Effect of pinitol treatment on insulin action in subjects with insulin resistance.
OBJECTIVE
Endogenous low-molecular-weight glycans containing pinitol (3-O-methyl-D-chiro-inositol) and D-chiro-inositol are thought to mediate certain actions of insulin. We tested the hypothesis that oral administration of soybean-derived pinitol would improve insulin sensitivity in obese subjects (BMI = 36.6 kg/m2) with diet-treated type 2 diabetes or glucose intolerance (HbA1c = 6.8%).


METHODS
There were 22 subjects randomized to receive either pinitol 20 mg x kg(-1) x day(-1) (n = 12) or placebo (n = 10) in a 28-day double-blinded trial.


RESULTS
No toxicity due to the pinitol was observed during the study The sensitivity of glucose and lipid metabolism to insulin were assessed by measurement of whole-body glucose, palmitate, and glycerol kinetics during basal conditions and a hyperinsulinemic-euglycemic clamp. Metabolic measurements were made at baseline and again at the end of the study Final plasma levels of pinitol were 48-fold (1.06 +/- 0.15 vs. 0.02 +/- 0.01 micromol/l, P < 0.0001) and D-chiro-inositol levels 14-fold (0.56 +/- 0.08 vs. 0.04 +/- 0.02 micromol/l, P < 0.0001) greater in the pinitol group compared with placebo.


CONCLUSIONS
Four weeks of pinitol treatment did not alter baseline glucose production, insulin-mediated glucose disposal, or rates of appearance of free fatty acids and glycerol in plasma. We conclude that plasma levels of both pinitol and D-chiro-inositol are very responsive to pinitol ingestion, but insulin sensitivity does not increase after pinitol treatment in individuals with obesity and mild type 2 diabetes.
Davis
A
A
Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri 63110, USA. davis_a@kids.wustl.edu
Christiansen
M
M
Horowitz
J F
JF
Klein
S
S
Hellerstein
M K
MK
Ostlund
R E
RE
D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D015309:Glucose Clamp Technique; D018149:Glucose Intolerance / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D006946:Hyperinsulinism; D007262:Infusions, Intravenous; D007294:Inositol / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology
D001786:Blood Glucose; D007328:Insulin; C021730:pinitol; D007294:Inositol