Development Of Disaccharidases Research Articles

Delayed disaccharidase development in a rabbit model of intrauterine growth retardation.

Intrauterine growth retardation (IUGR) affects almost 10% of infants born in the United States. It may be responsible for delayed gastrointestinal function and is an important cause of perinatal morbidity and mortality. The New Zealand White rabbit provides an optimal model for the study of naturally occurring IUGR. At term, birth weight is determined by fetal position within the bicornuate uterus. The small intestinal disaccharidase enzymes are indicators of bowel maturity and function. To examine potential differences in disaccharidase development between normal and IUGR fetuses, this rabbit model was investigated. Jejunum was harvested at multiple stages in rabbit development including the third trimester fetus, neonate, and adult. Lactase, maltase, and sucrase enzyme activity, as well as total protein content, was determined. Results were analyzed by the 2-tailed t test and ANOVA. Lactase activity appeared in the mid-third trimester, peaked in the early neonatal period, then declined to adult levels. Maltase activity appeared in the early third trimester and gradually rose to adult levels. Sucrase remained at trace levels until the mid-neonatal period, reaching adult levels by weaning. Both lactase and maltase activity were depressed in IUGR fetuses compared with their normal littermates. This pattern of disaccharidase depression continued into the neonatal period until catch-up growth occurred at 2 wk when levels equalized. This report describes differential small intestinal disaccharidase development between normal and growth-retarded rabbit fetuses in a naturally occurring model of IUGR.

Precocious development of disaccharidases in the baboon intestine

Precocious development of disaccharidases in the baboon intestine

Orally administered spermine induces precocious intestinal maturation of macromolecular transport and disaccharidase development in suckling rats

The effect of orally administered spermine on intestinal cessation in bovine IgG transport and digestive enzymes in the small intestine was examined in the suckling rats. By the repeated oral administration of spermine (0.1 or 0.25 μmol/g bwt) for 5 days, the ratio of protein to DNA was significantly increased. Maltase and lactase activities changed dose dependently in the spermine treated pups. Absorption of bovine IgG transport in the intestine was dose dependently depressed by spermine treatments. Morphological inspection of treated pups showed a decline in the number of epithelial cells that absorb bovine IgG and in their vesicle sizes from basal to upper regions of the villi. The ratio of mitosis in the crypt of treated pups significantly increased in the small intestine and cecum. These results suggest that exogenously administered spermine induces precocious maturation of the macromolecular transmission and disaccharidase activity in the small intestine of the suckling rats.

Effect of Prenatal Dexamethasone Administration: Fetal Rabbit Intestinal Nutrient Uptake and Disaccharidase Development

To examine the effect of prenatal steroids on fetal intestinal maturation, eight pregnant rabbits received either dexamethasone (Dex) or saline (Cont) on Days 25-27 of a 31-day gestation. As the rabbit provides a model of growth retardation based on uterine position, fetuses were identified as favored (Fav) or runt(Runt), generating four study groups: ContFav, ContRunt, DexFav, and DexRunt. On Day 31 the small intestinal uptake of glucose and proline was measured by an everted sleeve technique. Additionally, lactase and maltase activity was determined. Small intestinal length and nutrient uptake was significantly increased in the Dex fetuses. Control runts had a trend to decreased levels of nutrient uptake when compared to their favored counterparts. This trend reversed in the Dex fetuses with runt nutrient uptake surpassing that of the favored fetus. A trend to increased enzyme activity of both lactase and maltase was demonstrated. This report provides the first description of maternal steroid administration causing a marked increase in fetal small intestinal length and glucose and praline absorption in an in vivo model of intrauterine growth retardation.

Effect of esophageal ligation on the development of fetal rabbit intestinal lactase

To investigate the effect of normal fetal swallowing and amniotic fluid ingestion on small intestinal disaccharidase development, 13 pregnant New Zealand White rabbits underwent operation on day 24 of a normal 31-day gestation. The right ovarian fetus in the bicomuate uterus underwent esophageal ligation (EL), while the contralateral left fetus underwent cervical exploration only, and served as the control (C). Rabbits were sacrificed on gestational day 31, fetal somatic measurements obtained, and the midjejunum removed for determination of disaccharidase activity and protein content. There was one maternal death, and 9 of 12 fetal pairs survived the entire study period (75%). Results are reported as mean ± SEM, analyzed by two-tailed Student's t testing with P < .05 being considered significant. Fetal weight was decreased in EL (48.6 ± 2.7 g) versus C (51.4 ± 3.2 g) ( P = .06). Small intestinal length decreased in EL (49.2 ± 2.0 cm) versus C (54.9 ± 1.1 cm) ( P = .01). Midjejunal protein content (mg/mL homogenate) was also significantly decreased in EL (38.4 ± 3.4) versus C (46.2 ± 3.7) ( P = .05). Sucrase activity was not detectable in either group. Lactase activity in jejunal mucosa was not effected when expressed as units of enzyme per milliliter of homogenate (EL = 0.357 ± 0.03 v C = 0.373 ± 0.04; P = .70) and units enzyme per gram of protein (EL = 38.8 ± 4.2 v C = 34.2 ± 4.6; P = .44). We have confirmed previous studies demonstrating decreases in somatic growth, small intestinal length, and mucosal nutrient transport in rabbit fetuses following esophageal ligation. The present study demonstrates, in contrast, that the brush border disaccharidase lactase develops independently of the normal fetal swallowing mechanism with the concomitant ingestion of amniotic fluid. Implications for infants with intestinal atresias are under investigation.

Effect of transamniotic administration of epidermal growth factor on fetal rabbit small intestinal nutrient transport and disaccharidase development

As fetal swallowing is documented in utero, supplementation of the ingested amniotic fluid with nutrients or hormones has been postulated as a potential prenatal treatment for intrauterine growth retardation (IUGR). To study the effect of epidermal growth factor (EGF) on the developing fetal small intestine, 12 pregnant rabbits underwent operation on day 24 of a normal 31-day gestation. Bilateral ovarian end fetuses underwent catheterization of their respective amniotic cavities with attachment to a miniosmotic pump. Study fetuses received recombinant human EGF at approximately 300 micrograms/kg/d for 1 week; controls received carrier solution only at an equivalent rate. On gestational day 31, fetuses were delivered by cesarean section and somatic measurements were recorded. The small intestine was harvested and proximal, middle, and distal regions were analyzed for lactase and maltase enzyme activity. Additionally, the uptake of radiolabeled glucose and proline was measured by a standard everted mucosal sleeve technique for each segment. Results were analyzed by Student's paired t test and reported as mean +/- SEM. Nine fetal pairs survived (75%). Small intestinal (SI) length was increased in EGF fetuses (54.8 +/- 1.9 cm) versus control (50.4 +/- 2.7 cm) (P = .02). Lactase activity, reported as UE/g protein, was significantly increased in the proximal segments in the EGF-infused fetuses; maltase was significantly increased in both the proximal and middle segments (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Precocious cessation of intestinal macromolecular transport by synthetic trypsin inhibitor in suckling rats.

The effects of repeated oral administration of the synthetic trypsin inhibitor camostat on intestinal macromolecular transport and disaccharidase development were investigated in suckling rats. By daily treatment with camostat, bovine immunoglobulin (Ig) G transport in the intestine declined more rapidly in treated than in control rats. The absorption curve shifted to the left in treated rats 3 days before the controls. Morphological inspection of treated pups showed a decline in the number of epithelial cells that absorb bovine IgG and in their vesicle size from basal to upper regions of the villi. Maltase activity precociously increased with camostat treatment. Chronic subcutaneous injection of camostat did not cause any changes in IgG transport and maltase activity. The depression of IgG transport by oral treatment with camostat was not affected by the cholecystokinin (CCK) receptor antagonist L 364718 and was not inhibited by adrenalectomy. The absorptive responses of IgG and maltase activity were not affected by CCK-8 treatment. These data indicate that oral administration of camostat induces precocious maturation of the small intestine and that the effect is not mediated via endogenous CCK released by camostat.

Development of Disaccharidases and Lysosomal Enzymes

Development of Disaccharidases and Lysosomal Enzymes

Effect of diet on disaccharidase activity in the chick.

1. The influence of diets, particularly dietary carbohydrate, on the development of the intestinal disaccharidases of the chick was studied.2. The maltase activity in the small intestine was similar in groups of 25-d-old chicks that had been fed, from hatching, on diets containing either starch, glucose, maltose, sucrose, or a mixture of 50% glucose + 50% lactose, as the source of carbohydrate. The sucrase activity in the small intestine was also similar in the different groups, as was the palatinase (the enzyme that hydrolyses palatinose, i.e. 6-o-α-D-glucopyranosyl-D-fructose) activity. The maltase activity in the large intestine of the group receiving the starch-containing diet was significantly increased. The lactase activity in the large intestine was significantly higher in the group receiving the 50% glucose + 50% lactose and in the group receiving glucose than in the other groups. Body- weights were similar with all the diets.3. The fasting of chicks for a period of 3 d caused a marked decrease in the activity of the disaccharidases and in the protein content of the homogenates of the small intestine.4. The maltase activity was similar in the small intestine of chicks that had been fasted for 3 d and subsequently given diets containing either starch, glucose, maltose, sucrose or fructose for 5 d. The sucrase activity, the isomaltase activity and the palatinase activity were also similar in the small intestine of the chicks given the different diets. Feeding with a fat-free or protein-free diet did not affect the development of disaccharidases in the small intestine, but feeding with a carbohydrate-free diet resulted in reduced disaccharidase activity.5. The results suggest that, in the chick, dietary carbohydrate is necessary for the development of the disaccharidases but the form of the carbohydrate is not important. None of the sugars tested had a specific effect on a particular disaccharidase.

Intestinal disaccharidase activity in a monotreme and eight species of marsupials (with an added note on the disaccharidases of five species of sea birds)

1. 1. The monotreme ( Tachyglossus aculeatus) had levels of activity of maltase, isomaltase and trehalase which were similar to those found in man and other placental mammals. By contrast, trace levels only of lactase and cellobiase were found. Sucrase was completely absent., 2. 2. Most marsupials had all the above disaccharidase activities and at similar levels to those found in the placental mammals. Notable exceptions were the absence of sucrase in the kangroo ( Macropus giganteus) and in the short-nosed bandicoot ( Isoodon obeselus) and the extremely low trehalase activity in the koala ( Phascolarctos). 3. 3. Similarities in presence and development of disaccharidases in the kangaroo, which has a ruminant-like digestive system, and the placental ruminants were noted. 4. 4. Maltase, sucrase and lactase activities in five species of sea bird were found to be very low by comparison with most mammals.