK and Lys-BK were biphasic and consisted of an increase in myometrial tension which was followed by a period of inhibition of myogenic activity. Des-Arg9-BK evoked a monophasic contractile response. On the mouse uterus the responses to BK, Lys-BK and des-Arg9-BK were monophasic and contractile only. On both of the tissues the contractile responses to BK and Lys-BK were bell shaped and indomethacin abolished the bell-shaped part of the dose response curves. The response to des-Arg9-BK and the inhibitory response to BK and Lys-BK, on the human tissue, was also significantly reduced in the presence of indomethacin. The results of this study suggest that the human and mouse uterus do posses kinin receptors of the B2 type but on human myometrium these are biphasic responses.

Sexual dysfunction is a major, although poorly understood, side-effect of treatment with antipsychotic drugs. We have recently show marked disruption of reproductive function and weight gain in female rats treated subchronically with risperidone and haloperidol. The aim of the present study was to examine further the potential relationship between reproductive dysfunction and weight gain in female rats treated with olanzapine. The effects of olanzapine on weight gain, food and water intake, intra-abdominal fat, the oestrous cycle and uterine weight were assessed in group-housed adult female hooded-Lister rats. Olanzapine (0.5-4.0 mg/kg i.p.) or vehicle was administered once daily for 21 days and body weight, food and water intake measured, with histological examination of vaginal lavage to determine the stage of the oestrous cycle. On day 22, animals were sacrificed and intra-abdominal fat, wet and dry uterine weights measured. Olanzapine induced significant weight gain with concomitant increases in food and water intake and intra-abdominal fat without an effect on the oestrous cycle, wet and dry uterine weights or plasma prolactin levels. These results confirm the ability of olanzapine to induce weight gain in female rats on unrestricted normal diet with a concomitant increase in food and water intake and increased intra-abdominal fat. These effects of olanzapine were produced in the absence of any apparent impairment in reproductive function, in contrast to the substantial disruption of oestrous and uterine atrophy previously shown in rats treated with risperidone and haloperidol.

Antipsychotic drug-induced side effects of weight gain and sexual dysfunction have clinical significance adversely affecting both compliance and morbidity. This study evaluated the effects of haloperidol and the atypical antipsychotic risperidone (0.1–1.0 mg/kg) on weight gain, food and water intake, the oestrous cycle and uterine weight in female hooded Lister rats. Haloperidol and risperidone treated rats displayed marked weight gain, although only risperidone induced significant increases in food consumption over the 21-day period. Neither haloperidol nor risperidone influenced water consumption. Marked disruption of the oestrous cycle was observed in risperidone- and haloperidol-treated animals (0.5 and 1.0 mg/kg), which was supported by significantly reduced uterine weights. The findings presented here suggest that the weight gain and sexual dysfunction induced by antipsychotics may be modelled in rodents. This model may offer insight into the mechanisms involved in mediation of such side effects.

Natural and synthetic prostanoid agonists were used to study the prostanoid receptors involved in contraction of the mature, isolated uterus of virgin rabbits. The prostanoids elicited contractile responses with a rank order of potency of PGF2 alpha, fluprostenol > PGD2 > U-46,619 > PGE2 > carbaprostacyclin with mean EC50 (nM) values of 4, 6, 34, 550, 1318 and > 10,000, respectively. Carbachol, a muscarinic agonist given after the prostanoids to elicit a reference contraction, had a mean EC50 value of 1.1 microM. The results show that the mature rabbit uterus is most sensitive to prostaglandin FP agonists and, thus, can be defined pharmacologically as an FP receptor preparation. These findings may facilitative investigations into the possibility of different prostanoid receptor populations. In the absence of useful competitive FP receptor antagonists, agonist potency data is particularly useful in systems where cross-species comparisons and tissue-related factors are not involved. The potent activities of the FP agonists, PGF2 alpha and fluprostenol, in the isolated jugular vein and uterus of the rabbit suggest that these tissues may be useful for intra-species comparisons.

The aim of this study was to determine the kinin responses on human umbilical artery (HUA) and to characterise the kinin receptors present on this tissue. The HUA was found to constrict in response to both the B 2 receptor agonist, bradykinin (BK), and the B 1 receptor agonist, des-Arg 9 -BK. The presence of indomethacin (2.79 μM) was found to have no significant effect on the responses to BK and des-Arg 9 -BK. The presence of the B 2 receptor antagonist, HOE-140 (+2.79 μM indomethacin), resulted in a concentration-related rightward displacement of the concentration-effect curves to BK. The antagonism of the constrictor responses to BK by HOE-140 was found to be competitive (pA 2 =7.5). The responses to BK were not significantly affected by the B 1 receptor antagonist des-Arg 9 (leu 8 )BK. The presence of des-Arg 9 (leu 8 )BK (+2.79 μM indomethacin) resulted in a concentration-related rightward displacement of the concentration-effect curve to des-Arg 9 -BK. The antagonism of the response to des-Arg 9 -BK by des-Arg 9 (leu 8 )BK was found to be competitive (pA 2 =5.9). The responses to des-Arg 9 -BK were not significantly affected by HOE-140. The results of the present study suggest that the products of the cyclooxygenase pathway are not involved in the kinin constrictor response on HUA and indicate the presence of B 1 and B 2 receptors on this tissue.

The pharmacological activity of two novel thromboxane A2 (TxA2)-mimetics, AGN191976 and AGN192093, was investigated in vitro, using standard organ bath assays and human platelets, to determine potency and selectivity at various prostanoid (PG-) receptors. The effects of these compounds on intraocular pressure in Beagle dogs were then compared with U-46619, a widely employed and structurally different TP-receptor agonist. AGN191976 and AGN192093 were highly potent TP-receptor agonists in the rat aorta (EC50 of 0.32 and 1.3 nM, respectively) and human myometrium. Both compounds were approximately 10 to 50 fold more potent than U-46619. These contractile responses could be blocked with a potent TP-receptor antagonist, SQ29548. In human platelets, AGN191976 (EC50 = 16.3 nM) and U-46619 (EC50 = 538.3 nM) potently stimulated aggregation (TP-receptor mediated effect), whereas AGN192093 was a much weaker agonist (EC50 = 37.9 microM). AGN192093 was not a partial agonist in platelets, since it did not antagonize aggregation induced by AGN191976, U-46619, arachidonic acid or ADP. These results provide evidence for a subdivision of TP-receptors, and AGN192093 appears to be able to distinguish between TP-receptors in smooth muscle and platelets. In the Beagle dog eye, both AGN191976 and AGN192093 were highly potent and efficacious ocular hypotensives. Single 2.5 micrograms doses of drug decreased IOP by 11.4 (AGN191976) and 7.7 mm Hg (AGN192093) relative to the contralateral control eye. In contrast, U-46619 did not lower IOP. AGN191976, but not U-46619, increased outflow facility in these animals, which is consistent with their effects on IOP. Neither compound caused miosis which is FP-receptor mediated in the dog. These studies suggest the existence of heterogeneous populations of TP-receptors. AGN191976 and AGN192093, two novel TP-receptor agonists, appear to be useful tools for the pharmacological distinction of TP-receptor subtypes.

Pickles (1967) proposed that up to four different prostanoid types existed. Coleman et al. (1984) developed a working classification for the prostanoid receptors and since then there has been some debate concerning heterogeneity of each receptor. Following on from these studies, extensive work has led to systematic prostanoid receptor classification. The present prostanoid receptor classification is a simple systematic working hypothesis whereby each of the natural prostanoids has its own receptor termed a P receptor where it is at least ten times more potent than any of the other natural prostanoids. Thus the prostaglandin E2 (PGE2)-sensitive receptors are termed the EP-receptors, PGF2α FP-receptors, PGD2, DP-receptors, PGI2, IP receptors and the thromboxane A2 (TXA2)-sensitive receptors, TP-receptors (Kennedy et al., 1982). The thromboxane receptor (TP) has been shown to mediate constriction of airway and vascular smooth muscle as well as platelet aggregation but discussion has failed to resolve the number of receptors involved.

The aim of this study was to investigate the response to bradykinin (BK) on human myometrium and umbilical artery with respect to cyclo-oxygenase (CO) products. Dose/concentration response curves to BK were performed ±2.79μM indomethacin. On human myometrium the response to BK (0.001–50 nmol) was biphasic and consisted of a dose-related increase in myometrial tension which was followed by a period of inhibition of myogenic activity. In tissues from P donors the presence of indomethacin had no significant effect on the excitatory response, but the inhibitory component of the response was reduced. In tissues from NP donors indomethacin significantly enhanced the BK effect at higher doses and the inhibitory component of the response was reduced. On the HUA cumulative addition of BK (1–1000 nM) resulted in dose dependent constriction with desensitisation at the highest dose (EC50 = 38 nM). The presence of indomethacin had no significant effect on BK response on HUA. These findings suggest that CO products contribute significantly to response to BK on the human myometrium but not on HUA and that different CO products are produced by P and NP tissue.

1. The pharmacological activity of a novel series of 9,11-cyclic carbonate derivatives of prostaglandin F2 alpha (PGF2 alpha) was investigated in various isolated smooth muscle preparations possessing different prostanoid receptor subtypes as well as in human platelets. Since subdivision of thromboxane (TP-) receptors into vascular/smooth muscle and platelet subtypes is a controversial subject, our studies included a human smooth muscle preparation (myometrium) in addition to the widely used rat aorta and human platelets as TP-receptor preparations. 2. Two members of that series, AGN191976 and AGN192093 were found to be highly potent and selective thromboxane-mimetics. AGN191976 and AGN192093 contracted isolated tissues of the rat thoracic aorta with EC50 values of 0.32 +/- 0.08 and 1.30 +/- 0.53 nM, respectively. Both agonists were at least 10 times more potent than the benchmark TP-agonist, U-46619, in this preparation, whilst being at least 500 times less potent at other prostanoid receptors (DP, EP1, EP3, FP, IP) in vitro. 3. In human myometrial strips from pregnant and non-pregnant donors, both AGN191976 and AGN192093 were potent contractile agonists. The rank order of potency in myometrium of AGN191976 > AGN192093 > U-46619 correlated well with that in the rat aorta. In human platelet-rich plasma (PRP), however, AGN191976 had potent proaggregatory activity (EC50 = 16.3 +/- 1.4 nM), which is a TP-receptor-mediated event, whereas AGN192093 was a much weaker agonist (EC50 = 37.9 +/- 2.0 microM). AGN192093 did not behave as an antagonist in the platelets, since it did not antagonize platelet aggregation induced by ADP, arachidonic acid, U-46619 or AGN191976. In human washed platelets, the activity profile of AGN191976 (EC50 = 4.15 +/- 0.52 nM) and AGN192093 (no aggregation up to 10 microM) was similar to that obtained in PRP. 4. The involvement of TP-receptors was verified with the potent TP-antagonist, SQ29548. SQ29548 (0.1 microM in myometrium; 1 microM in aorta; 1 microM and 10 microM in platelets) antagonized responses to U-46619, AGN191976 and AGN192093 as expected. 5. In conclusion, AGN191976 and AGN192093, both 9,11-cyclic carbonate derivatives of PGF2 alpha, were found to be highly potent and selective thromboxane-mimetics in rat vascular and human myometrial smooth muscle. However, only AGN 191976 was a potent agonist at TP-receptors in human platelets. The differential activity of AGN192093 on TP-receptor-mediated events in platelets and smooth muscle provides further evidence for a subdivision of TP-receptors. AGN192093 appears to be a useful tool for the pharmacological distinction of TP-receptor subtypes.

1. This study was undertaken to characterize pharmacologically the prostanoid receptor subtypes mediating constriction and relaxation of human isolated uterine artery. 2. U-46619 was a potent constrictor agonist on human uterine artery (EC50 [95% CL] = 3.5 [1.8-6.7] nM). Prostaglandin E2 (PGE2), PGF2 alpha, PGD2 and PGI2 only weakly constricted the uterine artery, being at least 100 times less potent than U-46619. The PGE2 and PGI2 constrictor effects may be modified by the potent dilator effects of these compounds. A number of agonists which show selectivity for FP-, DP- and EP-receptors including ICI 81008, BW 245C, sulprostone, rioprostil and butaprost, failed to cause any constriction at concentrations up to 30 microM. 3. Constrictor responses induced by all agonists tested were reduced or abolished by the TP-receptor blocking drugs, GR 32191 and EP 092. pA2 estimates for both antagonists versus U-46619 were 8.50, values which are consistent with their affinities at TP-receptors. 4. In preparations pre-constricted with phenylephrine (1 microM) both PGI2 and PGE2 were potent relaxant agonists. The selective IP-receptor agonists, cicaprost and iloprost, also dilated human uterine artery and were approximately 10 fold more potent than PGI2. The EP2-receptor agonists, butaprost and rioprostil and the selective DP-agonist, BW 245C, were at least 100 fold weaker than PGI2 and PGE2 suggesting that neither DP- nor EP2 receptors were involved. 5. We conclude that TP-receptors mediate constriction, whereas IP- and possibly EP4-receptors mediate relaxation of human uterine artery.

1. Prostanoid receptors present on the pregnant human myometrium in vitro have been characterized according to the receptor classification proposed by Coleman et al. (1984) using natural prostanoids and synthetic, selective analogues and antagonists where available. 2. Prostaglandin E2 (PGE2) produced a biphasic effect consisting of an initial excitation followed by a dose-related inhibition. The EP2/EP3-receptor agonists, rioprostil and misoprostol, produced similar effects to PGE2, however, the excitatory event of the misoprostol response was related to dose. The EP1/EP3-receptor agonist, sulprostone, evoked a purely excitatory response which was unaffected by AH6809. The selective EP2-receptor agonist butaprost produced a long-lasting dose-dependent inhibition of activity. The results from these prostanoids indicated that inhibitory EP2- and excitatory EP3-receptors are present on myometrium from pregnant donors at term. 3. PGF2 alpha and the synthetic FP-receptor agonist, fluprostenol, caused equipotent excitatory effects, indicating the presence of contractile FP-receptors. 4. PGD2 produced a biphasic effect of which the inhibition appeared dose-related and was antagonized by the selective DP-receptor antagonist BW A868C. The selective DP-receptor agonist, BW245C, produced a potent inhibitory effect that was competitively antagonized by BW A868C (pA2 = 8.6). 5. PGI2 produced a biphasic response qualitatively similar to PGE2. The EP1/IP-receptor agonist, iloprost, produced an occasional unquantifiable excitation and dose-related inhibition. The selective IP-receptor prostanoid, cicaprost, evoked only an inhibitory response. 6. The stable thromboxane A2 (TXA2)-mimetic, U46619, produced potent excitation which was competitively antagonized by the TP-receptor antagonist, GR32191 (pA2 = 7.2). 7. The prostanoids tested indicate that a heterogeneous population of prostanoid receptors are presen ton human myometrium from pregnant donors. It may be concluded that excitation is EP3-, FP- and TP-receptor-mediated and inhibition is EP2-, DP- and IP-receptor-mediated. Comparison of data obtained from non-pregnant specimens indicates that the lower segment tissue from pregnant donors demonstrated more pronounced responses to EP2 and IP-receptor activation.

Background Female sex steroids are not only involved in reproduction, but influence the neurobiology of brain regions involved in memory processing. Sex steroid levels are substantially elevated in pregnancy. This investigation aimed to increase understanding of the influence of sex steroids on memory, attention and mood during pregnancy. Method Pregnant participants were assessed each trimester and 3 months following birth. A non-pregnant control group were also included. A computer based assessment tool was used to assess memory and attention. Edinburgh Postnatal Depression Scale (EPDS) and General Health Questionnaire12 (GHQ12) scores were obtained and serum hormone estimation carried out. Ethics approval was obtained. Results Group mean age, verbal intelligence and body mass index were comparable (n=47). The pregnant group showed a significantly reduced spatial recognition memory (SRM) mean percent correct score compared to the control group during the second (70% SD9 vs 82% SD12, p=0.001) and third trimester (73% SD9 vs 80% SD11, p=0.03) and at 3 months following birth (68% SD10 vs 80% SD10, p=0.0001). Pregnant group mean EPDS compared to the control group mean, was significantly greater in the first and second trimester and GHQ12 scores significantly greater in the first, second and third trimester. These effects did not persist following birth. Conclusion Pregnancy seems to impair ability to remember previously seen spatial locations and this deficit remains evident at 3 months following birth. There were no significant correlations between SRM scores and sex steroids levels. Group EPDS and GHQ12 scores suggest lower mood only in pregnancy.

The uterotrophic response in the normotensive (CD) and the hypertensive (SHR) rat was compared in intact cyclic rats and in ovariectomized rats given oestradiol. The parameters measured were blood flow, and uterine wet and dry weights. In the cyclic animals blood flow to the oestogen target tissue varied throughout the oestrous cycle, peak flows being achieved at pro-oestrus; in the SHR rat, however, the pro-oestrous maximum was significantly attenuated compared with the CD rat. Uterine wet and dry weights were similar. The temporal response to oestradiol in ovariectomized rats showed that in the CD rat the hyperaemic response peaked earlier than in the SHR rat, significant changes in terms of increased water imbibition also occurred more quickly in the CD strain. In both strains, uterine dry weight was the last parameter to be significantly increased, the maximum weight being attained more quickly in the SHR rat. The results of this study indicated that it is the blood flow to the oestrogen target tissues of the uterus and vagina that is most susceptible to change with strain of rat. Journal of Endocrinology (1992) 135, 263–269

The role of thromboxane in the gravid normotensive (CD) and hypertensive (SHR) rat was investigated (by utilizing two thromboxane receptor-blocking drugs, EP092 and AH23848) both at mid-gestation and at term. The parameters examined were uterine blood flow (blood flows were measured by the microsphere technique) and uterine weight and placental blood flow at term, fetal mass and number. At mid-gestation EP092 significantly (P< 0·005) increased uterine blood flow in both strains whilst the increases seen with AH23848 were not statistically significant. At term (day 22 in the CD and day 23 in the SHR rat) the antagonists increased uterine blood flow in the CD rats alone. However, at this time the antagonists caused an increase in placental blood flow in both strains. Thromboxane appears to be involved in the regulation of uteroplacental blood flow. The observation that the antagonists were able to potentiate blood flow by mid-gestation may provide a clinical indication with respect to potential prophylactic use of this class of compounds in cases of pregnancy-induced hypertension in women. Journal of Endocrinology (1992) 135, 257–261

1 Prostaglandin F (PGF), PGD, PGI and thromboxane A2 (TXA2) receptors have been pharmacologically characterized on the non-pregnant human myometrium in vitro in accordance with the receptor classification proposed by Coleman et al. (1984). The tools for the classification include both natural prostanoids, synthetic, selective analogues and antagonists where available. 2 The potent excitatory actions of the natural FP-receptor prostanoid, PGF2α, and the synthetic analogue, fluprostenol, indicate the presence of FP-receptors mediating contraction on the human myometrium. 3 PGD2 produced a biphasic response consisting of excitation followed by relaxation of spontaneous activity of the myometrium. The selective DP-receptor agonists, BW245C, produced purely inhibitory responses illustrating the presence of inhibitory DP-receptors in this tissue. The inhibitory responses of both PGD2 and BW245C were antagonized by the competitive DP-receptor antagonist, BWA 868C, providing conclusive evidence for the existence of DP-receptors. 4 PGI2 produced a biphasic response similar to PGD2. Iloprost, the EP1/IP-receptor agonist also produced a biphasic response, whilst the IP-receptor selective agonist, cicaprost, caused inhibition only, suggesting that inhibitory IP-receptors exist in the non-pregnant human myometrium. 5 The TXA2-mimetic, U46619, produced marked stimulation of the non-pregnant human myometrium and was approximately equipotent to PGF2α and fluprostenol in this effect. The actions of U46619 were competitively antagonized by the TP-receptor antagonist GR32191 showing that excitatory TP-receptors exist in this tissue. 6 All prostanoids tested, both natural and synthetic, had activity on the non-pregnant human myometrium in vitro, supporting the existence of a heterogeneous population of prostanoid receptors in this tissue. If the results from the present study are combined with those previously reported for EP-receptor agonists (Senior et al., 1991), it may be concluded that excitation may occur through FP-, TP-, EP3- and few EP1-receptors, whereas inhibition may occur through DP-, IP- and EP2-receptors.

1. The possible role of thromboxane in the uterotrophic response to oestrogen, in the spontaneously hypertensive rat was investigated by use of the thromboxane receptor antagonists EP092, AH23848 and BM 13.505. 2. The parameters studied were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3. The antagonists attenuated oestradiol-induced uterine blood flow and significantly reduced both wet and dry uterine weight. These changes were accompanied by decreases in nuclear oestrogen receptor levels. 4. The results suggest a supportive role for thromboxane in oestradiol-induced uterine growth.

1. The thromboxane receptor antagonists EP092, AH23848 and BM 13.505 were used to investigate the role of thromboxane in the uterotrophic response to oestradiol and tamoxifen. 2. The parameters examined were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3. Only EP092 potentiated the hyperaemic response to oestrogen but all three thromboxane antagonists inhibited oestradiol-stimulated uterine growth. This inhibition was accompanied by a decrease in nuclear oestrogen receptor concentration. 4. The uterotrophic response to tamoxifen was unaffected by the thromboxane antagonists. 5. The mechanism by which the thromboxane antagonists may be exerting their growth inhibitory effect is discussed, although, whether this effect can be attributed to blockade of thromboxane receptors or to some other mechanism is not clear from this study.

The aims of this study were to elucidate further the role of histamine in the rat uterotrophic response and to investigate the differences between the oestrogen and the anti-oestrogen induced uterine responses. The parameters examined were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights. 17 beta-Oestradiol and the anti-oestrogen, tamoxifen, were used to stimulate the ovariectomised rat uterus and the antihistamines mepyramine (H1) and ranitidine (H2) were employed to modify these responses. The uterine changes evoked by oestradiol proved to be more susceptible to modification by the antihistamines than the tamoxifen-stimulated responses. The results suggest that histamine is involved in the early uterine response to oestradiol but histamine does not appear to play a major role in the uterine response to tamoxifen.

1. The effect of oestradiol on tamoxifen - (single doses of each agent) induced responses in the uterus of the mature ovariectomized rat was investigated. The parameters examined were uterine blood flow (measured by the microsphere technique), weight and oestrogen receptor concentrations. 2. Initially the addition of oestradiol to the tamoxifen regimen produced a reduction in uterine blood flow and dry weight which was reflected by a reduction in nuclear oestrogen receptor. However, as the tamoxifen response became more established from 48 h onwards the addition of oestradiol produced an additive effect. These changes were not mirrored by increases in nuclear oestrogen receptor. 3. The results suggest that tamoxifen and oestradiol may, in part, act via different mechanisms; the role of possible mediatory systems such as histamine release and eosinophil migration is discussed. Heterogeneous control systems may also be involved in the early and late uterine response.

1 The effect of a single subcutaneous dose of tamoxifen on the rat uterotrophic response was investigated. 2 The parameters examined were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3 Tamoxifen or its metabolites proved to be capable of eliciting a uterotrophic response of 35-42 days duration. The changes seen in uterine blood flow and weight are discussed in relation to oestrogen receptor distribution.

1. Prostaglandin receptors of the PGE type have been characterized in the non-pregnant human myometrium in vitro according to the scheme of Coleman et al. (1984) by use of the agonists PGE2, sulprostone, rioprostil, AY23626, butaprost, misoprostol, 16,16-dimethylprostaglandin E2, enprostil and iloprost, and, the antagonist AH6809. 2. All prostanoids tested were active in non-pregnant human myometrium either as stimulators and/or inhibitors of spontaneous activity or both. Biphasic responses to PGE2 indicate that at least two receptor types of the EP-receptor exist, one mediating relaxation and the other mediating contraction. 3. Further evidence for the EP-receptor mediating excitation and relaxation was provided by the action of the EP2-/EP3-receptor selective prostanoids rioprostil, AY23626 and misoprostol, and the EP1-/EP2-receptor selective agonist 16,16-dimethylprostaglandin E2. 4. Butaprost, an EP2-receptor selective agonist, produced potent inhibition of spontaneous activity in the tissue which was generally longer-lasting than that evoked by the natural prostanoid PGE2. 5. The EP1-/EP3-receptor selective agonist sulprostone and the EP3-receptor agonist enprostil produced potent contractile responses supporting the presence of contractile EP3-receptors in the non-pregnant human myometrium in vitro. 6. The EP1-/IP-receptor selective agonist, iloprost, produced mixed responses in non-pregnant human myometrium. The contractile response was inhibited by the EP1-receptor antagonist AH6809. However, responses to the EP1-/EP3-receptor selective agonist sulprostone were unaffected by AH6809 which may indicate that only a small population of EP1-receptors is present. 7. Therefore it would seem that a heterogeneous population of EP-receptors is present in the non-pregnant human myometrium.