代谢
麦芽糖醇（4-α-D-葡萄糖基山梨醇）的代谢在禁食常规（C）大鼠、C小鼠和无菌（GF）小鼠中进行评估，使用[U-14C]麦芽糖醇。在给予标记麦芽糖醇后48小时内收集的(14)CO2的放射性呼吸模式表现为C大鼠和小鼠在持续4小时内的(14)CO2产生速率恒定。GF小鼠的模式在第二小时出现峰值，随后立即缓慢下降。GF小鼠的(14)CO2回收百分比（59%）显著低于C动物（72-74%）。48小时后，C大鼠和小鼠的尿液、粪便和肠内容物总计占给药放射活性的19%，GF小鼠为39%。还评估了GF小鼠对麦芽糖醇的消化性和山梨醇的吸收。GF小鼠在给予等摩尔量的麦芽糖醇（140 mg/kg体重）或山梨醇（70 mg/kg体重）3小时后，盲肠和小肠分别含有摄入剂量的39%和51%，大部分以山梨醇的形式存在于盲肠中。GF小鼠的小肠的α-葡萄糖苷酶（麦芽糖酶）活性显著高于C小鼠（1.5-1.7倍）。这些结果表明，小鼠和大鼠小肠中的酶活性足以广泛水解麦芽糖醇。因此，山梨醇的缓慢吸收似乎是限制麦芽糖醇在小肠中整体吸收的重要因素。
The metabolism of maltitol (4-alpha-D-glucosylsorbitol) was assessed in fasting conventional (C) rats, C mice and germ-free (GF) mice, using [U-14C]maltitol. The radiorespirometric patterns of (14)CO2 collected for 48 hr after the administration of labelled maltitol were characterized by a constant rate of (14)CO2 production lasting 4 hr for both C rats and mice. The pattern for the GF mice showed a peak at the second hour followed immediately by a slow decrease. The percentage recovery of (14)CO2 was significantly lower for the GF mice (59%) compared with C animals (72-74%). Urine, feces and intestinal contents after 48 hr totalled 19% of the administered radioactivity in the C rats and mice and 39% in the GF mice. The digestibility of maltitol and the absorption of sorbitol in GF mice was also assessed. The cecum and small intestine of GF mice, 3 hr after administration of equimolar quantities of maltitol (140 mg/kg body-weight) or sorbitol (70 mg/kg body-weight), contained 39 and 51% of the ingested dose respectively, present mostly in the cecum as sorbitol. The alpha-glucosidase (maltase) activity of the small intestine was appreciably higher (1.5-1.7 times) in the GF mice than in the C mice. These results suggest that the enzymic activities in the small intestine of mice and rats are sufficient to hydrolyse maltitol extensively. Consequently, the slow absorption of sorbitol seems to be an important factor limiting the overall assimilation of maltitol in the small intestine.
来源:Hazardous Substances Data Bank (HSDB)
