Peritoneal fluid prostaglandins in endometriosis, tubal disorders, and unexplained infertility

To elucidate the roles of prostaglandins in peritoneal fluid and sex steroids in patients with endometriosis (N = 29), tubal disorders (N = 15), and unexplained infertility (N = 13), assays were performed using 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) (a metabolite of prostacyclin), thromboxane B2 (a metabolite of thromboxane A2), estradiol, and progesterone. Women with normal pelvic anatomy (N = 25) served as controls. Peritoneal fluid 6-keto-PGF1 alpha concentrations in patients with endometriosis (742 +/- 104 pg/ml, mean +/- SE), tubal disorders (987 +/- 211 pg/ml), and unexplained infertility (1659 +/- 770 pg/ml) were higher than those in the control women (515 +/- 77 pg/ml). The thromboxane B2 levels in the peritoneal fluid in endometriosis (554 +/- 73 pg/ml), tubal disorders (614 +/- 107 pg/ml), and unexplained infertility (668 +/- 161 pg/ml) were higher than the levels in the control subjects (333 +/- 23 pg/ml). There was no relationship between 6-keto-PGF1 alpha/thromboxane B2 in peritoneal fluid and day of menstrual cycle. The concentrations of estradiol and progesterone were normal in all patient groups and were not related to the 6-keto-PGF1 alpha and thromboxane B2 levels. The authors suggest that these prostanoids, which may contribute to infertility, may originate mainly from the peritoneum as a result of irritation by endometriotic implants, tubal adhesions, and scarring.

Maternal thromboxane, prostacyclin, and umbilical blood flow in humans

The stable hydration products of the vasoconstrictory and proaggregatory thromboxane A2 and vasodilatory and antiaggregatory prostacyclin, ie, thromboxane B2 and 6-keto-prostaglandin F1a, respectively, were measured with radioimmunoassays from 67 women with normal pregnancy, preeclampsia, or other pregnancy complications with the determination of the blood flow in the umbilical vein with the ultrasound method. In addition, the maternal platelets' capacity to release thromboxane B2 was studied. No relation was seen between these prostanoids and the umbilical blood flow and/or pregnancy complications. Moreover, the concentrations of the prostanoids were similar in women with high (161.1 +/- 6.8 mL/minutes/kg of fetal weight, mean +/- SE, N = 33) and low (50.5 +/- 2.1 mL/minutes/kg, N = 34) umbilical flow. If thromboxane A2 and prostacyclin regulate the umbilical circulation in the human, they exert this effect locally in the fetoplacental unit, and the changes are not reflected by the levels of their metabolites in the maternal peripheral circulation.

Evidence that prostacyclin deficiency is a specific feature in preeclampsia

Much evidence has implied a deficient production of the antiaggregatory and vasodilator agent prostacyclin (PGI2) in preeclampsia and some other chronic fetoplacental insufficiency syndromes. So that we could study whether this might be due to the possible effects of the mode of delivery and maternal epidural or general anesthesia, specimens of the umbilical arteries of infants born after normal (n = 46) or complicated (n = 25) pregnancies were superfused in vitro and their production of PGI2 was determined by measuring 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha, the hydrolysis product of PGI2) by radioimmunoassay. The amounts of umbilical 6-keto-PGF1 alpha released in normal pregnancies after induced vaginal delivery (20.9 +/- 2.4 ng/gm/min dry weight of tissue, mean +/- SEM) and elective cesarean section (21.8 +/- 2.2 ng/gm/min) were smaller (p less than 0.025) than the amounts released after spontaneous onset of labor (35.0 +/- 6.2 ng/gm/min). Epidural or general anesthesia had no effect on this production. When the types of deliveries were matched, the production of 6-keto-PGF1 alpha was even less (p less than 0.05) in cases of preeclampsia (14.2 +/- 3.7 ng/gm/min; n = 9) than in the control subjects (21.3 +/- 1.6 ng/gm/min) and in cases of essential hypertension (21.6 +/- 5.2 ng/gm/min). Our data suggest that umbilical PGI2 deficiency is a specific feature of preeclampsia.

Vasoconstrictory thromboxane A2 and vasodilatory prostacyclin in climacteric women: effect of oestrogen-progestogen therapy

The production of vasoconstrictory thromboxane A2 (TxA2) and vasodilatory prostacyclin ( PG2 ) was studied in women suffering from climacteric vascular instabilities before and during the oestrogen-progestogen therapy. The serum concentrations of TxB2, a metabolite of TxA2, in climacteric patients were similar (170.5 +/- 25.5 ng/ml, mean +/- SE, n = 14) to those in control subjects (196.0 +/- 27.5 ng/ml n = 17) before the start of treatment, but rose to 209.3 +/- 24.5 ng/ml after 3 wk of treatment (P less than 0.01 in comparison with the pre-treatment level), to 227.2 +/- 44.1 ng/ml after 3 mth (P less than 0.05) and to 237.4 +/- 30.3 ng/ml after 6 mth (P less than 0.05). The plasma concentrations of 6-keto-prostaglandin F1a , a stable breakdown product of PG2 , were normal in climacteric (43.5 +/- 7.3 pg/ml as against 46.1 +/- pg/ml) and did not change during replacement therapy. It was concluded, firstly, that climacteric symptoms are not accompanied by changes in TxA2/ PG2 which can be detected in peripheral blood and, secondly, that the increase in the concentration of vasoconstrictory TxA2 induced by oestrogen-progestogen therapy may contribute to the disappearance of climacteric vascular instabilities.

Increased thromboxane A2 production but normal prostacyclin by the placenta in hypertensive pregnancies

The production of vasodilatory, antiaggregatory prostacyclin (PGI2) and vasoconstrictory, proaggregatory thromboxane A2 (TxA2) by the placenta was studied in the cases of hypertensive pregnancy complications by superfusing pieces from maternal and fetal sides of placentae of 9 pre-eclamptic, 6 hypertensive and 11 healthy women in vitro and measuring the release of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TxB2), the breakdown products of PGI2 and TxA2 respectively, from the superfusate. Both sides of the placentae from the controls produced 6-keto-PGF1 alpha (maternal side 0.5 +/- 0.1 ng/g/min dry weight of tissue, mean +/- SEM; fetal side 0.7 +/- 0.2 ng/g/min) and TxB2 (maternal side 2.5 +/- 0.4 ng/g/min; fetal side 2.7 +/- 0.5 ng/g/min) with no correlation between the two. The 6-keto-PGF1 alpha production was normal in hypertensive complications whereas the TxB2 production was increased on the fetal side of the placentae obtained from the pre-eclamptic (3.7 +/- 0.3 ng/g/min: p less than 0.05) and hypertensive women (4.1 +/- 0.4 ng/g/min; p less than 0.025). This may explain the occurrence of microthrombi and infarctions in placentae of hypertensive women.

Treatment of inadequate lactation with oral sulpiride and buccal oxytocin

Thirty-six puerperal women with inadequate lactation were treated with 50 mg sulpiride (N = 24) or placebo (N = 12) three times a day for two weeks. These treatments were supplemented with buccal oxytocin (100 IU, 300 IU, or 400 IU) or placebo preceding each breast-feeding on the sixth and 14th and on the seventh and 13th days of oral treatment, respectively. One woman treated with sulpiride and three women treated with placebo discontinued the trial because of the lack of the effect of treatment. The concentration of prolactin in maternal serum was higher (P less than .001) during sulpiride than placebo treatment at one week (380 +/- 43 ng/ml vs 23 +/- 7 ng/ml, mean +/- SE) and two weeks of treatment (381 +/- 38 ng/ml vs 34 +/- 10 ng/ml). Also, the daily breast milk yield, as measured objectively, was greater (P less than .05) during sulpiride than placebo treatment both at one week (628 +/- 51 ml vs 440 +/- 68 ml) and two weeks of treatment (684 +/- 67 ml vs 423 +/- 60 ml). Various doses of oxytocin failed to stimulate the milk secretion in the presence or absence of sulpiride-induced hyperprolactinemia. Thus, sulpiride improved inadequate lactation, whereas exogenous oxytocin alone or together with sulpiride had no effect on lactation in these mothers whose infants were able to suckle normally.

Ethanol inhibits platelet thromboxane A2 production but has no effect on lung prostacyclin synthesis in humans

Ethanol (88-880 mmol/l) inhibited the formation of proaggregatory, vasoconstricting thromboxane A2 (TxA2) during whole blood clotting and during thrombin-induced aggregation of platelet rich plasma. This inhibition was counteracted by the addition of exogenous arachidonic acid, which suggested that ethanol suppressed the liberation of arachidonic acid, evidently by inhibiting phospholipase A2. Ethanol had no effect on the formation of prostacyclin (PGI2, epoprostenol), the endogenous antagonist of TxA2, by human lung. Thus our results suggest that ethanol may shift the balance between TxA2 and PGI2 to the dominance of antiaggregatory, vasodilating PGI2 by suppressing the release of arachidonic acid in platelets. This finding might partly explain why ethanol protects against atherosclerosis and also the increased risk of subarachnoidal haemorrhage after heavy ethanol intake.

Prostacyclin and thromboxane in ovarian cancer: effect of cytostatics and prostaglandin synthesis inhibitors

The production of the antiaggregatory prostacyclin (PG1(2) ) and proaggregatory thromboxane A2 (TxA2) were studied in 19 patients with residual ovarian cancer. The plasma 6-keto-PGF1 alpha (a metabolite of PG1(2) ) in cancer patients (146.7 +/- 14.7 pg/ml, mean +/- SE) was higher (P less than 0.02) than that in the controls (85.3 +/- 9.2 pg/ml, n = 17). Also the releases of TxB2 (a metabolite of TxA2) during spontaneous clotting of the blood samples were greater (P less than 0.05) in the patients (253.4 +/- 30.1 ng/ml) than controls (183.2 +/- 19.8 ng/ml). The combined administration of doxorubicin, cyclophosphamide and cis-platinum temporarily decreased the plasma 6-keto-PGF1 alpha levels but caused no changes in TxB2 generation. Prostaglandin synthesis inhibitors (acetylsalicyclic acid or indomethacin) during cytostatic infusion did not prevent the occurrence of the acute side effects of cytostatics, but they inhibited the TxB2 generation. Thus our data suggest that residual ovarian cancer is accompanied by increased production of PG1(2) and TxA2, and that prostaglandins have no role in the acute side effects of cancer chemotherapy.

Prostacyclin and thromboxane in diabetic children

Plasma concentrations of a stable metabolite of prostacyclin, 6-keto-prostaglandin Fla (6-keto-PGF1a), and the ability of platelets to generate thromboxane B2 (TxB2), a metabolite of thromboxane A2, during spontaneous clotting of the blood were measured in 40 diabetic children and 16 healthy controls. The diabetics' platelets generated TxB2 to a lesser extent than those of controls, whereas no difference was seen in plasma 6-keto-PGF1a concentration. The balance and duration of diabetes were not related to TxB2 or 6-Keto-PGF1a. The results do not support the theory that an absolute or relative prostacyclin deficiency could trigger the onset of diabetic vascular complications.

Effect of prolonged treatment with acetylsalicylic acid and dipyridamole on platelet thromboxane A2 production in atherosclerotic subjects

We evaluated the effect of four weeks treatment with 90 mg and 1500 mg of acetylsalicylic acid (ASA), 990 mg of ASA together with 225 mg of dipyridamole and 225 mg of dipyridamole daily on the production of thromboxane A2 (TxA2) by platelets of atherosclerotic subjects. All doses of ASA studied inhibited 99% or more of TxA2 production from the third day to the end of the treatment, whereas dipyridamole did not have any effect. After the treatment, TxA2 production recovered in two weeks. Our results argue against the clinical relevance of the recent suggestions that salicylate accumulating during prolonged treatment with ASA could reduce the effect of the parent drug on the synthesis of TxA2 by platelets. Our data also dispute the inhibition of TxA2 synthesis as an antithrombotic mechanism of dipyridamole.

Relation between umbilical prostacyclin production and blood-flow in the fetus

Umbilical blood-flow (UBF) was measured by ultrasonography in 28 pregnant women. A superfusion preparation was used to investigate the production of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), a breakdown product of prostacyclin (PGI2) and thromboxane B2 (TxB2), a breakdown product of TxA2, by specimens from the umbilical arteries of the infants born to these 28 mothers and those born to 36 other women in whom UBF had not been measured. UBF was significantly related to 6-keto-PGF1 alpha production. 6-keto-PGF1 alpha production was lower in infants of the 8 pre-eclamptic mothers (14.5 ng min-1 g-1) than in those of 45 healthy mothers (26.9 ng min-1 g-1). Generation of TxA2 by the umbilical artery was 15-25 times less than that of 6-keto-PGF1 alpha, and TxA2 concentrations were unrelated to UBF or the type of pregnancy. These data provide the first evidence for a direct association between blood-flow and PGI2 generation in human vasculature.

Maternal prostacyclin, thromboxane, and placental blood flow

The vasoactive prostanoids--prostacyclin (PGI2) and thromboxane A2 (TxA2)--and their metabolites--6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TxB2), respectively--have been implicated as regulators of uteroplacental blood flow in animals. To study their roles in placental blood flow in human beings, plasma or serum samples were collected for the measurement of 6-keto-PGF1 alpha and TxB2 from 42 women during late pregnancy on the same occasion, when placental intervillous blood flow (IVBF) was determined with 133Xe isotope method. The concentrations of 6-keto-PGF1 alpha in plasma or those of TxB2 in plasma or serum were not related to the IVBF. The intravenous infusion of ritodrine for 1 hour up to the dose of 200 micrograms/min increased (p less than 0.05) the plasma 6-keto-PGF1 alpha concentrations, but caused no changes in the TxB2 levels or IVBF in seven women with premature uterine contractions. We conclude that if PGI2 and TxA2 participate in the control of placental blood flow, their changes are located in the fetoplacental unit and, thus, are not reflected by the levels of their metabolites in maternal circulation, and ritodrine may stimulate PGI2 synthesis in human beings.

Effect of vacuum curettage on the concentrations of plasma 6-keto-prostaglandin F1 alpha and serum thromboxane B2

Serial plasma samples collected before and after vacuum curettage followed by methylergometrine injection in 10 women were assayed for 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). The mean 6-keto-PGF1 alpha concentration was 97.2 (SE 8.8) pg/ml before cervical dilatation. The concentration rose to 128.2 (SE 13.5) pg/ml (P less than 0.10) immediately and to 133.3 (SE 17.8) pg/ml (P less than 0.05) 1 h after curettage and returned to the initial value within 5 h. Neither methylergometrine nor anaesthesia, nor non-gynaecological surgery, caused changes in the level of plasma 6-keto-PGF1 alpha. The capacity of the platelets to produce thromboxane A2 during spontaneous clotting of blood did not change during vacuum curettage, anaesthesia and non-gynaecological surgery, nor after methylergometrine. The evidence suggests that the pregnant myometrium and/or intrauterine tissues capable of generating prostacyclin (PGI2) in vitro may release PGI2 also in vivo.

Differential inhibition of fetal vascular prostacyclin and platelet thromboxane synthesis by nonsteroidal anti-inflammatory drugs in humans

To study the synthesis of proaggregatory, vasoconstricting thromboxane A2 (TxA2) by human fetal platelets we evaluated the formation of its stable metabolite thromboxane B2 (TxB2) during thrombin-induced spontaneous clotting of blood from the umbilical vein of 13 healthy infants. We further compared the effects of acetylsalicylic acid, indomethacin, naproxen sodium and diclofenac sodium on platelet TxA2 production in response to thrombin-induced aggregation during spontaneous clotting, and on prostacyclin (PGI2) production by umbilical arteries in a superfusion system by measuring the 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) concentration in the superfusate. For every drug four concentrations covering the clinically significant range were studied. The basal production of TxB2 by fetal platelets (181.5 +/- 22.5 ng/ml, mean +/- SEM) was comparable with that of adults (216.1 +/- 11.5 ng/ml). The concentrations of the drugs needed for 50% inhibition of TxB2 generation were 19.0 mumol/l for acetyl-salicylic acid, 0.09 mumol/l for indomethacin, 0.06 mumol/l for diclofenac sodium and 4.2 mumol/l for naproxen sodium. The basal production of 6-keto-PGF1 alpha by umbilical arteries was 24.5 +/- 3.2 ng/min/g. The concentrations of the drugs needed for 50% inhibition of 6-keto-PGF1 alpha production were 360.0 mumol/l for acetylsalicylic acid, 4.0 mumol/l for indomethacin, 2.3 mumol/l for diclofenac sodium and 15.0 mumol/l for naproxen sodium. Thus fetal platelet cyclo-oxygenase was 4-44 times more sensitive to these prostaglandin synthesis inhibitors than umbilical artery cyclo-oxygenase.

Prostaglandins and endometriosis

To study the production of prostacyclin (PGI2) and thromboxane A2 (TxA2) in endometriosis in vitro, samples of endometriotic tissue taken during operation from 6 women were superfused for 4.5 hours in 95% O2/5% CO2 at 37 degrees C, and the stable metabolites of PGI2 (=6-keto-PGF1 alpha), and TxA2 (=TxB2) were measured by radioimmunoassays from the superfusates. All samples studied produced 6-keto-PGF1 alpha in the range from 0.2 to 10.5 nanograms/gram of dry tissue/minute with a mean of 3.6 ng/g/min during the whole experiment. TxB2 was also released by each sample at rates between 0.2 and 11.9 ng/g/min (mean 2.6 ng/g/min). The production of these prostanoids tended to be greater in the serosal (n = 2) than in the ovarian (n = 4) endometriosis. The addition of indomethacin of 10(-5) - 10(-3) moles/l to the superfusion medium inhibited concentration-dependently the synthesis of these prostanoids. Apart from these in vitro data implying the production of PGs in endometriosis, 18 patients with pelvic endometriosis sustained no relief for their endometriotic symptoms from the treatments with three anti-prostaglandins (acetylsalicylic acid, indomethacin, tolfenamic acid) in a double-blind, placebo-controlled trial.

Comparison between antifibrinolytic and antiprostaglandin treatment in the reduction of increased menstrual blood loss in women with intrauterine contraceptive devices

The effects of a fibrinolysis inhibitor (tranexamic acid, TA) and prostaglandin synthesis inhibitor (diclofenac sodium, DS) were compared in the reduction of excessive menstrual blood loss in 19 women with an intrauterine contraceptive device (IUCD). These women (mean blood loss before treatment to 135.1 +/- 18.9 SE ml, range 70-294 ml) were treated in random order with TA (1.5 g three times daily for 5 days starting on the first day of menstruation for two periods), and with DS (50 mg three times on the first day followed by 25 mg three times daily for 4 days, for two periods), or with placebo (one period) in a double-blind trial. The placebo treatment did not change menstrual blood loss (128.3 +/- 15.6 ml). The TA treatment decreased blood loss to 59.4 +/- 7.7 ml (P less than 0.001) and the DS treatment to 102.1 +/- 13.6 ml (P less than 0.01). Neither treatment abolished pelvic discomfort during menstruation or shortened its duration. Various side-effects were noted by 12 women during 19 TA treatments and by five women during six DS treatments. Thus, while TA is generally far more effective, DS gave pronounced decreases in menstrual bleeding in some women and had less frequent side-effects.

Production of prostacyclin and thromboxane during cesarean section

The effect of cesarean section on the production of the antiaggregatory prostacyclin and proaggregatory thromboxane A2 was studied in 12 women by measuring the stable metabolites of prostacyclin and thromboxane A2, 6-ketoprostaglandin F1 alpha and thromboxane B2, respectively, from serial maternal blood samples collected before, during, and after the operation. The plasma 6-keto-prostaglandin F1 alpha concentration was similar to the initial concentrations before the start of anesthesia (mean 121.6 +/- SE 11.5 pg/ml), at the time of skin incision (148.0 +/- 21.0 pg/ml), and at delivery of the infant (136.3 +/- 11.2 pg/ml), but was elevated at the end of the operation (454.8 +/- 56.2 pg/ml) (P less than .001) and one hour later (233.1 +/- 39.5 pg/ml) (P less than .01). These increases were similar whether the patients were operated on under general (N = 6) or epidural (N = 6) anesthesia. The serum thromboxane B2 concentration did not change, indicating no influence of cesarean section on the capacity of the platelets to produce thromboxane B2 during spontaneous clotting. The increased output of prostacyclin may originate from the myometrium and/or intrauterine tissues, which are manipulated during cesarean section. The increased output may play a role in preventing thromboembolic complications during and after cesarean section.

Hormonal and metabolic effects of intravenous infusion of prostacyclin in healthy women

To study the hormonal and metabolic effects of prostacyclin (PGI2), 6 healthy women were infused iv with PGI2 (1, 2, 4, and 8 ng/kg/min. each for 20 min) dissolved in glycine buffer, or with glycine buffer only. Serial blood samples collected before, during and after the infusion were assayed for FSH, LH, prolactin, growth hormone, thyrotrophin, oestradiol, progesterone, testosterone, cortisol, thyroxine, triiodothyronine, renin, aldosterone, glucose, insulin, glucagon, cholesterol, high density lipoprotein-cholesterol, triglycerides, alkaline phosphatase, alanine and aspartate aminotransferases, bilirubin, sodium, potassium, chloride, calcium, inorganic phosphorous, creatinine and uric acid. PGI2 infusions were accompanied by increased levels of prolactin, growth hormone and cortisol, probably due to the stressful side-effects during PGI2 infusion. In addition, plasma renin activity, glucagon and blood glucose increased, whereas the other variables measured did not change. These PGI2-effects should be kept in mind, when PGI2 is used in clinical practice.

The effect of age on circulating 6-keto-prostaglandin F1 alpha in humans

The effect of age on the production of the antiaggregatory prostacyclin (PGI2) was studied by measuring 6-keto-PGF1 alpha in the plasma of 140 subjects (50 males and 90 females) between 10-90 years of age. The 6-keto-PGF1 alpha concentrations (mean +/- SD) in subjects between 10-20 years of age were higher (126 +/- 63 pg/ml, n = 24) than the levels in subjects between 21-30 years of age (88 +/- 30 pg/ml, n = 16), or in subjects between 51-70 years of age (88 +/- 30 pg/ml, n = 17), whereas in subjects between 71-90 years of age, the 6-keto-PGF1 alpha levels 100 +/- 59 pg/ml, n = 36) did not differ from those in subjects under 20 years of age. The 6-keto-PGF1 alpha levels in women over 70 years (118 +/- 66 pg/ml, n = 20) were higher (p = less than 0.05) than those in men of the same age (78 +/- 42 pg/ml, n = 16), but no other sex-related connections in 6-keto-PGF1 alpha concentrations were seen. Our data suggest that the PGI2 generation in vivo, as measured by 6-keto-PGF1 alpha levels in peripheral plasma, is higher in adolescence and elderly females than in the healthy adults.

Increased plasma immunoreactive 6-keto-prostaglandin F1 alpha levels in newborns with idiopathic respiratory distress syndrome

Serial plasma concentrations of immunoreactive 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), the stable hydration product of prostacyclin (PGI2), were measured with radioimmunoassay during the first month of life in 25 preterm infants with idiopathic respiratory distress syndrome (IRDS) and 38 preterm controls with normal heart and lung function. The levels of 6-keto-PGF1 alpha (521 +/- 81 pg/ml, mean +/- S.E.) in the infants with IRDS were higher (P less than 0.05) than those in the controls (335 +/- 42 pg/ml) on the first day of life, but thereafter no difference was seen. The highest first day 6-keto-PGF1 alpha level (1448 pg/ml) was found in the infant who died because of severe IRDS at the age of 19 h. The plasma 6-keto-PGF1 alpha concentrations in the distressed infants correlated positively with the alveolar-arterial oxygen gradient and the need of additional oxygen, but negatively with the arterial pH. In addition, an inverse correlation between the first day concentrations of 6-keto-PGF1 alpha and the lowest arterial oxygen tension in infants needing assisted ventilation was found. The mode of delivery (Cesarean section versus vaginal delivery) the gestational age, birth weight, sex or Apgar scores of the infants were not related to the 6-keto-PGF1 alpha levels on the first day of life. Neither did maternal pre-eclampsia, diabetes mellitus, or antenatal glucocorticoid treatment have any effect on the 6-keto-PGF1 alpha concentrations in the newborns. Our data suggest that a surge of the vasodilatory and antiaggregatory PGI2 is released during the early stage of IRDS, possibly in an attempt to increase the pulmonary perfusion. Our results give further indirect evidence that hypoxia stimulates the PGI2 production. High plasma immunoreactive 6-keto-PGF1 alpha levels during the early phase of IRDS suggest an increased generation of the vasodilatory and antiaggregatory PGI2 in this syndrome. This may be an attempt to overcome the increased pulmonary vasconstriction in IRDS. When the PGI2 formation rapidly declines after the first day of life, a relative PGI2 deficiency may ensue.

The effect of prolonged treatment with sulphinpyrazone on thromboxane A2 and prostacyclin in man

We studied the effect of 3 weeks' treatment with 4 x 200 mg of sulphinpyrazone daily (six healthy volunteers) on proaggregatory thromboxane A2 (TxA2) and antiaggregatory prostacyclin (PGI2). Platelet TxA2 production was evaluated by measuring its stable metabolite, immunoreactive thromboxane B2, from serum, and vessel wall PGI2 production by measuring its stable metabolite, immunoreactive 6-keto-prostaglandin F1 alpha in plasma. The TxA2 production (initially 209.0 +/- 27.1 ng/ml, mean +/- s.e. mean) decreased to about 30% from the second day of the treatment onwards, and it recovered in three days after the discontinuation of the treatment. PGI2 (initially 33.6 +/- 3.6 pg/ml) did not change. The shift of the balance between TxA2 and PGI2 to the dominance of antiaggregatory PGI2 during sulphinpyrazone treatment may be involved with the efficacy of the drug in the secondary prevention of myocardial infarction.

Prostacyclin and thromboxane in chronic uremia: effect of hemodialysis

To study the effects of uremia and hemodialysis on the production rates of antiaggregatory prostacyclin (PGI2) and proaggregatory thromboxane A2 (TxA2), we collected serial plasma samples from eight patients with chronic uremia before, during and after hemodialysis and assayed them for 6-keto-PGF1 alpha and TxB2, the stable metabolites of PGI2 and TxA2, respectively. In addition, the capacity of the platelets to produce TxB2 during spontaneous clotting was studied by measuring the TxB2 levels in serum incubated at +37 degrees C for 60 minutes. The PGI2 production of the uremia patients before hemodialysis was less (P less than 0.001) than that of healthy volunteers. It rose significantly following heparinization and remained elevated during hemodialysis. TxB2 generation by platelets during clotting was diminished in uremia. Plasma TxB2 levels were normal before, but increased during hemodialysis. Thus, profound changes in the PGI2/TxA2-system seem to be associated with uremia and hemodialysis.

Sulpiride improves inadequate lactation

Twenty-eight newly delivered mothers with inadequate lactation volunteered for a placebo-controlled double-blind trial of sulpiride 50 mg thrice daily for four weeks. Treatment was allocated at random, and serum prolactin concentrations and breast-milk yields were measured before and serially during the trial. Of the 26 women who completed the trial, 14 had taken sulpiride and 12 the placebo. In the sulpiride-treatment group the mean maternal serum prolactin concentration rose from 49.0 +/- SE 3.6 micrograms/l to a maximum of 402.1 +/0 43.2 micrograms/l at two weeks; in the placebo-treated group, however, the concentration fell during the trial (from 84.7 +/- 24.0 micrograms/l to 47.8 +/- 8.6 micrograms/l). Mean breast-milk yields also increased in the sulpiride-treatment group (by an average of 212-265 ml) and fell in the women given placebo. Of the 14 infants in the sulpiride-treatment group, four did not need supplementary feeds during the trial; in the control group, however, all infants continued to require such feeds. Infants in the sulpiride-treatment group gained significantly more weight than did the controls (p less than 0.05). Three women taking sulpiride complained of mild side effects, but none occurred in the infants. These findings suggest that sulpiride is an effective treatment for inadequate lactation in the puerperium.