Stimulation of androgen production by D-aspartate through the enhancement of StAR, P450scc and 3β-HSD mRNA levels in vivo rat testis and in culture of immature rat Leydig cells.
Previous studies have shown a role of d-aspartic acid (d-Asp) in testicular steroidogenesis. Here, we evaluated the effects of d-Asp on androgen production and on expression levels of mRNAs encoding specific steroidogenic key molecules. d-Asp was endogenously present in adult rat testis and its content paralleled to serum luteinizing hormone (LH) and, local and circulating androstenedione and testosterone levels. In vivod-Asp administration induced serum LH release, causing an indirect increase of androstenedione and testosterone levels by enhancing steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase/D5-D4 isomerases (3β-HSD) mRNA levels. The direct endocrine role of d-Asp was evaluated using cultured immature Leydig cells (ILCs) obtained from 35days old rats. Cytoplasm and nucleus of ILCs localized d-Asp, while StAR marked the cytoplasm only. After 12h from d-Asp in vitro administration, ILCs resulted intensely d-Asp stained, and StaR protein level, evaluated by Western blotting, significantly increased. After 24h, significant androstenedione and testosterone syntheses were induced. At molecular level, d-Asp administration significantly increased StAR, P450scc and 3β-HSD mRNAs at 2, 4 and 12h, respectively. The temporal shift on relative mRNA expression levels indicated that d-Asp exerted its physiological role through sequential gene cascade activation of those molecules implicated in the synthesis of androgens. Conclusively, our findings demonstrated that d-Asp is a local messenger in testis and give a contribution in understanding the complexity of local endocrine regulation as well as the molecular events leading the acquisition to a steroidogenic competence by ILCs.
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy. Electronic address: francaraucci@hotmail.com.
Franca
F
Raucci
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy.
Antimo
A
D'Aniello
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy.
Maria Maddalena
MM
Di Fiore
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D000728:Androgens / Q000096:biosynthesis*; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D026603:D-Aspartic Acid / Q000378:metabolism*; D008297:Male; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D000098682:Steroidogenic Acute Regulatory Protein
D000728:Androgens; D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D026603:D-Aspartic Acid; D015096:3-Hydroxysteroid Dehydrogenases; D002786:Cholesterol Side-Chain Cleavage Enzyme
Androstenedione; Steroidogenesis; Testis; Testosterone; d-Aspartic acid