Increases in plasma concentrations of a prostaglandin metabolite in acute airway obstruction

Plasma concentrations of a stable prostaglandin F2 alpha metabolite were measured by radioimmunoassay during and after recovery from acute airway obstruction in 15 infants. Mean (SEM) metabolite concentrations (ng/l) in plasma obtained both before (1033 (418)) and after (1470 (413)) initial treatment for airway obstruction were significantly higher than those obtained from the same subjects after resolution of the obstruction--25.5 (6.6)--and those obtained from two comparison groups. Infants positive for respiratory syncytial virus (mean 1122 (227)) had significantly higher concentrations than those who were negative (207.6 (46)). Additionally, seven subjects with a history of recurrent wheezing after resolution of airway obstruction had a significantly higher mean level (3500 (1400)) during attacks of airway obstruction than those without (600 (100)). These data suggest that prostaglandin F2 alpha mediates respiratory inflammation in airway obstruction and that trials of specific anti-inflammatory agents for the treatment of airway obstruction may be warranted.

Effect of porcine conceptus secretory proteins on interestrous interval and uterine secretion of prostaglandins

Porcine conceptus secretory proteins (pCSP) were obtained from medium in which pig conceptuses, collected on Day 15 of pregnancy, were cultured for 30 h. Culture medium was pooled, dialyzed, and concentrated by Amicon ultrafiltration for intrauterine infusion. Serum proteins (SP) were obtained from blood collected from a Day 15 pregnant gilt and diluted for intrauterine infusion. Catheters were placed into both uterine horns and the inferior vena cava of cyclic (Day 8) gilts. Single blood samples were collected at 0800 h on Days 9, 10, and 11. On Day 11, all gilts received 1 mg estradiol-17 beta (E2) i.m. at 0800 h. Protein infusions commenced on Day 12 and continued through Day 15, twice daily at 0800 h and 2000 h. Protein infusions per uterine horn were (1) 4.0 mg pCSP + 4.0 mg SP (pCSP, 4 gilts) and (2) 8.0 mg SP (SP, 4 gilts). Blood samples were collected every 15 min on Days 12 through 17 between 0805 h and 1100 h. Single blood samples were collected at 0800 h after Day 17 until gilts exhibited estrus. Concentrations of prostaglandin (PG) E, 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and progesterone (P4) were measured by specific radioimmunoassays. Interestrous intervals for pCSP-treated (18.2 days) and SP-treated (18.0 days) gilts were not different (SEM = 0.8 days) and temporal changes in concentrations of P4 in plasma did not differ between pCSP-treated (29.2 ng/ml) and SP-treated (31.2 ng/ml) gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Release of markedly increased quantities of prostaglandin D2 in vivo in humans following the administration of nicotinic acid

Nicotinic acid (niacin) is a B vitamin which is also a potent hypolipidemic agent. However, intense flushing occurs following ingestion of pharmacologic doses of niacin which greatly limits its usefulness in treating hyperlipidemias. Previous studies have demonstrated that niacin-induced flushing can be substantially attenuated by pre-treatment with cyclooxygenase inhibitors, suggesting that the vasodilation is mediated by a prostaglandin. However, the prostaglandin that presumably mediates the flush has not been conclusively determined. In this study we report the finding that ingestion of niacin evokes the release of markedly increased quantities of PGD2 in vivo in humans. PGD2 release was assessed by quantification of the PGD2 metabolite, 9 alpha, 11 beta-PGF2, in plasma by gas chromatography mass spectrometry. Following ingestion of 500 mg of niacin in three normal volunteers, intense flushing occurred and plasma levels of 9 alpha, 11 beta-PGF2 were found to increase dramatically by 800, 430, and 535-fold. Levels of 9 alpha, 11 beta-PGF2 reached a maximum between 12 and 45 min. after ingesting niacin and subsequently declined to near normal levels by 2-4 hours. Levels of 9 alpha, 11 beta-PGF2 in plasma correlated with the intensity and duration of flushing that occurred in the 3 volunteers. Release of PGD2 was not accompanied by a release of histamine which was assessed by quantification of plasma levels of the histamine metabolite, N tau-methylhistamine. This suggests that the origin of the PGD2 release is not the mast cell. Only a modest increase (approximately 2-fold) in the urinary excretion of the prostacyclin metabolite, 2,3-dinor-6-keto-PGF1 alpha, occurred following ingestion of niacin and no increase in the excretion of the major urinary metabolite of PGE2 was found. These results indicate that the major vasodilatory PG released following ingestion of niacin is PGD2. The fact that markedly increased quantities of PGD2 are released suggests that PGD2 is the mediator of niacin-induced vasodilation in humans.

Acute ozone exposure increases plasma prostaglandin F2 alpha in ozone-sensitive human subjects

Twenty O3-sensitive and 2O O3-nonsensitive subjects participated in a study to investigate the effects of disparate O3 sensitivity on plasma prostaglandin F2 alpha) responses consequent to exposure to ambient O3 concentrations. Subjects were selected from a pool of 75 normal healthy college-aged males who had been previously exposed to 0.35 ppm O3 for 1 h at an exercising VE of 60 L/min. The selection criterion used was the observed decrement in FEV1 after the O3 exposure: O3-sensitive, FEV1 decrement greater than 24%; O3-nonsensitive, FEV1 decrement less than 11%. Each subject was exposed to filtered air and to 0.20 and 0.35 ppm O3 for 80 min while exercising at a VE of 50 L/min. These experimental protocols were divided into two 40-min sessions separated by a period of 4 to 10 min. PGF2 alpha, FVC, FEV1, and FEF25-75 were evaluated before, during, and after each protocol. SGaw and Vtg were measured before and after each protocol. Plasma PGF2 alpha was significantly increased in the O3-sensitive group during and after the 0.35-ppm O3 exposure.

Effect of inhibiting prostaglandin synthesis in pregnant sheep with 4-aminoantipyrine under normothermic and hyperthermic conditions

Infusion of the prostaglandin synthetase inhibitor 4-aminoantipyrine at a rate of 20 mg/min via the fetal tarsal vein during normothermic conditions (ambient temperatures = 24 degrees C) significantly decreased the concentrations of prostaglandins E2 and F2 alpha in maternal and fetal arterial plasma and in uterine and umbilical vein plasma. The infusion was associated with a small but significant rise in fetal temperature and a fall in fetal arterial pH. Respiratory alkalosis developed in fetuses during hyperthermia by raising the ambient temperature to 43 degrees C for 8 hours. In contrast, infusion of 4-aminoantipyrine during hyperthermia produced fetal metabolic acidosis as indicated by a fall in fetal pH and an increase in PaCO2, even though the ewe remained hypocapnic. Four of the 10 fetuses died during or shortly after the 4-aminoantipyrine infusion during hyperthermia. These results indicate that uteroplacental prostaglandin synthesis is essential to allow the fetus to adapt to an increase in body temperature and suggests that prostaglandin synthetase inhibitors should be used with caution during pregnancy.

[Effect of 1-hour administration of dimethyl sulfoxide on the levels of prostaglandins, products of lipid peroxidation and beta-glucuronidase activity in the blood of patients with rheumatoid arthritis]

The effect of dimethylsulfoxide (DMSO) on the level of prostaglandins (PGE and PGF2 alpha), the intensity of peroxide oxidation of lipids (POL), activity of beta-glucuronidase (BGU) prior to and 5 and 24 hours after application made to the patients' hands was studied by a double blind method in 20 patients with genuine rheumatoid arthritis (RA) against the background of therapy with nonsteroid antiphlogistic preparations. Of 20 patients 10 received one-hour application of a 50 per cent DMSO gel, 10 patients received placebo (glycerol instead of DMSO). The authors revealed a significant suppression of PS production against the background of an increased level of POL in four patients who had been given DMSO. The activity of BGU increased five hours after application of DMSO and in 24 hours returned to the initial levels. Changes in the levels of inflammation mediators proved to be statistically insignificant in the group of patients given placebo. Thus, one-hour application of DMSO produced a substantial effect on the system of mediators and their interrelationship in patients with RA.

[Plasma prostaglandins E, E2 and F2a in nasopharyngeal carcinoma (NPC)]

The levels of prostaglandins E, E2 and F2a (PGE, PGE2, PGF2a) in plasma of NPC patients, patients with other tumors and normal individuals were monitored by radioimmunoassay. The results showed that PGE and PGE2 levels in the plasma of NPC and other cancer patients were significantly higher but the PGF2a/PGE2 ratio was obviously lower than that of the normal (P less than 0.05). But there were not much changes in the PGF2a levels (P greater than 0.05). However, no difference was found between the PG8 levels of the NPC and the other cancer patients (P greater than 0.05). Neither were there any significant changes in the PGE2 and PGF2a plasma levels and ratio of PGF2a/PGE2 in 26 NPC patients staged according to TNM classification. It is indicated that there is a relation between PGE, PGE2 and nasopharyngeal carcinoma.

[Changes in 13,14-dihydro-15-keto-prostaglandin F2 alpha and dehydroepiandrosterone-sulfate (DHA-S) levels in amniotic fluid and maternal peripheral venous blood in late pregnancy and during labor]

To study the role of prostaglandin (PG) and steroids on the mechanism of parturition, levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha (dhk.PGF2 alpha) and dehydroepiandrosterone-sulfate (DHA-S) in amniotic fluid and plasma during late pregnancy, labor, and puerperium, were measured by radioimmunoassay and gas chromatography-mass spectrometry. Seven patients at term were selected for this study and labor was induced by amniotomy. Amniotic fluid and maternal peripheral blood were obtained simultaneously from each individual at A) the artificial rupture of the membranes before the onset of labor, B) the onset of labor, C) the second stage of labor, D) the delivery, and E) 2 hours postpartum. No increase in either amniotic fluid or plasma dhk-PGF2 alpha was noticed when compared before and at the onset labor. However, there was a steady increase during labor and the maximum was reached at delivery. The dhk-PGF2 alpha concentration in amniotic fluid correlated well with that in maternal plasma. A similar pattern was observed in the DHA-S levels both in amniotic fluid and plasma. No apparent change was observed before the onset of labor, but there was a tendency to increase during labor. A significant correlation between the levels of dhk.PGF2 alpha and DHA-S in amniotic fluid was noticed. From the results obtained above, it is suggested that PG and DHA-S may be involved not in the initiation of labor but in the promotion of parturition. The biological significance of DHA-S on PG levels remains to be clarified.

Oxytocin infusion from day 10 after oestrus extends the luteal phase in non-pregnant cattle

Oestrus was synchronized in 8 cyclic heifers by progesterone treatment (PRID), after which the animals were monitored for one control cycle to measure the inter-oestrous interval. Osmotic minipumps containing saline (controls, N = 3) or oxytocin (N = 5) were implanted subcutaneously on Day 10 of the second cycle, and removed 12 days later. Jugular venous blood samples were collected daily for measurement of progesterone, and every 2 days for oxytocin. In addition, blood samples were taken every 10 min from 1 h before to 3 h after minipump insertion for measurement of plasma 15-keto-13,14-dihydroprostaglandin-F-2 alpha (PGFM) and every 30 min over the same period for measurement of progesterone and oxytocin. The lengths of the first untreated cycle in both groups of heifers were 20.2 +/- 0.56 (mean +/- s.e.m.) days compared with 25.4 +/- 0.81 days after oxytocin treatment (P less than 0.001). Oxytocin plasma concentrations in treated animals rose from less than 10 pg/ml to 70-500 pg/ml by 2 h after the start of oxytocin infusion and remained elevated until treatment was withdrawn. There was no increase in PGFM concentrations immediately after minipump insertion. Plasma progesterone concentrations were similar in treated and control animals but remained at mid-luteal levels for an average of 5 days longer in treated heifers. It is concluded that continuous administration of oxytocin can extend the luteal life-span in cattle.

Effect of prostaglandin F2 alpha on hormone concentrations in dairy cows after parturition

This study was designed to evaluate the effects of exogenous prostaglandin F2 alpha (PGF2 alpha) on hormone secretion in cows without a corpus luteum. Blood samples were taken from 10 Friesian dairy cows at frequent intervals from a jugular vein and the caudal vena cava starting between nine and 20 days after parturition. PGF2 alpha (25 mg dinoprost) was injected intramuscularly into five cows after the first eight hours of sampling. Plasma concentrations of 13,14-dihydro 15-keto PGF2 alpha (PGFM) increased rapidly but had returned to baseline by 14 hours after injection. There was no significant effect of the treatment on the time taken by the cows to resume ovarian cycles, and it had no consistent effect on plasma luteinising hormone (LH) patterns; however the amplitude of pulses of LH was temporarily suppressed in two cows and the frequency of pulses of LH was immediately increased in one cow. Treatment with PGF2 alpha had no significant effect on the concentration of oestradiol in blood from the vena cava. It is concluded that any enhancement of the reproductive performance of cows treated with PGF2 alpha after parturition is not due to a direct effect on pituitary-ovarian function.

Influence of premature rupture of membranes on induction of labor and plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha and oxytocin levels in patients with unripe cervix

Rupture of membranes at term, whether spontaneous or artificial, causes rapid and sustained increase in prostaglandin F2 alpha (PGF2 alpha) metabolite (PGFM) levels and is associated with augmentation of uterine contractions. To investigate why premature rupture of membranes (PROM) often fails to initiate uterine contractions, we measured plasma concentrations of PGFM and oxytocin (OT) in patients with PROM near term. Serial blood samples were taken before and after PROM as well as before and after local PGE2 gel application for cervical ripening. For comparison, patients with similar criteria with intact membranes were also studied, as were patients in spontaneous labor at term with and without spontaneous rupture of membranes. PROM was always associated with an initial, marked increase in plasma PGFM. Whether or not this increased PGF2 alpha production was maintained was related to the cervical status at the time of PROM. In patients with unripe cervix PGFM levels returned to initial levels within 2 hours and no contractions were elicited; when the cervix was 3 cm or more dilated, PGFM levels remained high and contractions began within 1 to 3 hours. PROM had no significant effect on plasma OT levels. When PGE2 gel was applied to ripen the cervix, PGFM levels increased moderately within 30 minutes in all patients regardless of the status of the membranes. In patients with intact membranes the concentration of PGFM in plasma declined to initial levels within 4 hours, whereas in patients with PROM, PGFM levels remained increased throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

[The use of indomethacin in acute intestinal infections]

The dynamics of the level of prostaglandins E and F was studied in 45 patients with bacterial intestinal infections. It was established that during the acute period of the disease their content showed a significant increase. Inclusion of the indomethacin (a prostaglandin inhibitor) in the complex pathogenetic treatment of intestinal infections promotes early disappearance of pathological symptoms of the disease.

[Thrombocytic hemostasis and the prostaglandin system at early stages of arterial hypertension]

In young patients with borderline arterial hypertension the system of pressor and depressor prostaglandins (PG) is activated with maintenance of their physiological proportion. In patients with I stage essential hypertension a considerable rise in the level of PGF2 alpha and thromboxane determines the system imbalance in the direction of the predominance of pressor components. The platelet hemostatic link in I stage essential hypertension is characterized by an increase in platelet aggregation activity which is mediated by the imbalance of the prostacyclin-thromboxane system in the direction to thromboxane.

Biochemical changes associated with blood pressure reduction induced by calcium supplementation during pregnancy

In a study population that comprised 34 normal black pregnant women, biochemical changes are compared between a group of women who received 1.5 gm of calcium supplementation a day and a group of women who received placebos. The blood pressure-lowering effect of calcium supplementation appears to involve a mechanism that relates parathyroid hormone and plasma renin activity. Other alterations in calcium and magnesium metabolism, as reflected by increased urinary calcium excretion and serum magnesium levels, may also contribute to this effect. Subgroups of study participants with initial (less than 26 weeks' gestation) low levels of serum calcium and plasma renin activity are the ones with the largest reductions in blood pressure. Whether these alterations can produce a reduction in the incidence of pregnancy-induced hypertension is the next question to be answered in this area.

Mating increases plasma levels of prostaglandin F2 alpha in female garter snakes

Plasma levels of prostaglandin F2 alpha (PGF2 alpha) in female red-sided garter snakes (Thamnophis sirtalis parietalis) were measured at intervals after mating or exposure to males. PGF2 alpha levels increased significantly within 15 minutes of mating and peaked 6-24 hr after mating. Females that did not mate, but received similar amounts of male courtship, had levels of PGF2 alpha significantly lower than those of females that mated. These results extend previous findings that unmated female garter snakes injected with PGF2 alpha exhibit sexual behavior characteristic of females that have mated. Together these data indicate that female garter snakes elaborate PGF2 alpha in response to stimuli associated with mating and that PGF2 alpha has a functional role in inducing post-mating declines in sexual behavior of this species.

Effect of food withdrawal on arterial blood glucose and plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha concentrations and nocturnal myometrial electromyographic activity in the pregnant rhesus monkey in the last third of gestation: a model for preterm labor?

Pregnant rhesus monkeys were studied between 109 and 149 days of gestation. Food withdrawal for 48 hours (with free access to water) was accompanied by a decrease in maternal whole blood glucose concentration and an increased maternal arterial plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha concentration. On successive nights of the 48-hour period of food withdrawal, there was an increase in the frequency of myometrial contractions as recorded by uterine electromyogram. In the period after food was returned, blood glucose, arterial 13,14-dihydro-15-keto-prostaglandin F2 alpha concentration, and contraction frequency returned to baseline. Because food withdrawal results in the appearance of the nocturnal contraction pattern seen at term, we suggest that this experimental paradigm may be used as a model for preterm labor.

Chronological relationships between mediator release and changes in airway dynamics during an ascaris response in sensitive cynomolgus monkeys

Recently identified Ascaris suum sensitive cynomolgus monkeys were further characterized to determine if a chronologic relationship existed between mediator release and onset of bronchoconstriction. In these anesthetized Ascaris-sensitive monkeys, aerosol antigen challenge of each animal produced rapid and severe bronchoconstriction, as determined by decreases in dynamic lung compliance (-80.2 +/- 4.1%) and airway conductance (-64.5 +/- 13.8%). Maximum changes were achieved within 5 min following exposure and remained substantially altered throughout the 30 min observation period. However, changes in pulmonary function related to duration of onset and maximum change seemed to have some correlation with each animals' sensitivity to the antigen. Comparison of pre- and post-challenge blood gas profiles, showed a progressive formation of respiratory acidosis through decreases in arterial blood pH, partial pressure of O2 (pO2), O2 saturation (sO2) and an increase in partial pressure of CO2 (pCO2). When arterial blood plasma was assayed by RIA for mediators of anaphylaxis, large increases in 5-hydroxyeicostetraenoi acid (5-HETE), leukotriene B4 (LTB4) and histamine were observed. No amount of prostaglandin F2-alpha (PGF2 alpha) or thromboxane A2 were detected. Two of the three monkeys also produced detectable amounts of leukotriene C4 (LTC4). Therefore, in Ascaris-sensitive monkeys, histamine is the predominate mediator released and is probably responsible for at least the early part (5-10 min) of the observed bronchoconstriction. However, mediators from the lipoxygenase pathway may also be playing a role in the antigen-induced bronchoconstriction, especially beyond the 10 min period following anaphylaxis.

Evidence for involvement of prostaglandins in central alpha adrenergic activity and LH release in sheep

Circhoral pulsatile release of immunoreactive luteinising hormone (LH) and prostaglandin F2 alpha (PGF2 alpha) occur synchronously into the jugular vein in ovariectomised sheep. Following a 4-hour control period, intra-carotid injections of phentolamine or intramuscular injections of phenoxybenzamine were given to ovariectomised sheep and the pulsatile release of LH and PGF2 alpha was monitored for a further 6 to 8 hours. Phenoxybenzamine caused a fall in LH and PGF2 alpha in jugular venous plasma. Phentolamine also reduced LH significantly but in this case a marked rise in PGF2 alpha as measured by radioimmunoassay (RIA) occurred after very high doses of phentolamine. Interpretation of the latter results was complicated by the fact that phentolamine at high dose levels interfered with the RIA of PGF2 alpha in plasma. Experiments were repeated in ovariectomised sheep with cannulae placed in the lateral ventricles of the brain for sampling cerebrospinal fluid (CSF). In contrast to the previously observed rise in jugular venous PGF2 alpha following high doses of phentolamine, a fall in CSF levels of immunoreactive PGF2 alpha occurred following intracarotid phentolamine or phenoxybenzamine in 3 out of 7 experiments, while no change was observed in the remaining 4 animals. Phentolamine did not reduce LH significantly in animals with intraventricular cannulae. The work provides support for the view that circhoral pulses of immunoreactive PGF2 alpha in sheep are neural in origin and may be related to sympathetic neurotransmission.

Prostanoids during acute sarcocystiosis in growing pigs

The stable metabolites of thromboxane A2, prostaglandin E2, and prostaglandin F2 alpha (TxB2, PgEM, and PgFM, respectively) were measured in the blood plasma of nine castrated male pigs, each inoculated with 2 x 10(5) sporocysts of Sarcocystis miescheriana (group A), and in that of nine non-infected controls (group B). All infected pigs developed mild disease, the clinical signs being most severe between days 14 and 17 post infection (p.i.). In the infected pigs of group A, the TxB2 plasma levels increased with the onset of the acute phase of illness (12 days p.i.), reaching peak values at day 14 p.i. The mean TxB2 values were significantly higher in the infected pigs from day 12 p.i. until the termination of the experiment on day 21 p.i. The PgEM values increased steadily in the infected pigs from day 12 p.i. until day 21 p.i. but remained relatively constant in the control pigs during the same period. In contrast, PgFM values remained low in the infected pigs throughout the experiment, and no significant differences between infected and non-infected pigs could be found. We conclude that the elevated TxB2 and PgEM values reflect a major involvement of prostanoids in the pathogenesis of sarcocystiosis.

Counter current transfer and back transport of 3H-PGF2 alpha in the cow's broad ligament vasculature ipsilateral and contralateral to the corpus luteum

Eight cows of similar age (5-7 years) were chosen for the experiment. Isolated reproductive tract was supplied with autologous oxygenated and heated (40 degrees C) blood through the uterine artery and ovarian artery. 3H-PGF2 alpha in total dose of 2 MBq (10(7) cpm) was injected into each of the uterine lumen of isolated organ. Blood samples were collected at 5 min intervals during 120 min of experiment using cannulae inserted into the branches of uterine arteries about 1 cm below the horns and from ovarian arteries inserted 0.5 cm below the ovaries. The concentration of 3H-PGF2 alpha found in blood plasma taken from uterine artery or from ovarian artery on the side with active corpus luteum (CL) was significantly lower (p less than 0.001) compare with contralateral side to active CL. Radioactive PGF2 alpha found in branches of uterine arteries on both ipsilateral and contralateral side to CL was significantly higher (p less than 0.001) compare to ovarian artery of the same side. It is concluded that absorption of 3H-PGF2 alpha from uterine lumen into venous blood as well as its counter current transfer in area of broad ligament vasculature were reduced on the side of uterine horn with active CL probably as an effect of estrogen:progesterone ratio on vascular constriction in area of uterine vasculature.

Effect of 3-methylindole on the plasma and lung concentrations of prostaglandins and thromboxane B2 in goats

1. The role of prostanoids in 3-methylindole (3MI)-induced lung disease was investigated. Goats were infused with 3MI in propylene glycol at a dose of 35 mg 3MI/kg body weight. Control goats were infused with propylene glycol alone. 2. Blood was collected at regular intervals starting 24 hr before and ending 72 hr following 3MI infusion. In a second experiment, 3MI-treated goats were killed at 2, 6, 12, 24, 48 and 72 hr post-infusion. The concentrations of PGF2 alpha, PGE, 6-keto PGF1 alpha and TXB2 in plasma and lung of 3MI-infused and control goats were determined by radioimmunoassay. 3. Comparison of individual prostanoid concentrations showed that 3MI-infused and control goats exhibited similar plasma profiles for all four prostanoids measured. 4. In addition, prostanoid concentrations in lungs did not seem to be affected by 3MI infusion. 5. Thus, plasma and lung prostaglandin and TXB2 concentrations do not appear to be altered in 3MI-induced lung disease.

Changes in plasma levels of PGF2 alpha and PGI2 metabolites at and after delivery at term

Plasma levels of 6-keto-PGF1 alpha and 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured by high pressure liquid chromatography and radioimmunoassay during and up to 48 hours after term labor. PGFM levels increased during labor to reach values which at full dilatation, at delivery of the fetal head and at placental separation were each time higher than levels obtained earlier. In all women (n = 10) PGFM levels reached their maximum and started to decline within 10 min. after placental separation. Levels decreased to prelabor values within 2 to 3 hours after delivery and no temporary increases were observed within the first 2 days. Levels of 6-keto-PGF1 alpha on the other hand, showed no consistent trends throughout labor and the early puerperium. The observed changes are believed to be of relevance for ensuring adequate hemostasis after birth.

The influence of flunixin on the response to Salmonella typhimurium endotoxin in calves

The effects of intravenous injection of 0.5 microgram/kg body weight of Salmonella typhimurium endotoxin were studied in calves. The injection was followed by ruminal stasis and general dullness. The clinical signs disappeared within 24 hours. The injection was followed by a tremendous increase in the plasma level of 15-ketodihydro-PGF2 alpha, the main metabolite of PGF2 alpha. The injection was also associated with a profound leukopenia and significant decreases in the serum levels of iron, zinc and calcium. In order to study the role of prostaglandin (PG) for the development of endotoxin-induced changes a group of calves was pretreated with flunixin, a potent cyclo-oxygenase inhibitor, at a dose of 2.2 mg/kg body weight. Flunixin inhibited the PG release completely, but did not influence the other responses to endotoxin. The pyrogenic response to endotoxin was very moderate and it was suggested that fever is not the most suitable parameter for monitoring endotoxin effects in calves. The studied blood parameters (15-ketodihydro-PGF2 alpha, iron, zinc, calcium and the number of leukocytes) appeared to be much more sensitive.

[Activity of the sympathetic nervous system and the levels of prostaglandins and intracellular electrolytes in patients with arterial hypertension and low plasma renin activity]

Differential-diagnosis tests for low-renin hypertension viz essential hypertension and arterial hypertension due to Conn's syndrome (adrenocortical adenoma or hyperplasia) have been assessed. The examined patients showed considerable humoral and metabolic differences, as compared to patients with high and normal plasma renin activity (PRA). For example, patients with essential hypertension and low PRA showed depressed noradrenalin and PGE2 secretion, increased PGF2 alpha secretion, low triglyceride level, and elevated erythrocyte sodium content. Patients with adrenocortical adenoma exhibited increased secretion of adrenalin, dopamine and PGF2 alpha, and a higher erythrocyte sodium level. Enhanced dopamine synthesis in patients with Conn's syndrome may be an adaptive response to a high aldosterone level.

Enhanced vasoconstrictor responses to potassium, 5-hydroxytryptamine, and prostaglandin F2 alpha of isolated coronary arteries from magnesium-deficient rats. Comparison with vasomotor activity of aorta

Wistar rats were fed a low magnesium diet for 8 or 12 weeks, resulting in reduced levels of magnesium in plasma, heart, and skeletal muscle, as compared with pair-fed control rats. The magnesium-deficient rats also had reduced tissue levels of potassium. Coronary arteries and thoracic aorta from magnesium-deficient rats and control rats were incubated in tissue baths and the contractile responses to potassium, 5-hydroxy-tryptamine, and prostaglandin F2 alpha were investigated using a sensitive in vitro system. The concentration-contraction curve, for all agents was shifted to the left in coronary arteries from magnesium-deficient rats. In aorta from magnesium-deficient rats, the pattern of change in reactivity to these agonists was not uniform: the concentration-contraction curve for 5-hydroxytryptamine was shifted to the left, the contractile response to prostaglandin F2 alpha was reduced, while there was no change in the response to potassium. The contractile response to the administration of calcium to calcium-depleted, potassium-depolarized vessels from magnesium-deficient rats was enhanced; the effect was more pronounced in coronary arteries as compared to the aorta. Hence, the vasomotor reactivity of coronary arteries appears to be more sensitive than is the aorta during magnesium-deficient conditions.

Evidence for prostaglandin involvement in early luteal regression of the superovulated nanny goat (Capra hircus)

Feral does of various ages were treated with intravaginal progestagen sponges for 16 days to synchronize oestrus. On Day 2 before sponge removal the goats were given 1200 i.u. PMSG to induce superovulation: 6 of the goats were also injected every 12 h with flunixin meglumine, a prostaglandin (PG) synthetase inhibitor, from Day 3 to 7 of the synchronized oestrous cycle. Jugular blood samples were collected from all females into heparinized syringes at daily intervals over the 2 days before sponge removal, twice daily for the next 2 days, then at hourly intervals from 09:00 to 17:00 h for 2 days and then twice daily for a further 2 days, for measurement of plasma progesterone and the PGF metabolite 13,14-dihydro-15-keto-PGF (PGFM) by radioimmunoassay. Intermittent surges in plasma PGFM concentrations were observed in hourly samples collected from 4/4 untreated females but in only 2/6 of the inhibitor-treated females (P less than 0.05), and the peak plasma PGFM concentrations were reduced in these 2 inhibitor-treated goats compared with the control goats. The corpora lutea (CL) of the inhibitor-treated females appeared to be functional as indicated by the plasma progesterone profile and endoscopic examination of CL. In the control females, however, there was evidence of premature regression of CL. These results suggest that the premature release of PGF-2 alpha may be the cause of premature regression of CL in nanny goats induced to superovulate.

Intraluteal infusion of a prostaglandin synthesis inhibitor, sodium meclofenamate, causes premature luteolysis in rhesus monkeys

The physiological significance of locally produced prostaglandins (PGs) in the regulation of the functional lifespan of the primate corpus luteum is unknown. In the current study, the PG synthesis inhibitor sodium meclofenamate was administered to adult female rhesus monkeys beginning in the midluteal phase of the menstrual cycle. Meclofenamate was infused continuously for 7 days into the corpus luteum (100 micrograms/h, n = 6) or the jugular vein (100 micrograms/h, n = 3; 1000 micrograms/h, n = 3) via osmotic minipump. As controls, PBS was infused into the corpus luteum (n = 7) or jugular vein (n = 5). In some of the monkeys receiving intraluteal infusions, chronic aortic and utero-ovarian venous catheters were implanted, and blood samples were collected on alternate days for the measurement of PGE and PGF2 alpha by RIA. Saphenous venous blood was collected daily, and progesterone and cortisol levels were determined by RIA. LH levels were determined by the mouse Leydig cell bioassay. Progesterone levels over 5 days preceding treatment were not different among groups. A decline in progesterone levels on day 1 after surgery was observed in all treatment groups and was accompanied by a 1-day elevation in cortisol levels. Thereafter, five of seven monkeys who received intraluteal infusions of PBS displayed normal progesterone patterns during treatment and normal luteal phase lengths of 15.4 +/- 1.2 days (mean +/- SEM). In six monkeys that received intraluteal infusions of meclofenamate, progesterone levels typically fell to less than 1 ng/ml within 72 h after initiation of infusion; progesterone levels during 7 days of intraluteal infusion were significantly lower (P less than 0.01) in meclofenamate- vs. PBS-treated monkeys. Meclofenamate infusion into the corpus luteum significantly shortened (P less than 0.01) the luteal phase to 10.5 +/- 1.0 days. In contrast, progesterone levels during 7 days of meclofenamate infusion into the jugular vein did not differ from those in PBS-treated monkeys, and the length of the luteal phase was unaltered. LH levels, measured daily, did not differ among groups either before or during treatment. Although an venous/arterial gradient in PGE was detected at the time of surgery, we were unable to detect a significant gradient across the ovary in PGE or PGF2 alpha at any time after surgery in monkeys treated with either PBS or meclofenamate. The present data suggest an obligatory luteotropic role for locally produced metabolites of arachidonic acid, but a physiological role for either PGE or PGF2 alpha in regulating the primate corpus luteum remains equivocal.

Effect of ovine conceptus secretory proteins and purified ovine trophoblast protein-1 on interoestrous interval and plasma concentrations of prostaglandins F-2 alpha and E and of 13,14-dihydro-15-keto prostaglandin F-2 alpha in cyclic ewes

Conceptus secretory proteins (oCSP) were obtained from medium in which sheep conceptuses, collected on Day 16 of pregnancy, were cultured for 30 h. A portion of the culture medium (500 ml) was prepared for intrauterine infusion by concentrating the proteins by Amicon ultrafiltration (Mr 500 cutoff). A second portion (500 ml medium) was used to purify sheep trophoblast protein one (oTP-1). Proteins remaining after oTP-1 purification were concentrated and then passed through an anti-oTP-1 sepharose CL-4B affinity column to remove any remaining oTP-1 (oCSP-oTP-1). Serum proteins (oSP) were collected from a Day-16 pregnant ewe and diluted for infusion. Catheters were placed in the uterus of cyclic (Day 10) ewes. The following combinations of proteins were infused: 0.75 mg oCSP + 0.75 mg oSP (5 ewes), 0.75 mg oCSP - oTP-1 + 0.75 mg oSP (4 ewes), 0.05 mg oTP-1 + 1.45 mg oSP (5 ewes) and 1.5 mg oSP only (5 ewes). Infusions were twice daily on Days 12 and 13 (08:00 and 17:00 h) and once on Day 14 (08:00 h). On Day 14, ewes were injected intravenously at 08:00 h with 0.5 mg oestradiol-17 beta. Blood sampling began 30 min before oestradiol injection and continued every 30 min for 10 h. On Day 15 ewes received 10 i.u. oxytocin intravenously (08:00 h). Blood samples were collected 10 min before oxytocin and every 10 min for 1 h after oxytocin injection. Concentrations of prostaglandin (PG) F, PGE-2/PGE-1 (PGE) and 13,14-dihydro-15-keto-PGF-2 alpha (PGFM) were measured by specific radioimmunoassay. Ewes treated with oTP-1 and oCSP had longer (P less than 0.05) interoestrous intervals (27 and 25 days, respectively) compared to ewes treated with oSP and oCSP--oTP-1 (19 and 19 days, respectively) (s.e.m. = 1.56 days). These results indicate that oTP-1 alone is as potent as total conceptus secretory proteins in extending luteal maintenance. Ewes treated with oTP-1 and oCSP had no increase in PGF after oestradiol injection while production of PGF did increase 6-10 h after oestradiol in ewes treated with oSP and oCSP--oTP-1. PGFM was correlated with PGF concentrations (r = 0.57, P less than 0.01) although presence or absence of increases in production of PGFM for the treatment groups were not the same as those for PGF. No effects of treatment on PGE were detected.(ABSTRACT TRUNCATED AT 400 WORDS)

Variation in plasma concentrations of oestradiol-17 beta and their relationship to those of progesterone, 13,14-dihydro-15-keto-prostaglandin F-2 alpha and oxytocin across pregnancy and at parturition in pony mares

Concentrations of plasma progesterone were similar to values reported in the literature except that a significant decrease in progesterone during the last day, but before parturition, was detected by systematic, high-intensity blood sampling. Mean concentrations of oestradiol-17 beta increased sharply and significantly, plateaued for 132.8 +/- 1.5 days (mean +/- s.e.m., N = 9), then declined sharply in each mare. There was obvious variation between the mares in when these increases and decreases in oestradiol-17 beta occurred, with the events being related closely to ambient photoperiod conditions rather than to the stage of pregnancy. Concentration of 13,14-dihydro-15-keto-prostaglandin F-2 alpha (PGFM) remained at low levels (less than 400 pg/ml) until Day 200 then increased to peak pregnancy levels (greater than 2000 pg/ml) by Day 300 and remained at this value until parturition. The concentrations of oxytocin remained basal (less than 15 microU/ml) throughout pregnancy and increased only at the beginning of the expulsive stage of labour. There was an increase, although not statistically significant, in the relative concentrations of oestradiol-17 beta to progesterone beginning 3 days before parturition, with the highest value of the ratio occurring at fetal delivery. Far more striking were acute changes in PGFM and oxytocin during parturition. Maximal concentrations of PGFM (approximately 30 ng/ml) and oxytocin (greater than 200 microU/ml) were measured between rupture of the chorioallantois and the completion of delivery. Closely timed samples from one animal showed that oxytocin increased (more than 10 standard deviations of the mean levels during late pregnancy for this animal) before any change in PGFM. In another dystocic mare, both oxytocin and PGFM peaked in the initial stages of delivery but only oxytocin remained elevated until the dystocia was remedied. The results suggest that an abrupt increase in oxytocin secretion precipitates the expulsive phase of parturition in mares.

Elevated concentrations of 13,14-dihydro-15-keto-prostaglandin F-2 alpha in maternal plasma during prepartum luteolysis and parturition in dogs (Canis familiaris)

Concentrations of progesterone and of 13,14-dihydro-15-keto-prostaglandin F-2 alpha (PGFM) were measured in plasma collected from 6 bitches every 3 h starting 2.8-4.6 days before parturition (birth of first pup) and continuing until 0.4-0.8 days post partum, and in additional samples collected less frequently. Progesterone concentrations at 48, 24, 12 and 3 h pre partum averaged 2.8 +/- 0.3, 2.2 +/- 0.4, 1.0 +/- 0.3 and 0.7 +/- 0.2 ng/ml. At those times PGFM values averaged 380 +/- 80, 800 +/- 220, 1450 +/- 450 and 1930 +/- 580 pg/ml, respectively. Mean concentrations of PGFM increased about 2.5-fold between 48 and 15 h pre partum in association with the onset of luteolysis, and then increased another 2.5 times before parturition as progesterone fell to nadir values. Peak levels of PGFM ranged from 1060 to 7150 pg/ml (2100 +/- 600 pg/ml) and occurred within 1-9 h after the birth of the first pup and before the birth of the last pup. These results suggest that prepartum luteolysis in dogs is initiated by increases in maternal concentrations of PGF, and that progesterone withdrawal causes a further increase in PGF which completes luteolysis and provides a major portion of the uterotonic activity causing expulsion of pups.

Hormonal changes during luteal regression in farmed fallow deer, Dama dama

Concentrations of progesterone, oxytocin and PGFM (pulmonary metabolite of PGF-2 alpha) were measured in plasma from peripheral blood samples collected from 5 fallow does every hour or 2 h for 12-h periods on Days 15-20 inclusive of the oestrous cycle (i.e. luteolysis). For 3 does that exhibited oestrus on Day 21, plasma progesterone concentrations fluctuated between 3 and 10 ng/ml on Days 15-18 inclusive. Thereafter, values declined progressively to attain minimum concentrations of less than 0.05 ng/ml on Day 20. Basal concentrations of plasma oxytocin and PGFM fluctuated between 5 and 20 pg/ml and 10 and 100 pg/ml respectively. Episodic pulses of plasma oxytocin (greater than 300 pg/ml) occurred on Days 15 and 16, whereas pulses of plasma PGFM (greater than 400 pg/ml) occurred on Days 19 and 20. There was little apparent correlation between episodic pulses of the two hormones. For 2 does that exhibited oestrus on Day 22, plasma progesterone concentrations declined to minimum values of 1.0-1.5 ng/ml by Day 20. One of these does showed very high levels of oxytocin secretion throughout the sampling period while the other showed an apparent paucity of oxytocin secretory periods. Two does hysterectomized on Day 13 of their second oestrous cycle failed to exhibit further oestrous cycles. Continual elevation of plasma progesterone concentrations (2-6 ng/ml) for an 8-month period indicated persistence of the corpus luteum after hysterectomy. It is concluded that luteolysis in fallow deer involves episodic secretion of both oxytocin and PGF-2 alpha.

Maternal, umbilical, uterine and amniotic prostaglandin E and F2 alpha levels in labour

This paper confirms the important role played by prostaglandins in the induction of uterine contractions and the initiation of human labour, although the exact mechanism of action in labour remains unclear. Seventeen pregnant women at term were studied. Of these nine were in labour and the remainder underwent elective section. Prostaglandin E and F2 alpha levels were measured in maternal, umbilical and uterine plasma and amniotic fluid by radioimmunoassay. Levels of prostaglandin E were generally higher than prostaglandin F2 alpha but they were significantly lower in maternal and uterine plasma. Levels of prostaglandin F2 alpha were significantly higher in maternal plasma during labour. The highest levels of prostaglandin were found in amniotic fluid. Measurements indicate that the decreasing ratio of prostaglandin E/F2 alpha is more important in the initiation of labour than absolute levels of either prostaglandin.

Plasma elevations of histamine and a prostaglandin metabolite in acute asthma

Recent studies of laboratory-provoked asthma have suggested that asthma is an inflammatory disease of lower airways. The purpose of this study was to measure the systemic elaboration of 2 bronchoconstrictive inflammatory mediators during naturally acquired acute asthma utilizing a prospective, serial-sampling protocol. Plasma levels of 13,14-dihydro-15-keto-PGF2 alpha and histamine were measured by radioimmunoassay and radioenzymatic assay, respectively, in 23 children with acute asthma. Mean PG metabolite and histamine values (pg/ml) before (167 +/- 72, 1,029 +/- 378) and 10 to 90 min after (377 +/- 145, 1,000 +/- 489) initial therapy were significantly higher than those of the same children after resolution of asthma (2.9 +/- 0.2, 260 +/- 42) and those of normal children (4.3 +/- 0.9, 240 +/- 14). Peak PG metabolite levels were significantly higher in children who presented with PEFR values (% predicted) less than 40% (1,234 +/- 432) compared with those who presented with greater than 40% (404 +/- 296), and in children with post-therapy improvement in PEFR of less than 20% (1,281 +/- 470) compared with those with greater than 20% (365 +/- 226). Histamine levels were significantly higher in children with post-therapy improvement in PEFR of less than 20% (2,560 +/- 1,600) compared with those with greater than 20% (475 +/- 100), and in hospitalized (3,915 +/- 1,910) compared with nonhospitalized (408 +/- 130) children. Significant differences were not observed on the basis of corticosteroid dependence, allergic disposition, or type of initial therapy. These data suggest a role for histamine and PGF2 alpha in the pathogenesis of airway inflammation in acute asthma.

Levels of 15-keto-13,14-dihydro-PFG2 alpha, progesterone and oestradiol-17 beta after induced ovulations in llamas and alpacas

Six llamas and 6 alpacas were mated to vasectomized males; ovulation and corpus luteum formation followed. Progesterone in blood was elevated from day 5 and reached maximum concentrations of 10–20 nmol/1 on day 7–8. A rapid decline in progesterone levels occurred on day 9–10 in connection with repeated surge releases of prostaglandin F_2α. Oestradiol-17β levels were > 100–200 pmol/1 during oestrus when the animals were mated. These high levels might have been caused by coital stimulation. A temporary increase was detected in connection with the rise in progesterone levels in the early luteal phase. With this exception levels of oestradiol stayed low, 20–40 pmol/1 during the luteal phase but rose in most animals after luteolysis to 40–60 pmol/1.

Arachidonic acid metabolites and their circadian rhythm in patients with allergic bronchial asthma

The aim of this study was to investigate circadian variation in concentrations of arachidonic acid (AA) metabolites in relation to the circadian pattern in bronchial patency. Blood samples were obtained at 4-hr intervals from 2000 of 1 day until 1400 of the next from 12 diurnally active asthmatic and six diurnally active non-asthmatic patients. Bloods were analyzed for the prostanoids thromboxane A2 (measured as stable metabolite 6-keto-PGF1a), PGE2 and PGF2a. Airways patency was assessed by self-measurement of peak expiratory flow (PEF). In asthmatics, circadian variation was detected in PEF as well as PGE2 and TXB2. The circadian trough of the PEF rhythm closely coincided with the circadian peak of the PGE2 and TXB2 rhythms. In the controls, the PEF was not circadian rhythmic. Of the AA metabolites only 6-keto-PGF1a exhibited 24-hr bioperiodicity in the controls. The controls exhibited a significantly higher circadian mean of PEF (P less than 0.001), while the asthmatics had a lower 24-hr average PGE2 but greater mean TXB2/PGE2 ratio. The obstructive effect caused by the overall 24-hr deficiency of PGE2 in asthmatics is possibly amplified by the increased of TXB2 during the early morning hours. This dissociation of the temporal patterns in TXB2 and PGE2 levels over the 24 hr is discussed as a characteristic finding for asthmatics.