In vivo conversion of [3H]myoinositol to [3H]chiroinositol in rat tissues.
We report here the in vivo conversion of [3H]myoinositol to [3H]chiroinositol. After labeling intraperitoneally with [3H]myoinositol for 3 days to reach radioisotope equilibrium in urine, [3H]chiroinositol was isolated from tissues and purified after 6 N HCl hydrolysis by two sequential paper chromatographies and high performance liquid chromatography (HPLC). Percent conversion of [3H]myoinositol to [3H]chiroinositol was highest in urine (36%), liver (8.8%), muscle (8.8%), and blood (7.6%) with intestine, brain, kidney, spleen, and heart decreasing in percentage from 2.8 to 0.7%. Labeling of other inositol isomers including scyllo-, neo-, and epi-, and mucoinositol was minimal, approximately 0.06% of [3H]myoinositol. Glucose was unlabeled, but glucuronate, the product of myoinositol oxidation, was labeled up to 1.5% of the [3H] myoinositol. Acid hydrolysates of combined inositol-containing phospholipids contain significant labeled chiroinositol. [3H]Phosphatidylinositols and [3H]glycosylphosphatidylinositols were extracted from liver, muscle, and blood, isolated by thin layer chromatography, and inositols purified by HPLC after acid hydrolysis. Percent conversion of [3H]myoinositol to [3H] chiroinositol was highest in blood (60.4%) followed by muscle (7.7%) and liver (2.2%).
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Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville 22908.
Huang
L C
LC
Lilley
K J
KJ
Larner
J
J
D000818:Animals; D001711:Biotransformation; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D002854:Chromatography, Paper; D006017:Glycolipids / Q000302:isolation & purification / Q000378:metabolism; D017261:Glycosylphosphatidylinositols; D007294:Inositol / Q000302:isolation & purification / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008297:Male; D009928:Organ Specificity; D010716:Phosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013237:Stereoisomerism
D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D010716:Phosphatidylinositols; D007294:Inositol