Prostaglandin F2alpha added to extended boar semen at processing elicits in vitro myometrial contractility after 72 hours of storage.

Improved fertility will maximize productivity of the swine industry. Myometrial contractility is an essential component in the fertilization process because it is the mechanism by which spermatozoa are transported to the site of fertilization. In the present study, we evaluated the potential use of PGF2alpha supplementation to the extended pig semen in regard to inducing myometrial contractility of sows. Extended boar semen (80 mL) was supplemented with PGF2alpha (5 mg) for 72 h at 17 +/- 1 degrees C. Cumulative doses of 0.1, 1, 10 and 100 microL of the mixture were tested on uterine strips obtained from diestrus sows. An increase in myometrial contractility was recorded with PGF2alpha supplementation when compared to extended semen or extender treatment alone after 72 h of incubation. Addition of PGF2alpha to the extended boar semen at the time of the experiment did not differ from the 72 h treated group. The results from this study support that PGF2alpha preparations can be added to extended doses of boar semen at processing to enhance myometrial contractility at the time of insemination for up to 72 h.     

Motility characteristics of boar spermatozoa after addition of prostaglandin F2alpha

Addition of prostaglandin F2alpha (PGF2alpha) to extended boar semen has been shown to slightly increase reproductive parameters in sows such as the conception rate and the total number of piglets born alive. The mechanisms by which PGF2alpha affect these parameters have not yet been elucidated, but it is possible that the sperm transport after insemination is increased. This study investigated whether the sperm motility from 20 Piétrain boars improved when PGF2alpha (Dinolytic; 5 mg PGF2alpha/ml) was added to diluted semen. Different amounts of PGF2alpha (0, 0.5, 1 and 2 ml/100 ml) were tested and the motility was evaluated immediately after addition of PGF2alpha, after 30 min, 2 h, and 24 h. Two computer-assisted semen analysis (CASA) systems, namely the Sperm Quality Analyzer (SQA-IIC) and the Hamilton Thorne (HTR Ceros 12.1) were used to assess the motility parameters. With the SQA-IIC, sperm motility index values of the treated groups were only slightly higher (P>0.05) compared to the negative control group. The different motility parameters measured with the HTR Ceros 12.1 were similar between the treatment groups, except for beat cross frequency, which was higher in the control group (1.5-5%; P<0.001). This study documented that the addition of 2.5, 5 or 10 mg PGF2alpha to 100 ml diluted boar sperm does not increase any sperm motility parameter. Further research is necessary to elucidate mechanisms by which PGF2alpha in diluted semen may improve the reproductive performance in swine farms.     

Effect of dexcloprostenol on endogenous prostaglandin F2alpha release in dairy heifers

Cloprostenol was previously believed to be unable to release endogenous prostaglandin F2alpha (PGF2alpha) when administered during early bovine diestrus. A prostaglandin release is, however, seen in late diestrus. The aim of this study is to find out whether dexcloprostoenol (containing the only biologically active isomer, d-isomer, of cloprostenol) induces endogenous PGF2alpha release during early and late diestrus. Twelve heifers of the Finnish Ayrshire breed were allocated into two equal groups. Their estrous cycles were synchronized with dexcloprostenol. A further luteolysis was induced with 0.15 mg of dexcloprostenol either on Day 7 (group D7 or early diestrus) or on Day 14 (group D14 or late diestrus) after ovulation. Blood for progesterone and the PGF2alpha metabolite 15-ketodihydro-PGF2alpha determinations was collected immediately before dexcloprostenol treatment and thereafter every second hour for 48 h. Five of the six heifers in both groups showed significantly increased blood levels of 15-ketodihydro-PGF2alpha at some time during the 48-h experimental period. The intervals from treatment to the first significant increases of the PGF2alpha metabolite were 32.8+/-2.3 h (min. 30 h, max. 36 h) and 20.0+/-4.2 h (min. 14 h, max. 24 h) in groups D7 and D14, respectively (P < 0.01). We have concluded that dexcloprostenol induced endogenous PGF2alpha release in most cases, regardless the time of its administration (early or late diestrus). This release, however, differs from that observed during spontaneous luteolysis.     

Estrogens and prostaglandin F2alpha in the semen and blood plasma of stallions

A study was performed to determine the levels of estrogens and prostaglandin F(2)alpha in the stallion ejaculate. Simultaneous semen and blood plasma samples were collected from 19 stallions, 2 weeks apart, during the breeding season. Although not statistically different, the total mean estrogen content tended to be higher in seminal plasma (4447 pg/ml) than in blood (2497 pg/ml). A tendency was found for higher mean estrone sulphate concentrations than for total free steroid in both seminal (4116.1 vs 330.5 pg/ml) and blood plasma (2447.1 vs 49.5 pm/ml). Mean concentrations of estrone in ejaculate and blood plasma were 257.1 +/- 267.0 (SD) and 9.5 +/- 5.4 pg/ml, respectively. Estradiol-17beta concentrations were 73.4 +/- 87.4 and 40.0 +/- 27.6 pg/ml in ejaculates and blood plasma, respectively. Mean PGF(2)alpha concentrations tended to be much higher than total estrogens (1106.8 +/- 1636.4, SD, vs approximately 260 ng/ejaculate, respectively). To our knowledge this is the first report of PGF(2)alpha and estrogen concentrations in the stallion ejaculate.     

Boar spermatozoa and prostaglandin F2alpha. Quality of boar sperm after the addition of prostaglandin F2alpha to the short-term extender over cooling time

Prostaglandin F(2alpha) (PGF(2alpha)) has been used to improve reproductive performance in swine. The goal of the present work was to determine how the addition of PGF(2alpha) affects boar sperm quality. Eleven different treatments were evaluated: eight with only PGF(2alpha) (0.625, 1.25, 2.50, 5, 10, 12.50, 25 and 50mg PGF(2alpha)/100ml) and three binary treatments (0.625mg PGF(2alpha)/100ml+200mug/ml hyaluronic acid (HA), 1.25mg PGF(2alpha)/100ml+200mug/ml HA, 0.625mg PGF(2alpha)/100ml+7.5muM caffeine (Caf)). All these substances were added to 16 ejaculates from 16 healthy and sexually mature boars (n=16), and each ejaculate was considered as a replicate. Our study also assessed the effects of these 11 treatments over different periods of preservation. Sperm quality was tested immediately after the addition of treatments (time 0), and after 1, 3, 6 and 10 days of cooling at 15 degrees C. To evaluate sperm quality, five parameters were analysed: (1) sperm viability, acrosome and mitochondrial sheath integrity (using a multiple fluorochrome-staining test), (2) sperm motility, (3) sperm morphology and (4) agglutination (using a computer assisted system) and (5) osmotic resistance (using the ORT). Parametric (analysis of variance for repeated measures) and non-parametric tests (Friedman test) were used as statistical analyses. Treatments with PGF(2alpha) concentrations higher than 12.5mg/100ml were cytotoxic while the others did not damage boar spermatozoa. Thus, the other treatments may be used to produce profitable effects without adverse effects. Moreover, the addition of PGF(2alpha) at 5mg/100ml to sperm diluted in BTS may maintain sperm viability and motility better after 6 days of cooling, because significant differences were observed (P<0.05) compared with control at the same time.     

Effect of exogenous progesterone on prostaglandin F2 alpha release and the interestrous interval in the bovine

The present study was developed to determine if administration of progesterone, early in the estrous cycle of the cow, stimulated an advanced pulsatile release of PGF2 alpha from the uterine endometrium resulting in a decreased interestrous interval. Twenty-three cyclic beef cows were randomly assigned to receive either sesame oil or progesterone (100 mg) on Day 1, 2, 3 and 4 of the estrous cycle. Peripheral plasma concentrations of progesterone and the metabolite of prostaglandin F2 alpha, 15-keto-13,14-dihydro-prostaglandin F2 alpha (PGFM) were measured by radioimmunoassay. Administration of exogenous progesterone increased peripheral plasma concentration of progesterone in treated (3.67 ng/ml) compared to control (1.28 ng/ml) cows from Day 2 through 5 of the estrous cycle. Progesterone administration shortened the interestrous interval (16.7 d) compared to controls (21.6 d). The shortened interestrous intervals in treated cows resulted from an earlier decline in peripheral plasma progesterone. Decline of peripheral plasma progesterone concentrations is coincident with an increased pulsatile release of PGFM in both progesterone treated and control cows. Results indicate that administration of exogenous progesterone stimulates an earlier maturation of endometrial development, causing an advanced release of PGF2 alpha which shortens the interestrous interval of the cow.     

The effect of prostaglandin F2 alpha on third stage labor.

The effects of intramyometrially injected PGF2 alpha intravenous Ergometrin and no treatment were compared during 3rd stage labor in 140 patients. In comparison with Ergometrin or no treatment, PGF2 alpha significantly reduced the duration of 3rd stage labor, blood loss, incidence of subinvolution and subfebrility.     

Urinary excretion of prostaglandin E2 and prostaglandin F2alpha in potassium-deficient rats

Potassium-deficiency was induced in rats by dietary deprivation of potassium. The animals became polyuric and urine osmolality decreased more then three-fold compared to controls. Urinary excretion of prostaglandin E2 (PGE2) and prostaglandin F2alpha (PGF2alpha) did not increase during 2 weeks of potassium depletion. Partial inhibition of renal prostaglandin synthesis by meclofenamate did not increase the urine osmolality after water deprivation. These results make unlikely the hypothesis that the polyuria of potassium-deficiency, is the result of enhanced renal synthesis of prostaglandins with subsequent antagonism of the hydro-osmotic effect of vasopressin. Male animals consistently excreted less PGE2 than female animals.     

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.     

Effects of indomethacin, prostaglandin E2, prostaglandin F2 alpha and 6-keto-prostaglandin F1 alpha on hatching of mouse blastocysts

The present study has been performed to investigate how PGs would participate the hatching process. Effects of indomethacin, an antagonist to PGs biosynthesis, on the hatching of mouse blastocysts were examined in vitro. Furthermore, it was studied that prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha) or 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were added to the culture media with indomethacin. The hatching was inhibited by indomethacin yet the inhibition was reversible. In the groups with indomethacin and PGE2, no improvement was seen in the inhibition of hatching and the inhibition was irreversible. In the groups with indomethacin and PGF2 alpha, inhibition of hatching was improved in comparison with the group with indomethacin. In the groups with indomethacin and 6-keto-PGF1 alpha, no improvement was seen. The above results indicated that PGF2 alpha possibly had an accelerating effect on hatching and a high concentration of PGE2 would exert cytotoxic effect on blastocysts.     

Concentrations of endogenous free amino acids in rabbit reticulocyte lysates and the effect of incubation

Amino acid analyses show that while the free amino acids found in the rabbit reticulocyte translation system do not increase during nuclease treatment or during prolonged storage, the endogenous levels of many amino acids are so high that the choice of a radioactive; precursor for a translation should be based not only on the abundance of the amino acid in the translation product but also on its concentration in the lysate preparation. It is shown that the variation of amino acid concentrations between different lysates is sufficiently small to allow one to use the concentrations reported in this study to calculate the amount of radioactive amino acid necessary for satisfactory incorporation.     

The effect of prostaglandin F2 alpha administration on progesterone after hysterectomy of guinea-pigs

It is believed that in guinea-pigs the main luteolytic agent is prostaglandin F2 alpha (PGF2a) and that it is synthesised in the uterus. In this study non-pregnant guinea-pigs were hysterectomised at Day 5 of the estrous cycle. Peripheral progesterone levels in animals from which the uterus had been removed remained elevated for an extended time. The results suggested the corpora lutea (CL) had an inherent life span in excess of the length of the estrous cycle. However after a time the levels of circulating progesterone declined, suggesting there might have been a reduction of a stimulating factor or the appearance of a non-uterine luteolysin. If after hysterectomy PGF2a was administered 4 and 5 days later then there was a reduction in the mean progesterone level but the decline did not continue. The CL at the stage of the experimental procedure were sensitive to luteolysin but they had retained their capability to resist endocrinological insult. The study provided further support for the contention that control of PGF2a activity is vital for progesterone maintenance. Additionally, the cells of the CL have the potential to be the site of some of the PGF2a control.     

The effect of prostaglandin F2 alpha administration on progesterone after hysterectomy of guinea-pigs

It is believed that in guinea-pigs the main luteolytic agent is prostaglandin F2 alpha (PGF2a)_and that it is synthesised in the uterus. In this study non-pregnant guinea-pigs were hysterectomised at Day 5 of the estrous cycle. Peripheral progesterone levels in animals from which the uterus had been removed remained elevated for an extended time. The results suggested the corpora lutea (CL) had an inherent life span in excess of the length of the estrous cycle. However after a time the levels of circulating progesterone declined, suggesting there might have been a reduction of a stimulating factor or the appearance of a non-uterine luteolysin. If after hysterectomy PGF2a was administered 4 and 5 days later then there was a reduction in the mean progesterone level but the decline did not continue. The CL at the stage of the experimental procedure were sensitive to luteolysin but they had retained their capability to resist endocrinological insult. The study provided further support for the contention that control of PGF2a activity is vital for progesterone maintenance. Additionally, the cells of the CL have the potential to be the site of some of the PGF2a control.     

Effect of prostaglandin F3 alpha on gastric mucosal injury by ethanol in rats: comparison with prostaglandin F2 alpha

In humans eicosapentaenoic acid can be converted to 3-series prostaglandins (PGF3 alpha, PGI3, and PGE3). Whether 3-series prostaglandins can protect the gastric mucosa from injury as effectively as their 2-series analogs is unknown. Therefore, we compared the protective effects of PGF3 alpha and PGF2 alpha against gross and microscopic gastric mucosal injury in rats. Animals received a subcutaneous injection of either PGF3 alpha or PGF2 alpha in doses ranging from 0 (vehicle) to 16.8 mumol/kg and 30 min later they received intragastric administration of 1 ml of absolute ethanol. Whether mucosal injury was assessed 60 min or 5 min after ethanol, PGF3 alpha was significantly less protective against ethanol-induced damage than PGF2 alpha. These findings indicate that the presence of a third double bond in the prostaglandin F molecule between carbons 17 and 18 markedly reduces the protective effects of this prostaglandin on the gastric mucosa.     

Histophysiological studies of prostaglandin F2alpha on isolated organs. I. Effect of prostaglandin F2alpha on the heart.

The physiological and histochemical effects of PGF2alpha on isolated rabbit hearts were examined. The results showed a positive inotropic effect. The coronary flow increased. From the histochemical studies, adenosine triphosphatase (ATP-ase) and succinic dehydrogenase activities were increased while that of alkaline phosphatase was decreased. Glycogen granules were depleted. These findings were discussed on a histophysiological basis.     

Role of prostaglandin F2alpha in ovulation.

Using radioimmunoassay procedures, the levels of plasma, uterine and ovarian prostaglandin (PG) F2alpha, and those of plasma estradiol and progesterone were measured in intact, hysterectomized or ovariectomized immature female rats pretreated with PMS and subsequent HCG. Occurrence of ovulation was confirmed at 8 hours after the HCG administration not only in the intact rats but also in the hysterectomzied rats. The levels of plasma estradiol and progesterone, and of uterine and ovarian PGF2alpha rose with the PMS injection alone, but they did not reach the peaks before the HCG administration. Both plasma estradiol and uterine PGF2alpha showed a peak at 2 hours after the HCG injection. These peaks were antecedent 2 or 6 hours before the peaks of ovarian and plasma PGF2alpha, respectively. However, such increase of uterine PGF2alpha does not seem to be indispensable for ovulation, because ovulation could occur in the hysterectomized rats. The levels of ovarian PGF2alpha showed a high plateau from 4 to 8 hours after the HCG injection, and then rapidly decreased after ovulation. The levels of plasma PGF2alpha peaked not only in the intact rats but also in the hysterectomized rats at 8 hours after the HCG treatment. But in the ovariectomized rats, this plasma PGF2alpha peak at 8 hours disappeared and there was no statistical change of plasma PGF2alpha throughout the PMS-HCG treatment. Plasma progesterone gradually increased and reached the maximum at 10 hours after the HCG injection. These results conclude that the main source of increased plasma PGF2alpha during the ovulatory process induced with the PMS-HCG treatment is the ovary, and it is strongly suggested that a rapid increase of PGF2alpha in the ovary may play some important role(s) in the ovulatory process.     

Interactions between exogenous luteinizing hormone (hCG), prolactin and prostaglandin F2 alpha on serum enzymes in the rat

The effect of exogenous luteinizing hormone (hCG), prolactin and prostaglandin F2 alpha, separately or in combination, on the activities of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in rat serum was studied. The changes of enzyme activities varied with the different hormones. Luteinizing hormone hCG and prolactin acted synergistically or antagonistically, depending on the enzyme response. Prostaglandin F2 alpha did not seem to modulate the effect of luteinizing hormone (hCG).     

Characteristics of the normal gluconeogenesis effect of prostaglandin F2 alpha and in myocardial infarct

The effect of PGF2 alpha on glucose synthesis de novo in a healthy rat organism and those with coronary occlusion-myocardial infarction was studied. There was observed prostaglandin's metabolic action simultaneously at one direction: there was increased the concentration of non-nitric precursors of gluconeogenesis in blood of animals of both groups, final disintegration product of tissue proteins, the gluconeogenic activity of key enzymes and therefore the concentration of newly formed glucose went up as so as glycogen in liver, cardiac and skeletal muscle. Seemingly, PGF2 alpha stimulates the intensity not only of gluco-, but glyconeogenesis having cardioprotective action. At the same time metabolic effect of PGF2 alpha is strongly marked in coronary occlusion rat with myocardial infarction.