Occurrence of D-aspartic acid in human seminal plasma and spermatozoa: possible role in reproduction.
OBJECTIVE
To determine D-aspartic acid (D-Asp) in human seminal plasma and spermatozoa in fertile and infertile donors.


METHODS
Prospective observation study.


METHODS
Department of Pathophysiology for Human Reproduction, Hospital "S. Luca," Salerno, Italy, and Department of Neurobiology and Comparative Physiology, Zoological Station "A. Dohrn," Naples, Italy.


METHODS
Ten normospermic, 10 oligoasthenoteratospermic, and 10 azoospermic (nonobstructive) men.


METHODS
D-aspartic acid was determined by a specific enzymatic high-performance liquid chromatography method on purified seminal plasma and on isolated spermatozoa and by an immunohistochemical method using light and electronic microscopic techniques.


METHODS
Concentration of D-Asp in seminal plasma and in isolated spermatozoa; subcellular localization of D-Asp in the acrosome and nucleus.


RESULTS
The concentration of D-Asp in seminal plasma and in spermatozoa was significantly reduced in oligoasthenoteratospermic donors. In the seminal fluid of normospermic donors, D-Asp occurs at a concentration of 80 +/- 12 nmol/mL semen (10.4 +/- 1.5 microg/mL), whereas 26 +/- 6 nmol/mL semen were found in oligoasthenoteratospermic donors, and 12 +/- 1.5 nmol/mL semen were found in azoospermic donors. In spermatozoa from normospermic donors, D-Asp occurred at a concentration of 130 +/-15 fmol per spermatozoa (17.0 +/- 1.96 ng per spermatozoa), vs. 60.5 +/- 5.0 fmol per spermatozoa from oligoasthenoteratospermic subjects. Other D-amino acids analyzed were not present in seminal plasma or in spermatozoa in a significant concentration compared with D-Asp.


CONCLUSIONS
D-aspartic acid occurs in human seminal plasma and spermatozoa and is implicated in male fertility.
D'Aniello
Gemma
G
Department of Obstetrics and Gynecology and Physiopathology of Human Reproduction, Hospital S. Luca, Salerno, Italy. daniello@szn.it
Ronsini
Salvatore
S
Guida
Francesco
F
Spinelli
Patrizia
P
D'Aniello
Antimo
A
D000328:Adult; D000818:Animals; D001224:Aspartic Acid / Q000032:analysis / Q000502:physiology*; D006801:Humans; D008297:Male; D049831:Octopodiformes; D011446:Prospective Studies; D012098:Reproduction / Q000502:physiology; D012661:Semen / Q000737:chemistry*; D013094:Spermatozoa / Q000737:chemistry* / Q000502:physiology
D001224:Aspartic Acid