Kinetics of myo-inositol loading in women of reproductive age.
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) micro mol/L and 1.09 (0.11) micro mol/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.
Groenen
Pascal M W
PM
Departments of Epidemiology and Biostatistics & Obstetrics and Gynaecology, University Medical Center Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Merkus
Hans M W M
HM
Sweep
Fred C G J
FC
Wevers
Ron A
RA
Janssen
Fokje S M
FS
Steegers-Theunissen
Régine P M
RP
D000328:Adult; D002849:Chromatography, Gas; D005260:Female; D006801:Humans; D007294:Inositol / Q000097:blood* / Q000494:pharmacology / Q000652:urine; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008954:Models, Biological; D011863:Radioimmunoassay / Q000379:methods; D013997:Time Factors
D007328:Insulin; D007294:Inositol