Background: Myo-inositol plays a key role in an
important intracellular signalling pathway. A deranged myo-inositol
metabolism has been associated with neural tube defects. A
myo-inositol loading test was performed to investigate the kinetics
in healthy women of reproductive age.
Methods: Five healthy non-obese females {mean age (standard deviation:
SD) 22·8 (2·2) years} were recruited at the University Medical Center Nijmegen. Blood
samples were drawn fasting and at 20, 40, 60, 90, 180 and 270 min after ingestion of
100 mg/kg body weight of myo-inositol. Urine samples were collected
before myo-inositol loading and at 180 and 270 min post-loading.
Samples were analysed for serum myo-, epi- and
scyllo-inositol and glucose concentrations by gas chromatography.
Plasma insulin concentrations were determined by radio-immunoassay. Random intercept
models were fitted to evaluate the data.
Results: The estimated myo-inositol and
scyllo-inositol concentrations both reached maximum values at 180
min post-loading, respectively: mean (SD) 101·5 (9·2) µmol/L and
1·09 (0·11) µmol/L. The estimated plasma insulin and serum glucose
concentrations decreased slightly but significantly during the experiment:
P < 0·0001 and P < 0·05, respectively. At
180 and 270 min post-loading, urinary myo-inositol concentrations
were increased and urinary glucose concentrations were unchanged.
Conclusions: Myo-inositol enters the bloodstream
quickly after oral ingestion and a small amount of myo-inositol is
converted to scyllo-inositol. The synthesis of glucose from
myo-inositol could not be detected by serum measurements. These
data can be used in further research into the association between
myo-inositol and neural tube defects.
