Seminal prostaglandins and fertility

Arachidonic Acid Pathways and Male Fertility: A Systematic Review

Arachidonic acid (AA) is a polyunsaturated fatty acid that is involved in male fertility. Human seminal fluid contains different prostaglandins: PGE (PGE₁ and PGE₂), PGF_2α, and their specific 19-hydroxy derivatives, 18,19-dehydro derivatives of PGE₁ and PGE₂. The objective of this study is to synthesize the available literature of in vivo animal studies and human clinical trials on the association between the AA pathway and male fertility. PGE is significantly decreased in the semen of infertile men, suggesting the potential for exploitation of PGE agonists to improve male fertility. Indeed, ibuprofen can affect male fertility by promoting alterations in sperm function and standard semen parameters. The results showed that targeting the AA pathways could be an attractive strategy for the treatment of male fertility.

Prostaglandins in stallion semen

The purpose of the experiment was to obtain preparatory information about the presence of prostaglandins in semen collected from various types of horses after different periods of sexual rest. Semen was collected with an artificial vagina. Prostaglandin-like activity was estimated by the bioassay procedure described by Vane (1). Results are expressed in ng/ml PGE(2) of seminal plasma. The total concentration of prostaglandins in the full ejaculate averaged 43.73 +/- 4.93 ng/ml of plasma while the total amount of prostaglandins in the ejaculate was 1076 ng. Taking into consideration the period of sexual rest in the stallion, statistically significant differences were found in the prostaglandin level in the semen of all the stallions.

Determination of prostaglandins in human seminal fluid by solid-phase extraction, pyridinium dichromate derivatization and high-performance liquid chromatography

Prostaglandins of the E type (PGEs) in human seminal fluid have been determined by reversed-phase high-performance chromatography on a C18 column and ultraviolet detection at 230 nm after solid-phase extraction (C18) and oxidation to the corresponding 15-oxoprostaglandin derivatives by pyridinium dichromate in acetonitrile. Under optimized conditions, PGEs from 10-ml seminal samples were extracted into 4 ml of methyl formate with high recoveries (estimated at greater than 95%) and subsequently separated under mild chromatographic conditions (0.5 mM formic acid-acetonitrile, apparent pH 3.8). Comparable analytical sensitivities were obtained with detection at 230 nm with a conventional deuterium lamp spectrophotometer and a photometer equipped with a cadmium emission source, while with a diode-array spectrophotometer, signal-to-noise ratios were reduced with factors between 4.4 and 3.1, depending on the spectral bandwidth of the instrument. Theoretical aspects of signal-to-noise optimization of ultraviolet detectors are discussed. The stability of dilute standard solutions of PGE2 and PGD2 was measured, showing solutions in dichloromethane at 20 degrees C to be as stable as acetonitrile solutions at 5 degrees C over a period of thirty days. Absolute ethanol and acetonitrile were equally suited as solvents.

Acrosome reaction and concentration of prostaglandin E2 in semen of rams treated with flunixin meglumine (Banamine)

The objectives of this study were to determine 1) the effect of Banamine on the seminal concentration of PGE2 and 2) the ability of sperm cells from treated rams to undergo acrosome reaction in vitro as an indirect measure of their fertilizing capacity. Seven rams, approximately 55 kg bodyweight and 2 to 5 yr of age, were divided into two groups: Group 1, treated (n = 4) and Group 2, controls (n = 3). Treatment consisted of administration of 75 mg i.m. Banamine twice daily, 6 to 8 h apart, for 45 d. On Day 0 (first day of treatment) and on Days 2, 9, 11, 16, 23, 25, 28, 30, 36, 39, 43 and 46 semen samples were collected from both groups using an electroejaculator. Blood samples were obtained for determination of serum levels of Banamine using high-performance liquid chromatography. Semen samples were examined for motility and morphology. Highly motile (>/=85%), normal-appearing semen samples were pooled on each day of collection and 25 ul of the pooled sample (1x10(6)/ml) of each group were induced to undergo acrosome reaction in vitro using ionophore A23187. Acrosome reaction was demonstrated using a staining technique designed for demonstrating the process in bull sperm cells. The percentage of acrosome-reacted and non-acrosome-reacted sperm was determined by random microscopic examination of 100 sperm cells using a double-blind approach. The supernatants of the remainder of the semen samples were assayed for levels of PGE2 using RIA. Values for acrosome-reacted sperm cells and PGE2 levels on the first day of treatment from both groups were compared with corresponding values from each day of sampling using Wilcoxon Rank Sums test (P<0.05). In Group 1, the mean serum level of Banamine was 3.02+/-0.58ug/ml. There was a significant increase in the ability of sperm cells from rams in Group 1 to undergo acrosome reaction as treatment progressed compared with the sperm cells from rams in Group 2. However, there was a significant decrease in concentration of PGE2 in semen from rams in Group 1 compared with those from Group 2. The results of this study suggest an inverse relationship between the capacity of sperm cells to undergo acrosome reaction and concentration of PGE2 in semen of rams treated with a nonsteroidal anti-inflammatory drug.

Concentration of prostaglandins in seminal fluid of fertile men

Semen samples from 31 men, all of whom had fathered a child within the preceding year, were analysed for sperm characteristics and for the content of prostaglandins (PGs). Mean concentrations (mg/l) for the four main groups of PGs were 67.1 for PGE, 3.2 for PGF, 245.7 for 19-hydroxy-PGE and 13.3 for 19-hydroxy-PGF. The individual values were distributed over a relatively wide range but the extremely wide ranges reported by previous authors were not confirmed. Information is also presented concerning the relative proportions of the four isomers of PGF, as well as those of 19-hydroxy-PGF. Only sperm density was related to PG concentration in fertile men. Polyzoospermia was associated with a low PGE concentration.

Prostaglandins in semen and their relationship to male fertility: a study of 145 men

Prostaglandin (PG) F2 alpha and PGE were measured in 163 semen samples from 145 men attending our male infertility clinic. In addition, each semen sample was analyzed for 13 different fertility parameters. Blood plasma levels of testosterone, follicle-stimulating hormone, and luteinizing hormone were also determined in many of the patients. The data obtained were then analyzed using multiple regression analyses on each PG for all of the parameters studied. The results indicate seminal PGF2 alpha and PGE concentrations were 2.78 +/- 0.24 micrograms/ml and 46.0 +/- 4.5 micrograms/ml, respectively. The seminal parameters that were significant predictors of seminal PGF2 alpha included: Ca++ concentration (P less than 0.001), Zn++ concentration (P less than 0.01), and percentage of tapered sperm (P less than 0.05). The seminal parameters that were significant predictors of seminal PGE included: Ca++ concentration (P less than 0.01) and sperm motility (P less than 0.05). Plasma testosterone was also a significant predictor of seminal PGE (P less than 0.05). These results suggest that seminal PGs are important to the human male fertility potential in that their levels are significantly interdependent with specific parameters of male fertility.

The influence of prostaglandins on sperm motility

Prostaglandin E2 and F2 alpha were measured in ejaculates from 10 fertile and 55 infertile men. Prostaglandin F2 alpha was negatively correlated with motility (r = 0.77; p less than 0.01) in normal men. In patients with disturbed fertility, prostaglandin F2 alpha was always higher than in the controls, while prostaglandin E2 was elevated only in patients with persisting varicocele and in those with very low sperm counts and severely impaired motility. There was neither de novo synthesis of prostaglandins in spermatozoa nor were binding sites for prostaglandin E2 and F2 alpha detectable. Inactivation of seminal prostaglandins by incubation with prostaglandin 15-hydroxydehydrogenase resulted in a dramatic fall in motility. The results suggest that prostaglandin F2 alpha act on motility, but the action is not mediated by receptors.

Prostaglandin E1 and E2 in bovine semen: quantification by gas chromatography

Prostaglandins PGE1 and PGE2 extracted from bovine semen, purified via silicic column chromatography were quantified by gas chromatography as their methoxime methyl ester trimethylsilyl ether derivatives. The PGE2 and PGE2 concentrations of 19 bovine semen samples ranged from 395 +/- 225 and 487 +/- 407 ng/ml, respectively. A constant 1:1 ratio between PGE1 and PGE2 was observed. There was not relationship between PGE and sperm motility, but high sperm counts were generally associated with decreased PGE levels. The direct precursors of PGE1 and PGE2, i.e. 20:3n6 and 20:4n6, occurred in low concentrations compared to other related unsaturated fatty acids, i.e. 18:2n6 and 22:5n6 of the n-6 family.

The possible mode of action of prostaglandins: XVI. A study to assess the local effect of prostaglandins E1, E2 or F2 alpha in the regulation of male fertility

A single intratesticular injection of prostaglandin E1 (PGE1) or prostaglandin E2 (PGE2) at a dose of 2.5 mg/kg was found to interfere with the fertilizing ability of epididymal spermatozoa of the test animals both in the injected and contralateral control sides. Prostaglandin F2 alpha, conversely, was found to be ineffective in terms of fertility of the test animals in the same experimental model. The beneficial effect of testosterone therapy concurrently with either of the PGE1 or PGE2 in maintaining the fertility of the animals has been recorded and discussed in terms of the mode of action of prostaglandins.

Prostaglandins E and F, and 19-hydroxylated E and F (series I and II) in semen of fertile men. Gas and liquid chromatographic separation with selected ion detection

Low concentrations of prostaglandins (PG) could be related to male clinical infertility althought relevant experimental data are scarce. The aim of this work is to establish reliable seminal PG levels in fertile men by rigorous sample control, to prevent degradation, and by rapid and simple extraction and assay procedures. Single semen samples from healthy fertile men were immediately centrifuged (within 30 min of ejaculation) adding PGF2 alpha D4 to the seminal plasma as internal standard. The samples were next ultrafiltered and the PGs in the ultrafiltrate were derivatized with a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide and piperidine (1:1) at 60 degrees for 30 min. Optimum gas-liquid chromatographic separation of all of the peaks of interest was achieved on 4 m x 1/4 in. I.D. Dexsil 300 packed columns at 280 degrees. The detection and quantitation of all the peaks of interest depends on the selected ion monitoring of specific masses. The values obtained (in micrograms/ml, range in parentheses) were: PGEs, 63.5 +/- 49.3 (9--164); PGFs, 2.6 +/- 1.92 (0.95--6.63); 19-OH PGEs, 592.6 +/- 312.5 (142.1--1047); and 19-OH PGFs, 12.66 +/- 5.21 (4--19). Individual values for members of both series I and II are also presented. The sample collection and extraction procedures were further checked by high-performance liquid chromatography on a muPorasil column, with individual isolation and collection of all of the PGs, including the 19-OH PGs not previously separted by liquid chromatography.

Similar effects of prolactin and dbcAMP upon human spermatozoa metabolism

Studies were carried out of the effects of prolactin (0.5-1.0 mU) and 3'5' dibutyryl cyclic AMP -(dbcAMP) (100-500 ng) on oxygen uptake and (U-14C) glucose and (1-14C) acetate utilization by human spermatozoa. Both molecules induce a significant increase (P < 0.01) in oxygen uptake when acetate, glucose, pyruvate and lactate were used as substrates, although differences were noted in the induction effect depending on the substrate used (Tukey's multiple comparisons after ANOVA) (P < 0.01). The production of 14CO2 from glucose and labelled acetate was also statistically increased (P < 0.01) by prolactin (from 15.15 to 25.32 nmoles CO2/hour/10(8) sperm cells) as well as by dbcAMP (15.15 to 34.95 nmoles CO2/hour/10(8) sperm cells). From these results we conclude that the activator effects of prolactin and dbcAMP on human spermatozoa with respect to the studied parameters are similar and that prolactin may be an activator of spermatic adenylyl cyclase.

Physiologic and pharmacologic studies on the motility of isolated guinea pig cauda epididymidis

The effects of norepinephrine, phentalamine, oxytocin, vasopressin, several prostaglandins, and indomethacin on the spontaneous motility of isolated guinea pig cauda epididymidis were explored. Phentolamine and indomethacin reduced the isometric peak tension of spontaneous epididymal contractions. Phentolamine also depressed the frequency. Both findings suggest that catecholamines and endogenous prostaglandins are in some way regulators of the spontaneous motility of the cauda epididymidis. Norepinephrine resulted in the development of a distinct, sustained, tonic contraction without phasic activity, whereas prostaglandins E1, E2, and F2 alpha elicited a tonic increase accompanied by frequent, superimposed, phasic contractions. Both oxytocin and vasopressin comparably enhanced epididymal motility, producing contractile responses similar to those observed with prostaglandins. Since the epididymal contractions can influence the time spent by spermatozoa in passing through the ductus epididymidis, the above-mentioned compounds could play an important role in spermatozoal transport via modulation of epididymal contractile activity. In addition, such naturally occurring substances might regulate the release of sperm from the last portion of the epididymis into the ductus deferens.

The effect of locally administered PGE2 on the contractility of the nonpregnant human uterus in vivo

The effect of locally administered prostaglandin E2 on the sensitivity and reactivity of the nonpregnant human uterus during the menstrual cycle was studied in seven women. An increase in uterine contractility in response to as little as 0.25 mug PGE2 could be observed during both the mid-proliferative and mid-secretory phases of the menstrual cycle, but around ovulation a marked decrease in sensitivity to PGE2 was noted. An inhibition of uterine motility was observed during menstruation in response to 30--40 mug PGE2. Endogenous E prostaglandin normally occurs in the secretory endometrium in levels comparable to the amount of exogenous PGE2 which elicited increased or decreased uterine activity in this study. These findings suggest that PGE2 may play an important role in the cyclical regulation of uterine motility during the menstrual cycle.