Abstract
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 language | English |
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Pages (from-to) | 217-224 |
Number of pages | 8 |
Journal | Psychiatry Research |
Volume | 27 |
Issue number | 2 |
DOIs | |
State | Published - 1 Jan 1989 |
Keywords
- Inositol-1-phosphatase
- affective disorder
- erythrocyte
- lithium
ASJC Scopus subject areas
- Psychiatry and Mental health
- Biological Psychiatry