Spatiotemporal relationships among D-serine, serine racemase, and D-amino acid oxidase during mouse postnatal development.
OBJECTIVE
To elucidate the spatiotemporal relationships among D-serine, serine racemase, and D-amino acid oxidase (EC 1.4.3.3; DAO) in mouse cortex, striatum, cerebellum, heart, lung, liver, spleen, kidney, and skeletal muscle during mouse postnatal development.


METHODS
The transcription levels of serine racemase and DAO were assayed by reverse transcription-polymerase chain reaction (RT-PCR). The protein levels of serine racemase were examined by Western blot. DAO activities were assayed by colorimetric method. D-serine was measured by HPLC.


RESULTS
In cortex, striatum, and cerebellum, free D-serine increased drastically after birth and coincided well with the increase of serine racemase expression. However, among the 9 tissues examined, DAO activities were detected only in cerebellum and kidney. During the 3rd week, DAO activity in cerebellum and kidney increased dramatically, which concurred with the drastic decline of D-serine content in these tissues. On the other hand, while D-serine and serine racemase fall to trace level in cerebellum and kidney at the 3rd weekend, DAO activities in these tissues increased continuously.


CONCLUSIONS
The free D-serine is mainly synthesized by serine racemase. However, novel mechanisms might be involved in D-serine deposition in mouse tissues with high level of D-serine and no detectable DAO activity such as cortex and striatum. DAO in cerebellum and kidney might have other physiological functions in addition to degrading D-amino acid.
Wang
Li-Zhen
LZ
Department of Pharmacology, Institute of Materia Medica, Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Zhu
Xing-Zu
XZ
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism*; D002531:Cerebellum / Q000254:growth & development / Q000378:metabolism; D002540:Cerebral Cortex / Q000254:growth & development / Q000378:metabolism; D003342:Corpus Striatum / Q000254:growth & development / Q000378:metabolism; D003605:D-Amino-Acid Oxidase / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics; D019998:Racemases and Epimerases / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D000099300:Serine Racemase
D003605:D-Amino-Acid Oxidase; D012333:RNA, Messenger; D019998:Racemases and Epimerases; D012694:Serine; D000099300:Serine Racemase