In vivo chiro-inositol metabolism in the rat: a defect in chiro-inositol synthesis from myo-inositol and an increased incorporation of chiro-[3H]inositol into phospholipid in the Goto-Kakizaki (G.K) rat.
We report our comparative studies of myo- and chiro-[3H]inositol distribution in control nondiabetic Wistar and spontaneous nonobese insulin-resistant Type II diabetic G.K. rat tissues following 78-h labeling period. From various tissue extracts, free inositols, inositol phosphates, and inositol phospholipids were isolated and analyzed. Our findings demonstrate (1) a significant difference in the metabolism of myo- and chiro-inositol in normal Wistar and G.K. rats, (2) a severe defect in conversion of myo-[3H]inositol to chiro-[3H]inositol at the inositol phospholipid level of insulin-sensitive tissues of the G.K. rat, (3) an increased incorporation of myo-[3H]inositol into purified inositol phospholipids of the G.K. rat consistent with a decreased conversion to chiro-[3H]inositol, (4) the presumed presence of a pathway which incorporates chiro-[3H]inositol into inositol phospholipids, and which is overactive in the G.K. rat compared to the Wistar rat, and (5) no or minimal conversion of chiro-[3H]inositol to myo-[3H]inositol.
Department of Biochemistry, Gyeongsang National University, Chinju, Korea. ybpak@nongae.gsnu.ac.kr
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Pak
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Hong
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Kim
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Piccariello
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Farese
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Larner
D000818:Animals; D002855:Chromatography, Thin Layer; D007294:Inositol / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism; D008297:Male; D010716:Phosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D014018:Tissue Distribution; D014316:Tritium
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D010743:Phospholipids; D014316:Tritium; D007294:Inositol