Inositol-1-phosphatase of human erythrocytes is inhibited by therapeutic lithium concentrations

Galila Agam, Avinoam Livne

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Lithium is widely used in psychiatric chemotherapy and is especially effective in the treatment of manic-depressive illness (MDI), but the mechanism for its therapeutic properties and side effects remains to be elucidated. One of the possibilities relates to the inhibitory effect of Li+ on inositol-1-phosphatase (I-1-P'ase) activity. Indeed, the concentration of inositol-1-phosphate (I-1-P) after treatment with Li+ was shown to be increased in various mammalian cells. Yet, no direct study of I-1-P'ase activity in human cells has been reported. Erythrocytes are readily accessible for routine studies and could facilitate the investigation of I-1-P'ase as affected by Li+ in relation to MDI. It is now shown that I-1-P'ase can be measured in lysate of human erythrocytes, using a small blood sample. The enzymatic activity is localized in the soluble fraction. The Km for I-1-P is 0.14 mM. Intriguingly, the Ki for Li+ is 0.86 mM, within the range of therapeutic concentrations in MDI patients.

Original languageEnglish
Pages (from-to)217-224
Number of pages8
JournalPsychiatry Research
Issue number2
StatePublished - 1 Jan 1989


  • Inositol-1-phosphatase
  • affective disorder
  • erythrocyte
  • lithium

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry


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