D-chiro-inositol metabolism in diabetes mellitus.
D-chiro-inositol is a rare inositol isomer present in inositol phosphoglycans which are proposed mediators of insulin action. To study D-chiro-inositol metabolism in diabetes mellitus, a sensitive and specific assay was developed using negative-ion chemical ionization gas chromatography/mass spectrometry. Median urinary D-chiro-inositol excretion, which was 2.1 mumol/day in nondiabetics, was substantially increased to 12 mumol/day in non-insulin-dependent diabetes (P < 0.0001) and to 74 mumol/day in insulin-dependent diabetes (P < 0.0001). Urinary D-chiro-inositol was strongly correlated with fasting plasma glucose (r = 0.568, P < 0.0001), glycated hemoglobin (r = 0.529, P < 0.0001), and urinary glucose (r = 0.368, P = 0.01). The renal clearance of D-chiro-inositol was selectively elevated in both non-insulin-dependent and insulin-dependent diabetes when compared with the clearances of L-chiro-inositol or myo-inositol and exceeded the glomerular filtration rate in 71% of the diabetics but in none of the nondiabetics. In poorly controlled diabetic patients insulin treatment reduced urinary D-chiro-inositol losses by 63% and increased plasma levels by 8.8-fold. The metabolism of D-chiro-inositol is abnormal in diabetes and appears to be influenced by short- and long-term metabolic control.
Ostlund
R E
RE
Department of Medicine, Washington University, St. Louis, MO 63110.
McGill
J B
JB
Herskowitz
I
I
Kipnis
D M
DM
Santiago
J V
JV
Sherman
W R
WR
D000328:Adult; D003920:Diabetes Mellitus / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007294:Inositol / Q000097:blood / Q000378:metabolism* / Q000652:urine; D007668:Kidney / Q000378:metabolism; D008875:Middle Aged; D012016:Reference Values; D013237:Stereoisomerism
D007294:Inositol