Prostaglandin F and progesterone secretion by porcine endometrium and corpus luteum in vitro

Slices of porcine endometrium and corpus luteum tissue obtained from mature sows throughout the luteal phase of the oestrous cycle were incubated in culture medium which was analysed at regular intervals over a period of 8 hours for prostaglandin F and progesterone. Prostaglandin F secretion was greatest by endometrium obtained during the mid III to late I luteal stage of the cycle and the increased levels secreted by this tissue were paralleled by high levels of secretion from corpus luteum tissue. The addition of indomethacin (10 μg/ml) to the culture medium completely abolished prostaglandin F secretion by both endometrium and luteal tissue indicating that the high levels of the prostaglandin were due to synthesis. Progesterone secretion by the corpus luteum was maximal from early luteal tissue and had declined to considerably lower levels by late stage tissue when prostaglandin secretion was greatest. The possible physiological significance of luteal prostaglandin F secretion is discussed.     

Rat renal medulla possess high capacity to catabolize prostaglandins

Prostaglandin E2 is converted to 15-keto-13,14 dihydro prostaglandin E2,15-keto-prostaglandin F2 alpha and 15-keto-13,14 dihydro prostaglandin F2 alpha, by supernatants from rat kidney medulla. The main pathway for prostaglandin E2 inactivation is the combined action of 15 hydroxy dehydrogenase and delta 13 reductase enzymes. 9-Keto-reductase route constitutes a minor pathway. Prostaglandin F2 alpha is converted into 15-keto-prostaglandin F2 alpha, 15-keto-13, 14 dihydro prostaglandin F2 alpha and 15-keto-dihydro prostaglandin E2. Enzyme activities are time and substrate-concentration dependent. In the presence of an excess of substrate, rat renal medulla inactivates 40 and 56 times more prostaglandin E2 and prostaglandin F2 alpha, respectively, than the amount which is released under basal conditions. These results are in contrast to the generally accepted concept that the kidney cortex is the sole site of renal prostaglandin catabolism, and suggest, for the first time, that rat renal medulla may be a key site for the modulation of prostaglandin levels in the kidney.     

Prostaglandin F in monkey uterine fluid during the menstrual cycle and following steroid treatment

Prostaglandin F levels were determined in monkey uterine fluid collected daily from a silicone tubing collection system surgically installed in adult female rhesus monkeys. Sampling was obtained from intact and ovariectomized — hormone treated monkeys. During the primate menstrual cycle, uterine fluid prostaglandin F levels showed a cyclic pattern in concentration with highest values recorded during the 18–20th day of the cycle. Estrogen treatment to the ovariectomized female elicited a striking and marked increase in uterine fluid prostaglandin F levels while progesterone treatment had little effect. These results suggest that the presence of uterine fluid prostaglandin F is estrogen dependent and may be causely related to the control of menstrual cyclicity.     

Prostaglandin biosynthesis and catabolism in the developing fetal sheep lung.

The prostaglandin biosynthetic and catabolic capacity of homogenates of lungs from fetal sheep of various gestational ages was measured. Prostaglandin biosynthesis was assayed by the deuterium-isotope dilution technique making use of mass fragmentography whereas prostaglandin catabolism was measured by the radioisotope-dilution method described previous (Pace-Asciak, C.R. and Rangaraj, G. (1976) J. Biol. Chem. 251, 3381-3385). Homogenates of lungs from fetuses of all ages tested (40 days to term) formed both prostaglandins E2 and F2alpha; although prostaglandin F2alpha was formed to a greater extent than prostaglandin E2 by the 40 days lung, prostaglandin E2 increased with increasing age until at term the ratio of both prostaglandins approached unity. Total prostaglandin biosynthesis (E2 + F2alpha) rose gradually with age (approx. 3 fold increase between 40 days and term). Prostaglandin F2alpha catabolism occurred mainly by the prostaglandin 15-hydroxy dehydrogenase pathway; this activity was detectable even at 40 days and remained unchanged up to 80 days. Prostaglandin catabolic activity rose sharply at 90 days (approx. 3 fold) with a maximum around 110 days (approx. 4 fold) decreasing back to 40 day levels by term (143 days). The increasing prostaglandin catabolic activity around 90-100 days in this species is discussed in relation to the hemodynamic changes in the lungs starting around this age and the appearance of surfactant. Prostaglandin catabolism might play an important role in the developing organ controlling steady state concentrations of prostaglandins during certain periods of organogenesis.     

PGE2 and PGF2 alpha in the nasal lavage fluid from healthy subjects: methodological aspects

Prostaglandins E2 and F2 alpha were estimated in nasal secretions from ten healthy volunteers by high performance liquid chromatography and radioimmunological assay. Prostaglandin concentrations determined in five consecutive nasal washes with saline at room temperature showed that the nasal mucosa was stimulated after instillation. A substantial increase of basal levels was associated with the second nasal lavage. In all volunteers aspirin treatment inhibited prostaglandin release.     

Prostaglandin levels in endometrial jet wash specimens in patients with dysmenorrhea before and after indomethacin therapy

A patient with functional primary dysmenorrhea of over two years duration was subjected to the endometrial jet wash technique during the period of active menstrual flow. Prostaglandin F analysis of the jet washings revealed significantly elevated levels during menstruation over normal control levels. Following indomethacin therapy, jet wash prostaglandin F levels were dramatically reduced and the patient became asymptomatic. A cause and effect relationship between prostaglandin F and dysmenorrhea is suggested by these studies     

Prostaglandin levels in endometrial jet wash specimens in patients with dysmenorrhea before and after indomethacin therapy.

A patient with functional primary dysmenorrhea of over two years duration was subjected to the endometrial jet wash technique during the period of active menstrual flow. Prostaglandin F analysis of the jet washings revealed significantly elevated levels during menstruation over normal control levels. Following indomethacin therapy, jet wash prostaglandin F levels were dramatically reduced and the patient became asymptomatic. A cause and effect relationsship between prostaglandin F and dysmenorrhea is suggested by these studied.     

Effect of prostaglandin F2 alpha at different stages of guinea-pig pregnancy

It is believed that suppression of the processes by which prostaglandin F2 alpha is released from the uterus during the estrous cycle is vital to maintenance of pregnancies in guinea-pigs. Prostaglandin F2 alpha was injected into pregnant guinea-pig at four different stages of gestation to investigate the effect increased prostaglandin might have. The study revealed an alteration in the sensitivity of the pregnancy to prostaglandin F2 alpha as pregnancy progressed. Recovery from the prostaglandin insult was more likely if the injection was given after Day 24 than before Day 18. In some animals the serum progesterone levels fell following the injection and then subsequently recovered. It appears that effects which are potentially hazardous to the pregnancy are countered in a variety of ways.     

Specific production of prostaglandin E by human amnion in vitro

Prostaglandin production by intra-uterine human tissues has been investigated using a method of tissue superfusion. Tissues were obtained at elective Caesarean section and after spontaneous vaginal delivery. It was found that all the tissues studied (amnion, chorion, decidua and placenta) produced more prostaglandin E (PGE) and 13,14-dihydro-15-keto-prostaglandin F (PGFM — the major circulating metabolite of prostaglandin F) than prostaglandin F (PGF). Amnion produced significantly more PGE (but not PGF or PGFM) than any other tissue. Prostaglandin production by each tissue was similar whether it was taken at elective Caesarean section or after spontaneous vaginal delivery.     

Prostaglandin F levels in endometrial jet wash specimens during the normal human menstrual cycle

The Gravlee endometrial jet wash technique has been used to collect uterine fluid in normal human volunteers for Prostaglandin F analysis throughout the human menstrual cycle. Uterine washings so obtained demonstrated a cyclicity in prostaglandin F content with low concentrations found during the proliferative phase and a 3–4 fold rise occurring during the secretory phase. Menstrual fluid prostaglandin F content collected with the jet wash technique gave the highest total concentrations.     

Prostaglandin F levels in endometrial jet wash specimens during the normal human menstrual cycle.

The Gravlee endometrial jet wash technique has been used to collect uterine fluid in normal human volunteers for Prostaglandin F analysis throughout the human menstrual cycle. Uterine washings so obtained demonstrated a cyclicity in prostaglandin F content with low concentrations found during the proliferative phase and a 3-4 fold rise occurring during the secretory phase. Menstrual fluid prostaglandin F content collected with the jet wash technique gave the highest total concentrations.     

Effect of prostaglandin F2alpha on cells of the mammary gland alveoli in mice

In studies on lactating laboratory mice an influence of prostaglandin F2 alpha on the value of transepithelial potential difference and resistance of the alveolar secretory epithelium in the mammary gland, was studied. Prostaglandin F2 alpha did not affect initial level of transepithelial potential difference and resistance in alveoles. In all experiments with the preliminary application of prostaglandin F2 alpha in different concentrations (1 x 10(-5)-1 x 10(-11) M) was registered a reliable increase in an amplitude (before 31 +/- 2%) and duration (before 43 +/- 3%) to return reactions on oxytocin. Prostaglandin F2 alpha caused a reduction of transepithelial resistance in the alveolar secretory epithelium of first phase to return reaction on oxytocin on 28 +/- 22%. The data obtained indicate a possibility of participation of prostaglandin F2 alpha in development of certain stages of shaping a composition of milk.     

Demonstration of a thyrotropin-responsive prostaglandin E2-9-ketoreductase in bovine thyroid.

1. Prostaglandin E2-9-ketoreductase activity was demonstrated in bovine thyroid homogenates. 2. The enzyme requires reduced pyridine nucleotide and dialysis prior to assay for optimal activity. 3. The products of the reaction, NADP and prostaglandin F2alpha, inhibit enzyme activity. 4. Sigmoidal kinetics are observed when substrate concentration is plotted against enzyme velocity, indicative of an allosteric enzyme. 5. Thyrotropin increases enzyme activity in bovine thyroid slices. This increase is both hormone- and tissue-specific.     

Prostaglandin 9-hydroxydehydrogenase activity in the adult rat kidney. Identification, assay, pathway, and some enzyme properties.

Prostaglandin F2alpha is converted to 15-keto-13,14-dihydroprostaglandin E2 by adult rat kidney homogenates. A variety of substrates labeled as either the 9beta position alone or at several other positions in the prostaglandin molecule were used to define the step at which the crossover from the F type to the E type prostaglandins takes place. Time course studies further confirmed that 15-keto-13,14-dihydroprostaglandin F2alpha is the immediate substrate for this enzyme which we have termed prostaglandin 9-hydroxydehydrogenase. An assay system based on specific loss of tritium from 9beta-tritiated prostaglandin F2alpha is described. Enzyme activity with prostaglandin F2alpha as substrate is linear with time up to 10 min, stimulated by NAD+, saturable at low concentrations of substrate, stable to storage at minus 25 degrees in phosphate buffer (up to 3 weeks), and has a broad pH optimum around 7.5. The product, 15-keto,13,14-dihydroprostaglandin E2 was identified by mass spectrometry through a sodium borohydride-sodium borodeuteride reduction method.     

Uterine vein prostaglandin levels in late pregnant dogs.

We studied the uterine venous plasma concentrations of prostaglandins E2, F2 alpha, 15 keto 13,14 dihydro E2 and 15 keto 13,14 dihydro F2 alpha in late pregnant dogs in order to evaluate the rates of production and metabolism of prostaglandin E2 and F2 alpha in pregnancy in vivo. We used a very specific and sensitive gas chromatography-mass spectrometry assay to measure these prostaglandins. The uterine venous concentrations of prostaglandin E2 and 15 keto 13,14 dihydro E2 were 1.35 +/- .27 ng/ml and 1.89 +/- .37 ng/ml, respectively; however, we could not find any prostaglandin F2 alpha and very little of its plasma metabolite in uterine venous plasma. Since uterine microsomes can generate prostaglandin F2 alpha and E2 from endoperoxides, prostaglandin F2 alpha production in vivo must be regulated through an enzymatic step after endoperoxide formation. Prostaglandin E2 is produced by pregnant canine uterus in quantities high enough to have a biological effect in late pregnancy; however, prostaglandin F2 alpha does not appear to play a role at this stage of pregnancy.     

Determination of prostaglandin F in blood plasma using chemically modified bacteriophage technique

The levels of prostaglandin F found in human and rabbit plasma were determined by the chemically modified bacteriophage assay.Prostaglandin F₂α was coupled covalently to bacteriophage T4 using carbodiimide as cross linking agent and the conjugated phage could be inactivated by anti-prostaglandin F₂α antibodies. Prostaglandins specifically inhibited the modified phage inactivation caused by antiserum and as little as 200 picograms of prostaglandin F₂α could be detected by this system. Anti-prostaglandin F₂α antibodies had a high specificity toward prostaglandin F₂α and exhibited a very low degree of cross reaction to the other prostaglandin derivatives. The concentration of the extracted prostaglandin F₂α from the plasma containing exogenous prostaglandin F₂α could be determined with a high recovery.In normal human males and in male rabbits, 0.300.82 and 0.421.22 nanograms of prostaglandin F per ml of plasma were found, respectively. These levels of prostaglandin F in plasma agree with those determined by the radioimmunoassay.     

Concentrations of prostaglandin E2 and F2 alpha in the cardiovascular system of infants with persisting patent ductus arteriosus

The distribution of prostaglandin E2 and F2 alpha was examined in the peripheral veins and in several positions of the cardiovascular system before and after the blood had passed through the lungs in 37 infants. Prostaglandin E2 varied from 0.25 +/- 0.09 ng/ml to 0.44 +/- 0.09 ng/ml when measured in the pulmonary artery, the ductus arteriosus, the right atrium, the right ventricle, the left atrium, the left ventricle, the inferior vena cava and the descending aorta. Prostaglandin F2 alpha was much higher in these positions of the cardiovascular system. The range was 0.99 +/- 0.36 ng/ml to greater than 2.0 ng/ml. The vascular tissues produced virtually identical high amounts of prostaglandin E2 and F2 alpha, but there were no significant differences in prostaglandin E2 and F2 alpha, concentrations, in venous blood as well as in systemic arterial blood. The results suggest that prostaglandin E2 is not responsible for the persisting patency of the ductus arteriosus in infants. There is no explanation for the increased prostaglandin F2 alpha concentrations in these patients.     

Prostaglandins in the human fetal circulation in mid-trimester and term pregnancy

Concentrations of prostaglandins in fetal and maternal plasma during mid-pregnancy and fetal plasma at term have been measured. Fetal levels at both gestations were higher than found in maternal blood. The stable chemical breakdown product of prostacyclin, 6-keto-prostaglandin F_1∝, was consistently considerably higher in the fetus during mid-pregnancy compared with at term. Prostaglandin F levels were also significantly higher in mid-pregnancy, though there was no difference in the concentrations of the major circulating prostaglandin F metabolite, PGFM. Concentrations of prostaglandin E were similar at the two stages of pregnancy. The physiological significance of these findings is discussed.     

Prostaglandin production by type II alveolar epithelial cells.

Prostaglandin production was studied in fetal and adult type II alveolar epithelial cells. Two culture systems were employed, fetal rat lung organotypic cultures consisting of fetal type II cells and monolayer cultures of adult lung type II cells. Dexamethasone, thyroxine, prolactin and insulin, hormones which influence lung development, each reduced the production of prostaglandin E and F alpha by the organotypic cultures. The fetal cultures produced relatively large quantities of prostaglandin E and F alpha and smaller quantities of 6-keto-prostaglandin F1 alpha and thromboxane B2. However, prostaglandin E2 production was predominant. In contrast, the adult type II cells in monolayer culture produced predominantly prostacyclin (6-keto-prostaglandin F1 alpha) along with smaller quantities of prostaglandin E2 and F2 alpha. The type II cells were relatively unresponsive to prostaglandins. Exogenously added prostaglandin E, had no effect on cell growth, and only a minimal effect on cyclic AMP levels in the monolayer cultures.     

Plasma concentrations of 9-deoxo-16,16-dimethyl-9-methylene-PGE2 in Rhesus monkeys after administration by various routes

A method is described for the estimation of 9-deoxo-16,16-dimethyl-9-methylene-PGE₂ by double antibody radioimmunoassay. Plasma samples obtained from animals treated with 9-methylene-16,16-dimethyl-PGE₂,1-adamantanamine salt were extracted with diethyl ether to recover the prostaglandin. The validation of sample preparation and assay procedure are presented. Rhesus females were treated by several routes of administration and the samples assayed for drug content. Maximum blood levels were probably reached 30 minutes following subcutaneous injection and within 30 seconds of an intravenous injection. Results of the acute intravenous injection indicate an initial half-life of approximately one minute in peripheral circulation. Continuous intravenous infusion at 3 increasing doses of this compound resulted in a stepwise increase in plasma drug concentrations. Vaginal administration of 9-methylene-16,16-dimethyl-PGE₂,1-adamantanamine salt in suppositories produced a dose dependent increase in plasma drug concentration. Higher plasma drug concentrations were produced when the prostaglandin was delivered in H-15 base suppositories than in E-76 base suppositories.