Reduced platelet aggregation in women after intercourse: a possible role for the cyclooxygenase pathway.

We hypothesise that molecules in the cyclooxygenase pathway affect platelet activity when seminal fluid (SF) is present. We considered the influence of SF on platelet aggregation in women, and believe that the prostanoids in SF signalling are significant. Thirty-one female subjects were studied, 20 of whom were sexually active. Male partners were given either aspirin or indomethacin to inhibit cyclooxygenase. The 6-keto prostaglandin F1α (6-keto PGF1α) and prostaglandin E metabolite (PGE-M) in SF were measured by competitive assay. Platelets and prostanoids were evaluated in women, periodically, before and after intercourse. The platelets were tested with adenosine diphosphate (ADP) and arachidonic acid (AA). To block the interaction between the uterus and SF, some couples used condoms. We found that the 6-keto prostaglandin F1α in urine at 2 hours post-intercourse (1418.75 pg/mL, Std 688.39) was greater than pre-intercourse (772.68 pg/mL, Std 116.54). Post-intercourse, a transient decrease in platelet aggregation was observed in women whose partners did not use condoms. Averages for platelet aggregation were 20.16% with ADP, and more significantly, 37.79% with AA after 2 hours. In contrast, couples using condoms showed no changes, averaging 64.02% with ADP and 72.06% with AA. Women whose partners were taking aspirin or indomethacin also showed no changes. SF from men taking aspirin or indomethacin led to no reduction in platelet aggregometry in their partners. These results indicate that in cases of exposure to SF, the transient change in women's platelet activity could be related to the cyclooxygenase pathway.

Pentoxifylline protects against endotoxin-induced acute renal failure in mice.

Acute renal failure (ARF) in septic patients drastically increases the mortality to 50-80%. Sepsis induces several proinflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha), a major pathogenetic factor in septic ARF. Pentoxifylline has several functions including downregulation of TNF-alpha and endothelia-dependent vascular relaxation. We hypothesized that pentoxifylline may afford renal protection during endotoxemia either by downregulating TNF-alpha and/or by improving endothelial function. In wild-type mice, pentoxifylline protected against the fall in glomerular filtration rate (GFR; 105.2 +/- 6.6 vs. 50.2 +/- 6.6 microl/min, P < 0.01) at 16 h of LPS administration (2.5 mg/kg ip). This renal protective effect of pentoxifylline was associated with an inhibition of the rise in serum TNF-alpha (1.00 +/- 0.55 vs. 7.02 +/- 2.40 pg/ml, P < 0.05) and serum IL-1beta (31.3 +/- 3.6 vs. 53.3 +/- 5.9 pg/ml, P < 0.01) induced by LPS. Pentoxifylline also reversed the LPS-related increase in renal iNOS and ICAM-1 and rise in serum nitric oxide (NO). Enhanced red blood cell deformability by pentoxifylline may have increased shear rate and upregulated eNOS. Studies were therefore performed in eNOS knockout mice. The renal protection against endotoxemia with pentoxifylline was again observed as assessed by GFR (119.8 +/- 18.0 vs. 44.5 +/- 16.2 microl/min, P < 0.05) and renal blood flow (0.86 +/- 0.08 vs. 0.59 +/- 0.05 ml/min, P < 0.05). Renal vascular resistance significantly decreased with the pentoxifylline (91.0 +/- 5.8 vs. 178.0 +/- 7.6 mmHg.ml(-1).min(-1), P < 0.01). Thus pentoxifylline, an FDA-approved drug, protects against endotoxemia-related ARF and involves a decrease in serum TNF-alpha, IL-1beta, and NO as well as a decrease in renal iNOS and ICAM-1.

Endocrine and clinical effects of exemestane (PNU 155971), a novel steroidal aromatase inhibitor, in postmenopausal breast cancer patients: a phase I study.

Clinical and endocrinological effects of exemestane (6-methylenandrosta-1,4-diene-3,17-dione; PNU 155971) were evaluated in an open Phase I study. Thirteen postmenopausal women suffering from advanced breast cancer received exemestane in escalating doses over a 12-week period. Starting on 5 mg once daily (o.d.), exemestane was subsequently escalated at 2-week intervals to 10, 25, 50, 100, and 200 mg o.d. Each patient subsequently continued treatment on the highest tolerated dose until time of progression. One patient terminated treatment after 6 days due to diarrhea that was probably not related to drug therapy, although a relationship could not be excluded. Apart from this, no serious side effects were seen during the dose escalation period. Exemestane (10 mg o.d.) caused maximal suppression of plasma estradiol (E2) and estrone (E1) to a mean of 14.6 and 5.8% of pretreatment levels, respectively, whereas 25 mg of exemestane o.d. suppressed estrone sulfate (E1S) to 8.9% of pretreatment levels. No fall in adrenal steroid levels was recorded. Exemestane (5 mg o.d.) suppressed urinary E2 and E1 to a mean of 11.9 and 12.2% of pretreatment levels, respectively. Administering exemestane at doses of 50-200 mg o.d. caused no further suppression of urinary E1, whereas urinary E2 fell to 6-7% of pretreatment levels. Median time to progression was 63 weeks. We conclude that exemestane is a well-tolerated aromatase inhibitor that effectively suppresses plasma and urinary estrogens in postmenopausal patients with breast cancer.

Analysis of leukotrienes, prostaglandins, thromboxane B2 and their metabolites by capillary isotachophoresis.

An analytical capillary isotachophoretic method for the analysis of the eicosanoids leukotriene E4, leukotriene B4, prostaglandins E1 and E2, 6-keto-prostaglandin F1 alpha, thromboxane B2, and their metabolites of omega- and/or beta-oxidation is described. The method is based on anionic separation and detection by UV absorbance (254 nm) and conductivity and allows simultaneous analysis of the primary compounds and their corresponding major urinary metabolites. The method was applicable to the qualitative and quantitative analysis of prostaglandin E1 in a drug preparation.

PGE1 compared to PGE2/PGF2 alpha ratio as a marker for seminal fluid contamination of urine in studies of renal prostaglandin biosynthesis.

Occasional and unpredictable seminal plasma leakage (SPL) into the urinary system severely limits the usefulness of primary prostaglandin (PG) excretion rates as markers of renal synthesis in male subjects. Although reports to this effect appeared first some 10 years ago, no specific study has been done to define the magnitude of the problem, while several investigators persisted in the use of primary PG excretion rates, disregarding SPL as a confounding factor. We conducted a systematic study with a group of 5 healthy adult subjects who collected 24-h urine with an average frequency of one collection every other week for a total of 20 weeks. 35% of the urine collected contained seminal plasma. It is imperative to be able to disqualify compromised urine specimens in biological studies. With this objective in mind, we developed a method to identify contaminated samples based on the presence of PGE1. This is a major prostanoid in seminal plasma but is normally absent in 'clear' urine.

Resistance of the renal biosynthesis of prostaglandin E2 to the inhibitory effect of indomethacin in the rat in vivo.

Our recent observation that the chronic administration of indomethacin (3.0 mg.kg-1.day) to hypertensive rats, while profoundly inhibiting the urinary excretion of 6-oxo-PGF1 alpha, dinor-6-oxo-PGF1 alpha and thromboxane B2, failed to reduce the urinary levels of PGE2, prompted us to study in more details the influence of indomethacin and of meclofenamate on the urinary excretion of prostaglandins in normal rats. A dose of 1.5 mg.kg-1 of indomethacin administered intraperitoneally was sufficient to cause a 70-75% reduction in the urinary excretion of dinor-6-oxo-PGF1 alpha and of 6-oxo-PGF1 alpha for a period of at least 12 hours. Doses of indomethacin lower than 2.5 mg.kg-1.12h beta 1 or a dose of meclofenamate equal to 5 mg.kg-1.12h beta 1 did not influence the urinary excretion of PGE2. Doses of indomethacin equal to or higher than 2.5 mg.kg-1 were needed to obtain a 50% reduction in the urinary levels of PGE2 for a period of 10-14 h. During these experiments, no circadian rhythm for the urinary excretion of 6-oxo-PGF1 alpha and of dinor-6-oxo-PGF1 alpha could be observed whereas the urine volume and the urinary excretion of PGE2 were found to be greater at night than during the day.(ABSTRACT TRUNCATED AT 250 WORDS)

The urinary excretion of prostaglandins E and their corresponding tetranor metabolites by rats fed a diet rich in eicosapentaenoate.

An HPLC method was developed to determine simultaneously in a single analysis prostaglandin E2, prostaglandin E3, tetranor-prostaglandin E1 and delta 17-tetranor-prostaglandin E1 in rat urine. As internal standard omega-nor-prostaglandin E2 was added to the samples at the beginning of the analysis. The assay was applied in feeding experiments in which rats were fed diets with mixtures of (n-6) and (n-3) fatty acids (linoleate, arachidonate, alpha-linolenate and eicosapentaenoate). The level of urinary prostaglandin E2 was not very much affected by the diet and prostaglandin E3 could never be detected in significant amounts. These primary prostaglandins are assumed to reflect prostaglandin biosynthesis in the kidney medulla. Tetranor-prostaglandin E1 is a characteristic urinary metabolite of prostaglandin E2 in the rat; its level increased after feeding arachidonic acid. delta 17-Tetranor-prostaglandin E1 became a major metabolite when the rats received eicosapentaenoic acid. However, we found that the ratio of urinary tetranor-prostaglandin E1/delta 17-tetranor-prostaglandin E1 is not a very reliable measure of the ratio of prostaglandin E2/prostaglandin E3 formed in the body, because prostaglandin E3 is converted to a much greater extent into delta 17-tetranor-prostaglandin E1 than is prostaglandin E2 into tetranor-prostaglandin E1. As a matter of fact, incubations of tissue homogenates of rats resulted always in predominant formation of prostaglandins of the 2-series, even after high eicosapentaenoate diets. We conclude, in agreement with work carried out earlier, that biosynthetic pathways leading to prostaglandins of the 3-series are of minor importance.

Antiulcer prostaglandin misoprostol: single and multiple dose pharmacokinetic profile.

Low misoprostol dose (microgram range), extremely low plasma levels (pg range) of misoprostol acid, and the necessity of using a complex, time consuming, and labor intensive RIA method of analysis make it technically difficult to study the pharmacokinetic profile of misoprostol in man. The clinical relevance of the misoprostol pharmacokinetic data should be interpreted with care in view of the combined local and systemic effects of the drug. The studies presented in the present review indicate: Extensive metabolism of misoprostol occurs during and/or prior to gastrointestinal absorption. Several metabolites are formed and no unchanged drug is detected in the plasma or urine. The biologically active metabolite in the plasma is misoprostol acid (SC-30695), a de-esterified derivative of misoprostol. Absorption of misoprostol and/or misoprostol acid is extremely rapid resulting in peak plasma levels of misoprostol acid in less than 15 minutes. Absorption probably occurs in the stomach. The elimination half-life of misoprostol acid is short (less than 30 minutes). No accumulation of misoprostol acid occurs in plasma following a 400 microgram q12h dosing regimen of misoprostol.

Plasma phospholipid fatty acids and urinary excretion of prostaglandins PGE1 and PGE2 in infants during total parenteral nutrition, with continuous or sequential administration of fat emulsion.

During total parenteral nutrition, using an identical supply of fat emulsion (350 mg/kg/24 hr) to correct essential fatty acid deficiency in children, the efficacy of two methods of administration was studied: continuous over 24 hr, or discontinuous 3 hr/day. At the beginning of the study, all the infants (1-4 months old) had proven essential fatty acid deficiency. After at least 1 month of one of the two nutritional protocols (continuous or discontinuous), plasma phospholipid fatty acid composition and PGE1 and PGE2 urinary excretion were measured. The results obtained indicate better utilization of the fat emulsion when it is administered almost every day, in continuous infusion over 24 hr (1 g/kg/24 hr of Intralipid 20%).

Identification of the major urinary metabolite of prostaglandin E3 in the rat.

[11,12-3H2]Prostaglandin E3 was administered subcutaneously into male Sprague-Dawley rats in doses of 0.4 microgram-10 mg/kg body weight. 40-60% of the administered radioactivity was excreted in the urine. The major metabolite was isolated by solid phase extraction followed by three steps of high-performance liquid chromatography. The structure of the major metabolite (5-11% of the administered radioactivity) was 7 alpha,11 alpha-dihydroxy-5-ketotetranorprosta-9,13-dienoic acid as shown by gas-liquid chromatography-mass spectrometry and by its conversion into 11 alpha-hydroxy-5-ketotetranorprosta-4(8),9, 13-trienoic acid.

Metabolism of 16, 16-dimethyl-trans-delta 2-prostaglandin E1 methyl ester (ONO-802) following intravenous and vaginal administration to pregnant women.

Following iv and vaginal administration of (5,6-3H2)-ONO-802 (5,6-3H2-16, 16-dimethyl-trans-delta 2-prostaglandin E1 methyl ester) the appearance of radiolabeled compounds in plasma and urine were studied in early pregnant patients. Following iv administration, ONO-802 was rapidly hydrolyzed to the free acid which disappeared from plasma with an approximate half-life of 10-15 min. About 50% of the injected amount of compound was excreted in urine during the first 24 hr after injection. The structures of 16 urinary metabolites were determined. These data demonstrated that, following hydrolysis of ONO-802 to the free acid, the latter can undergo beta- and omega-oxidation like other prostaglandin analogs where enzymatic attack of the 15-hydroxyl group has been blocked. Some of the metabolites were excreted as conjugates (sulfates, glucuronides?) and, in two, the oxo group at C-9 had been reduced to a hydroxyl. Following vaginal administration of ONO-802 (1 mg, 60 microCi) in suppository form, radioactivity corresponding to 100-200 pg/ml of ONO-802 equivalents was found in plasma. The profile of metabolites in urine was qualitatively very similar to that after iv injection of (5,6-3H2)-ONO-802. Based on the data on excretion of metabolites in urine it was calculated that 12-28% of the dose administered vaginally was resorbed into the circulation.