长期摄入乳糖会改变断奶大鼠单糖的胃排空，但不会改变双糖的胃排空。

da-Costa-Pinto E A, Collares E F

Departamento de Pediatria, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brasil.

Braz J Med Biol Res. 1997 Jun;30(6):723-6. doi: 10.1590/s0100-879x1997000600004.

Ninety-six weanling male Wistar rats were fed for four weeks one of two different chows: a normal rat chow containing 55.5% (w/w) starch (control group, N = 48) or a rat chow in which starch was partially replaced by lactose, in such a way that the experimental group (N = 48) received 35.5% (w/w) starch and 20% (w/w) lactose. The gastric emptying of fluid was then studied by measuring the gastric retention of four test meals containing lactose (5% or 10%, w/v) or glucose+galactose (5% or 10%, w/v). Homogenates of the small intestine were assayed for lactase activity. The gastric retention values were obtained 15 min after orogastric infusion of the liquid meals. The median values for gastric retention of the 5% lactose solutions were 37.7% for the control group and 37.0% for the experimental group (P > 0.02). For the 10% lactose solution the median values were 51.2% and 47.9% (P > 0.02) for the control and experimental groups, respectively. However, for the 2.5% glucose +2.5% galactose meal the median gastric retention was lower (P < 0.02) in the group fed a lactose-enriched chow (38.5%) than in the control group (41.6%). For the 5% glucose +5% galactose solution the median values were not statistically different between groups, 65.0% for the control group and 58.8% for the experimental group. The median values of the specific lactase activity in the small intestine homogenate was 0.74 U/g in the control group and 0.91 U/g in the experimental group. These values were not statistically different (P > 0.05). These results suggest that the prolonged ingestion of lactose by young adult rats changes the gastric emptying of a solution containing 5% monosaccharides. This adaptation may reflect the desensitization of intestinal nutrient receptors, possibly by an osmotic effect of lactose present in the chow.

将96只断乳雄性Wistar大鼠分为两组，分别喂食两种不同的饲料四周：一种是含有55.5%（w/w）淀粉的正常大鼠饲料（对照组，N = 48），另一种是用乳糖部分替代淀粉的大鼠饲料，使得实验组（N = 48）摄入35.5%（w/w）淀粉和20%（w/w）乳糖。然后通过测量含有乳糖（5%或10%，w/v）或葡萄糖+半乳糖（5%或10%，w/v）的四种试验餐的胃内潴留量来研究液体的胃排空情况。检测小肠匀浆的乳糖酶活性。在经口胃灌注液体餐15分钟后获得胃内潴留值。对照组5%乳糖溶液的胃内潴留中位数为37.7%，实验组为37.0%（P>0.02）。对于10%乳糖溶液，对照组和实验组的中位数分别为51.2%和47.9%（P>0.02）。然而，对于2.5%葡萄糖+2.5%半乳糖餐，喂食富含乳糖饲料的组（38.5%）的胃内潴留中位数低于对照组（41.6%）（P<0.02）。对于5%葡萄糖+5%半乳糖溶液，两组的中位数在统计学上无差异，对照组为65.0%，实验组为58.8%。小肠匀浆中特异性乳糖酶活性的中位数在对照组为0.74 U/g，在实验组为0.91 U/g。这些值在统计学上无差异（P>0.05）。这些结果表明，成年幼鼠长期摄入乳糖会改变含5%单糖溶液的胃排空。这种适应性变化可能反映了肠道营养受体的脱敏，可能是由于饲料中乳糖的渗透作用。