Mammalian lipocalin-type prostaglandin D2 synthase in the fluids of the male genital tract: putative biochemical and physiological functions.
Abstract: Prostaglandin D2 synthase (PGDS) is a major epididymal secretory protein in several species. We quantified PGDS in ram and bull semen using a specific antiserum. Strong variations in PGDS concentration existed between animals. In the bull, the highest concentrations were found preferentially in animals with normal or high fertility, as was previously suggested. However, low concentrations were found in males with all ranges of fertility, suggesting that the function of PGDS either is not necessary for male fertility or can be assumed by other proteins when its concentration is low. In the ram and stallion, cDNA and deduced protein sequences of PGDS were obtained by reverse transcription-polymerase chain reaction and showed that PGDS possessed the sequences involved in the three-dimensional folding characteristic of the lipocalin family and a cysteine at position 65 that is involved in the enzymatic activity. The enzymatic activity of PGDS was estimated in the ram by in vitro incubation of epididymal-isolated tubules with radioactive arachidonic acid. Prostaglandin (PG) D2 represented approximately 10% of the PGs produced in the lumen, irrespective of the presence or absence of luminal PGDS, suggesting that this protein is not involved in PGD2 biosynthesis. These results were corroborated by the absence of conversion of PGH2 to PGD2 when epididymal fluids were incubated with PGH2. In the rat, inhibition of PG biosynthesis in vivo by nonsteroidal anti-inflammatory drugs for 60 days did not change spermatozoa mobility or male fertility. It is likely that PGDS, which has a structure similar to that of lipocalin, functions as a lipophilic carrier protein, because we have shown that epididymal PGDS binds retinoic acid and testosterone in vitro.
Publication Date: 2002-01-24 PubMed ID: 11804963DOI: 10.1095/biolreprod66.2.458Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study investigates the role of Prostaglandin D2 Synthase (PGDS) – a key epididymal secretory protein found in various species – in male fertility. It explores the concentration of PGDS in ram and bull semen and its correlation with their fertility rate while also analysing its structure and potential functions.
Research Methodology and Data
- The researchers quantified the Prostaglandin D2 Synthase (PGDS) present in the semen of rams and bulls. To achieve this, they used a distinctive antiserum. They found significant variations in PGDS concentrations among the animals.
- The highest PGDS concentrations were predominantly found in bulls with normal or high fertility rates. Lower concentrations were evident in lower fertility ranges, suggesting PGDS function is not crucial for male fertility or can be compensated by other proteins if its level is low.
- They also acquired the cDNA and deduced protein sequences of PGDS in ram and stallion. This was done by reverse transcription-polymerase chain reaction. The PGDS confirmed to possess the sequences involved in the three-dimensional folding feature of the lipocalin protein family. Moreover, a cysteine at position 65 was found to be involved in its enzymatic activity.
Insights on the Enzymatic Activity of PGDS
- They estimated the enzymatic activity of PGDS in rams by in vitro incubation of epididymal-isolated tubules with radioactive arachidonic acid. Prostaglandin (PG) D2 was found to represent around 10% of the PGs produced in the lumen, irrespective of the presence or absence of luminal PGDS, indicating this protein isn’t involved in PGD2 biosynthesis.
- This observation was reinforced when there was no conversion of PGH2 to PGD2 during an experiment where epididymal fluids were combined with PGH2.
- To further investigate, the researchers inhibited PG biosynthesis in vivo in rats using nonsteroidal anti-inflammatory drugs over 60 days. The results showed no changes in sperm mobility or male fertility, further challenging the association of PGDS with fertility.
Conclusion and Potential Role of PGDS
- Given its similar structure with lipocalin and the experimental results, the PGDS is likely to act as a lipophilic carrier protein. This assertion is supported by evidence showing that epididymal PGDS successfully binds with retinoic acid and testosterone in vitro.
Cite This Article
APA
Fouchécourt S, Charpigny G, Reinaud P, Dumont P, Dacheux JL.
(2002).
Mammalian lipocalin-type prostaglandin D2 synthase in the fluids of the male genital tract: putative biochemical and physiological functions.
Biol Reprod, 66(2), 458-467.
https://doi.org/10.1095/biolreprod66.2.458 Publication
Researcher Affiliations
- Laboratoire de Physiologie Animale, INRA, 78352 Jouy-en Josas, France.
MeSH Terms
- Amino Acid Sequence
- Animals
- Anti-Inflammatory Agents, Non-Steroidal / pharmacology
- Cattle
- Cyclooxygenase 1
- Cyclooxygenase 2
- DNA, Complementary / biosynthesis
- DNA, Complementary / genetics
- Epididymis / metabolism
- Fertility / drug effects
- Genitalia, Male / enzymology
- Genitalia, Male / physiology
- Horses
- Immunoblotting
- Indicators and Reagents
- Intramolecular Oxidoreductases / metabolism
- Intramolecular Oxidoreductases / physiology
- Isoenzymes / metabolism
- Lipocalins
- Male
- Molecular Sequence Data
- Prostaglandin-Endoperoxide Synthases / metabolism
- RNA, Messenger / biosynthesis
- Reverse Transcriptase Polymerase Chain Reaction
- Semen / enzymology
- Sheep
- Sperm Motility / drug effects
- Spermatozoa / drug effects
Citations
This article has been cited 2 times.- Hoxha M, Barbonetti A, Zappacosta B. Arachidonic Acid Pathways and Male Fertility: A Systematic Review.. Int J Mol Sci 2023 May 3;24(9).
- Mueller JL, Ripoll DR, Aquadro CF, Wolfner MF. Comparative structural modeling and inference of conserved protein classes in Drosophila seminal fluid.. Proc Natl Acad Sci U S A 2004 Sep 14;101(37):13542-7.
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