Current knowledge of D-aspartate in glandular tissues.
Free D-aspartate (D-Asp) occurs in substantial amounts in glandular tissues. This paper reviews the existing work on D-Asp in vertebrate exocrine and endocrine glands, with emphasis on functional roles. Endogenous D-Asp was detected in salivary glands. High D-Asp levels in the parotid gland during development suggest an involvement of the amino acid in the regulation of early developmental phases and/or differentiation processes. D-Asp has a prominent role in the Harderian gland, where it elicits exocrine secretion through activation of the ERK1/2 pathway. Interestingly, the increase in NOS activity associated with D-Asp administration in the Harderian gland suggests a potential capability of D-Asp to induce vasodilatation. In mammals, an increase in local concentrations of D-Asp facilitates the secretion of anterior pituitary hormones, i.e., PRL, LH and GH, whereas it inhibits the secretion of POMC/α-MSH from the intermediate pituitary and of oxytocin from the posterior pituitary. D-Asp also acts as a negative regulator for melatonin synthesis in the pineal gland. Further, D-Asp can stereo-specifically modulate the production of sex steroids, thus taking part in the endocrine control of reproductive activity. Although D-Asp receptors remain to be characterized, gene expression of NR1 and NR2 subunits of NMDAr responds to D-Asp in the testis.
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 80100, Caserta, Italy, mariam.difiore@unina2.it.
Maria Maddalena
MM
Di Fiore
Alessandra
A
Santillo
Gabriella
G
Chieffi Baccari
D000591:Amino Acid Isomerases / Q000378:metabolism; D000818:Animals; D050804:D-Aspartate Oxidase / Q000378:metabolism; D026603:D-Aspartic Acid / Q000493:pharmacokinetics*; D004702:Endocrine Glands / Q000378:metabolism*; D005088:Exocrine Glands / Q000378:metabolism*; D006243:Harderian Gland / Q000378:metabolism; D006801:Humans; D008550:Melatonin / Q000096:biosynthesis; D010306:Parotid Gland / Q000378:metabolism; D010870:Pineal Gland / Q000378:metabolism; D052716:Pituitary Gland, Intermediate / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000378:metabolism; D010908:Pituitary Hormones, Anterior / Q000378:metabolism; D012469:Salivary Glands / Q000378:metabolism
D010908:Pituitary Hormones, Anterior; D026603:D-Aspartic Acid; D050804:D-Aspartate Oxidase; D000591:Amino Acid Isomerases; C019749:aspartate racemase; D008550:Melatonin