Metabolism of Sorbitol in the intact organism.
1) Uniformly labeled sorbitol and DD-fructose, respectively, are compared int he rat after intragastral administration in regard to their incorporation patterns into respiratory CO2, fatty acids and glycerol of adipose tissue triacyglycerols, liver cholesterol and glycogen. The results demonstrate clearly that fructose cannot be considered as the sole or main intermediate of the metabolic degradation of orally administered sorbitol in the intact organism. 2) When sulfanilamide undergoes acetylation in the rat after intragastral application of U-14C-labeled precursors, acetylsulfanilamide isolated from the urine possesses a much higher specific radioactivity after sorbitol than after fructose administration. 3) Human volunteers of both sexes exhale considerable quantities of hydrogen (H2) through their lungs, after oral sorbital administration but only small amounts after fructose administration. 4) The results prove that sorbital had been absorbed only partially in the small intestine, and undergoes fermentation in lower parts of the digestive tract (caecum in rats, colon in men) which leads, amongst other products. to acetate. Products of microbial metabolization are absorbed and utilized by the host organism. Different isotope incorporation patterns, varying specific radioactivities in acetylsulfanilamide, and H2 formationi men are thus explained. Therefore the degradation of orally administered sorbitol does not proceed in the intact organism, to a remarkable extent as is the case with fructose or other monosaccharides; pecularities of the effects of dietary sorbitol become understandable.