Evaluation of rat intestinal lactase in vivo with 4-galactosylxylose

Aragón, J. L.; Fernández-Mayoralas, Alfonso; Jiménez‐Barbero, Jesús; Martín‐Lomas, Manuel; Rivera‐Sagredo, Alfonso; Villanueva, Daniel

doi:10.1016/0009-8981(92)90207-7

Cited by 13 publications

(9 citation statements)

References 20 publications

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“…Upon gavage, animals were put in metabolic cages for 6 h to collect their urine for xylose content (by ion exchange chromatography (IEC)) as a measure for their intestinal lactase activity. The percentage xylose excreted in the urine was assumed to be proportional to the prevailing lactase activity as reported previously [ 10 , 11 ]. Theoretically, the maximal amount to be recovered was 25%: complete GX hydrolysis renders 50% xylose of which only about 50% is excreted by the kidney, the rest being metabolized endogenously [ 10 ].…”

Section: Methodsmentioning

confidence: 99%

Acute and Chronic Effects of Dietary Lactose in Adult Rats Are not Explained by Residual Intestinal Lactase Activity

et al. 2015

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Neonatal rats have a high intestinal lactase activity, which declines around weaning. Yet, the effects of lactose-containing products are often studied in adult animals. This report is on the residual, post-weaning lactase activity and on the short- and long-term effects of lactose exposure in adult rats. Acutely, the postprandial plasma response to increasing doses of lactose was studied, and chronically, the effects of a 30% lactose diet fed from postnatal (PN) Day 15 onwards were evaluated. Intestinal lactase activity, as assessed both in vivo and in vitro, was compared between both test methods and diet groups (lactose vs. control). A 50%–75% decreased digestive capability towards lactose was observed from weaning into adulthood. Instillation of lactose in adult rats showed disproportionally low increases in plasma glucose levels and did not elicit an insulin response. However, gavages comprising maltodextrin gave rise to significant plasma glucose and insulin responses, indicative of a bias of the adult GI tract to digest glucose polymers. Despite the residual intestinal lactase activity shown, a 30% lactose diet was poorly digested by adult rats: the lactose diet rendered the animals less heavy and virtually devoid of body fat, whereas their cecum tripled in size, suggesting an increased bacterial fermentation. The observed acute and chronic effects of lactose exposure in adult rats cannot be explained by the residual intestinal lactase activity assessed.

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Section: Methodsmentioning

confidence: 99%

Acute and Chronic Effects of Dietary Lactose in Adult Rats Are not Explained by Residual Intestinal Lactase Activity

et al. 2015

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“…To measure rat intestinal lactase, the mucosa from the medium region of the small intestine was obtained as described (14 ) and homogenized with 10 volumes of 100 mmol/L sodium maleate buffer, pH 6.0. Lactase activity was determined in the homogenate, designated the extract, as described (14 ) by measuring the released galactose with galactose dehydrogenase (22 ).…”

Section: Assay Of Intestinal Lactase Activitymentioning

confidence: 99%

“…Lactase activity was determined in the homogenate, designated the extract, as described (14 ) by measuring the released galactose with galactose dehydrogenase (22 ). One unit of enzyme activity is defined as the amount of enzyme catalyzing the conversion of 1 mol of substrate/min at 25°C.…”

Section: Assay Of Intestinal Lactase Activitymentioning

confidence: 99%

“…We developed a new, noninvasive method based on oral administration of 4-galactosylxylose, a close structural analog of lactose, which is hydrolyzed by intestinal lactase yielding 2 physiologic products, galactose and xylose (14,15 ). d-Xylose is passively absorbed from the small intestine (16,17 ) and is accumulated in the urine (14,15 ), where it could be measured by a simple colorimetric method (18 ).…”

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confidence: 99%

“…d-Xylose is passively absorbed from the small intestine (16,17 ) and is accumulated in the urine (14,15 ), where it could be measured by a simple colorimetric method (18 ). To overcome the complexity and inefficiency of the chemical synthesis of 4-galactosylxylose, we carried out an enzymatic synthesis involving only 1 reaction step (19 ), which produced a final preparation with high yield, but consisting of a mixture of 2-, 3-, and 4-galactosylxyloses ( Fig.…”

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Noninvasive Evaluation of Intestinal Lactase with 4-Galactosylxylose: Comparison with 3- and 2-Galactosylxylose and Optimization of the Method in Rats

et al. 2006

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Background: Urinary excretion of D-xylose by suckling rats after ingestion of a mixture of 4-, 3-, and 2-galactosylxyloses reflects lactase activity in vivo. We aimed to select the most convenient of these disaccharides for detecting changes of the enzyme activity in vivo and to optimize the method. Methods: 4-, 3-, and 2-Galactosylxyloses were synthesized and purified, then orally administered to suckling rats of different ages. D-Xylose was measured colorimetrically by the phloroglucinol reaction in urine and plasma. Lactase activity was determined in extracts of small intestine mucosa with lactose, galactosylxyloses, and phlorizin as substrates. Results: D-Xylose appeared in the urine in a dosedependent manner after ingestion of any of the 3 galactosylxylose disaccharides. Correlation between D-xylose elimination and intestinal lactase activity was highest with 4-galactosylxylose (r ‫؍‬ 0.97; n ‫؍‬ 24), lower with 2-galactosylxylose (r ‫؍‬ 0.89; n ‫؍‬ 24), and lowest with 3-galactosylxylose (r ‫؍‬ 0.34; n ‫؍‬ 23). The kinetic properties of intestinal lactase accounted for these differences. D-Xylose concentration in plasma after administration of 4-galactosylxylose also correlated with lactase activity (r ‫؍‬ 0.93; n ‫؍‬ 33).

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Analysis of Protein–Carbohydrate Interaction Using Engineered Ligands

Solı́s¹,

Dı́az-Mauriño²

1996

Glycosciences

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Evaluation of rat intestinal lactase in vivo with 4-galactosylxylose

Cited by 13 publications

References 20 publications

Acute and Chronic Effects of Dietary Lactose in Adult Rats Are not Explained by Residual Intestinal Lactase Activity

Acute and Chronic Effects of Dietary Lactose in Adult Rats Are not Explained by Residual Intestinal Lactase Activity

Noninvasive Evaluation of Intestinal Lactase with 4-Galactosylxylose: Comparison with 3- and 2-Galactosylxylose and Optimization of the Method in Rats

Analysis of Protein–Carbohydrate Interaction Using Engineered Ligands

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