Alterations in serum amino acid concentrations in male and female schizophrenic patients

Background: Since several studies have investigated gender-related differences in the onset of disease, response to drug therapy, etc. in schizophrenic patients, we examined the alterations in serum amino acids concentrations in male and female patients separately. Methods: Serum amino acid concentrations in the normal (n=35; male 21 and female 14) and schizophrenic patients (n=32; male 19 and female 13) were determined by HPLC using a pre-column fluorescence derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole. Results: Serum glutamate and serine concentrations were significantly increased in the male schizophrenic patients (p=0.0161 and 0.0257, respectively), while the serum Pro concentration was significantly increased in female schizophrenic patients (p=0.0398). Serum Glu, Ser, and Pro concentrations in the patients did not significantly correlate with the age, age of onset of disease, duration of illness, and chlorpromazine equivalents. Among the amino acids, serum Om concentrations in male and female schizophrenic patients positively correlated with the duration of illness (p < 0.01, r=0.685 and 0.688, respectively). Conclusion: The present data suggest the existence of gender-related differences in the alterations in serum amino acid concentrations in schizophrenic patients; further, serum Orn concentration in both sexes might be influenced by medications. (C) 2007 Elsevier B.V. All rights reserved.