A method for determination of prostaglandins in human seminal fluid

Metabolism of prostaglandin E analogs in the guinea pig liver mitochondrial fraction

Tritium-labeled 16,16-dimethyl-PGE2 and 9-methylene-PGE2 were incubated with the guinea pig liver mitochondrial fraction. The tetranor and dinor metabolites were obtained, a large portion of the latter contained a saturated carboxyl side chain. Also the beta-hydroxydinor metabolites, analogous to the beta oxidation of fatty acids, were identified. Such metabolites have not been reported earlier in connection with beta oxidation of prostaglandins or prostaglandin analogs. Furthermore, omega-hydroxylated analogs were incubated with the guinea pig liver mitochondrial fraction and were found to pass through beta oxidation to a certain extent.

Quantification of prostaglandins in human seminal fluid

A method is described for measurement of the prostaglandins present in human seminal plasma. The PGEs and the 19-hydroxy-PGEs are converted to the respective PGB-compounds. They are determined with UV-absorbance after purification with two chromatography steps. The PGFs and the 19-hydroxy-PGFs are determined by gas chromatography, which also allows measurement of the 8 beta-isomers. Recovery of added PG was in the average 99.2% (range 89.9-107.7). Mean variation between duplicate analyses was 5.6% (range 0.9-9.1). The method has been simplified to allow at least limited clinical use.

Prostaglandins and cyclic-AMP in human semen

Normospermic, oligospermic and azoospermic semen samples were analysed for prostaglandins of the E groups and for cyclic AMP. The whole procedure was rapidly performed in a nitrogen atmosphere. Higher levels of total PGEs (PGEs+19-hydroxy PGEs) were found in normospermic (135.6 micrograms/ml) than in either oligospermic or azoospermic semen. The average level of cyclic AMP in normospermic semen (32.0 nmole/ml) did not differ significantly from the test groups, but very low levels were found only in oligo and azoospermic semen. The correlation coefficient between cyclic AMP and total-PGE concentrations was +0.36. The correlation coefficient between cyclic AMP level and percentage of motile sperm cells was +0.56 (p less than 0.0005). Patients who were treated for two months with a daily dose of 50mg clomiphene citrate exhibited significant elevation of cyclic AMP in their seminal fluid. This finding suggests that cyclic AMP is important for sperm motility and that the clomiphene effect on human semen may be mediated by cyclic AMP.

Effect of some saturated and unsaturated fatty acids on in vitro platelet utilization of arachidonic acid

The effect of some saturated and unsaturated fatty acids pre-incubated with human washed platelets was examined on the platelet utilization of (1-14C) arachidonic acid. The platelets were incubated with the radioactive arachidonic acid for periods of either 10 min or 30 sec. The following results were obtained. Conversion of arachidonic acid to thromboxane B2 was increased during 10 min in the presence of oleic, alpha-linolenic and lauric acids. Increased conversion of 14C-arachidonic acid to hydroxy fatty acids (HHT and HETE) was observed in the presence of stearic acid (10 min incubation) and lauric acid (30 sec incubation). Their synthesis, however, was decreased in presence of gamma-linolenic acid (10 min incubation). Endoperoxide generation from arachidonate was reduced by alpha-linolenic acid but increased by stearic acid. The conversion to PGE2 was not altered by these acids during 10 min incubation with arachidonic acid. However, in presence of gamma-linolenic, lauric and stearic acids conversion of arachidonic acid into PGE2 during 30 sec incubation was increased. Under these conditions, production of PGF2 alpha and PGD2 remained unchanged.

Metabolism of arachidonic acid by platelets: utilization of arachidonic acid by human platelets in presence of linoleic and dihomo-gamma-linolenic acids

In vitro human platelet prostaglandin synthesis has been studied from added radioactive arachidonic acid (i) as function of substrate concentration, (ii) as function of platelet concentration and (iii) as function of pH. Platelets, as in platelet rich plasma when labelled with arachidonic acid, washed and treated with thrombin, released radioactivity mainly from phosphatidylcholine and phosphatidylinositol. The released radioactivity was mostly accounted for by the formation of the previously identified oxygenation products of arachidonic acid. Platelet utilization or arachidonic acid was also studied in presence of linoleic and dihomo-gamma-linolenic acids, the two essential fatty acids known for antithrombotic effect. At its high concentrations linoleic acid decreased platelet cyclo-oxygenase activity as seen by a decreased formation of endoperoxides from arachidonic acid. Dihomo-gamma-linolenic acid was found to be a mutually competitive substrate with arachidonic acid for the platelet prostaglandin synthetase thus causing reduced utilization of arachidonic acid as shown by measuring the various oxygenation products of arachidonic acid. These two acids were utilized differently by platelet prostaglandin synthetase.

Utility of d4-PGE2 as an internal standard to quantify endogenous levels of PGE1, PGE2, 19OH PGE1 and 19OH PGE2 in human seminal fluid by GC-MS-SIM

Four prostaglandins-PGE1, PGE2, 19OH PGE1 and 19OH PGE2-were quantified in human seminal fluid by GC-MS-SIM using only the internal standard, d4-PGE2. Methods and calculations were developed to minimize errors inherent in using only one internal standard for quantifying four closely related prostaglandins. Preliminary data concerning the statistical significance of the difference found between PGE and 19OH PGE levels in fertile, azospermic and oligospermic men are reported.

Direct quantitative thin-layer chromatographic determination of prostaglandins A2, B2, E2 and F2 alpha

A direct method for the determination of prostaglandins (PG) A2, B2, E2 and F2 alpha by thin-layer chromatography (TLC) is described. The TLC development is carried out on silica gel 60 F254 plates so that PGA2, PGB2 and PGE2 can be directly determined together by chromatogram spectrodensitometry using the reflection method. PGE2 must be converted into pgb2 so that it can be measured at lambda max. 224 nm and after conversion into PGB2 by spraying with potassium hydroxide solution. PGF2 alpha is measured after spraying with methanolic sulphuric acid and subsequent heating at lambda max. 530 nm. The method of determination described here is characterized by a short analysis time and good accuracy, and it is therefore suitable for quality control and stability investigations with these prostaglandins. The coefficient of variation is plus or minus 3.5 percent.

The synthesis of prostaglandins in platelets from patients with multiple sclerosis

As a continuation of our previous studies on the synthesis of prostaglandins (PGs) in human thrombocytes, the present study concerns the biosynthesis of PGs in thrombocytes from patients with multiple sclerosis, as this condition has been suggested to be linked to thrombotic and/or thrombocyte abnormalities. It was found that in these patients a statistically decreased synthesis of PGE1, PGE2 and PGF took place compared to the corresponding values in normal subjects. The ratio between PGE1 and PGE2 was, however, unchanged.

Uptake and inactivation of a-type prostanglandins by human red cells

Incubation of A type prostaglandins with whole blood or washed red cells at 37 degrees C converted them to more polar products with negligible vasodepressor and smooth muscle-contracting activities. This conversion did not occur in platelet-rich plasma. Uptake of the prostaglandins by red cells was demonstrated at both 4 degrees C and 37 degrees C. The data suggest 1) that if PGA is released from tissues into the blood stream or is administered for therapeutic purposes, its biological activity would be diminished by human red cells, and 2) that development of an assay for PGA in blood should take into account its uptake and metabolism by human red cells.

Prostaglandins: a report on early clinical studies

The prostaglandins are a unique group of pharmacologically active lipids which are widely distributed in mammalian tissues and body fluids. The chemistry of this family of compounds has been established in elegant detail. Research quantities of these highly active natural compounds were obtained by enzymatic bioconversion of essential fatty acids and now studies devoted to the elucidation of their physiological roles and their clinical potential are progressing rapidly. Fields of greatest current interest in clinical medicine include renal-cardiovascular research, induction of labour and therapeutic abortion, control of the reproductive cycle (including fertility control), bronchodilation, enhancement of nasal patency and antisecretory activity. Results available to date are too preliminary for many conclusions to be drawn, but are sufficiently encouraging to assure continued and expanding efforts in several fields.