Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major products of intraluminal hydrolysis of dietary proteins appear to be small peptides and amino acids. Recent studies indicate that the distal part of the small intestine may play an important role in the digestion and absorption of dietary proteins. Intestinal mucosal cellular hydrolysis of peptides and proteins represents the terminal stage of digestion of dietary proteins and appears to be carried out predominantly by amino-oligopeptidases in brush border membranes and cytoplasm. These enzymes in the two main subcellular loci are distinct since they exhibit different electrophoretic mobilities, physicochemical properties, substrate specificities and responses to starvation and dietary manipulation. Two amino-oligopeptidases have been purified from the intestinal brush border of the rat. The enzymes are remarkably similar to each other in many respects. They have an apparent molecular weight of 280 000 and are composed of two subunits of equal molecular weight. Both enzymes are glycoproteins having similar chemical compositions, common antigenic properties, substrate specificities and kinetic properties.
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PMID:Intestinal mucosal hydrolysis of proteins and peptides. 24 82

Starvation for 48 hrs reduced the activity of sucrase referred to unit length in rat proximal small intestine by approximately 30%, irrespective of whe her mucosal scrapings, isolated villus epithelial cells or brush border membranes were investigated. Sucrase activity referred to unit weight, unit protein or to unit DNA of intestinal epithelium did not change.
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PMID:Starvation and sucrose activity in small intestinal mucosa. An evaluation of different tissue preparations and reference systems. 68 56

Studies on the surface area of microvilli (MV), fluidity of brush border membranes (BBM) and D-glucose uptake were carried out in rat intestinal epithelial cells (IEC) during progressive starvation and under re-feed conditions. The surface area of MV, fluidity of BBM and D-glucose transport through IEC membranes showed an increase during starvation when compared to well-fed controls. Re-feeding experiments restored the control values of all the three parameters within a short time. The results showed that the increase in D-glucose transport through IEC membranes during starvation is due to increased surface area of MV and increased fluidity of BBM.
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PMID:Effect of starvation on glucose transport and membrane fluidity in rat intestinal epithelial cells. 155 54

The effects of long-term starvation on the activities of sucrase, lactase, and aminopeptidase, and on their respective mRNA were determined in the small intestine of thyroidectomized and sham-operated adult rats. Thyroidectomy reduced the protein loss at the level of the intestinal brush border membranes during starvation. Prolonged fasting caused a significant decrease in sucrase activity, but thyroidectomy partly prevented this effect. However, the amount of the corresponding mRNA dropped during long term starvation without incidence of thyroidectomy. Lactase activity in the brush border membranes was increased by starvation, and thyroidectomy caused a further elevation of the enzyme activity. Simultaneously, lactase mRNA content rose only slightly compared to the enzyme activity. Aminopeptidase activity and mRNA content decreased during starvation and thyroidectomy did not prevent this process. These results indicate that intestinal hydrolases respond non-coordinately to long-term food deprivation. In addition, the thyroid status of the animals has a direct influence on the adaptation of several brush border hydrolases to starvation. This suggests that the drop in plasma thyroid hormones during fasting allows a better maintenance of protein content and of hydrolase activities in the brush border membranes of the small intestine. These adaptive processes seemed to be partly controlled at a post-transcriptional level.
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PMID:Adaptation of intestinal hydrolases to starvation in rats: effect of thyroid function. 193 43

In order to examine the involvement of insulin in the activity of Na+/glucose cotransporter in rat small intestine, we compared Na(+)-dependent uptake of D-glucose by brush-border membrane vesicles prepared from control, streptozotocin-induced diabetic, insulin-treated diabetic and starved diabetic rats. In four groups, the uptake of D-glucose showed a transient overshoot in the presence of Na+ gradient between medium and vesicles (medium greater than vesicles). The overshoot magnitude was increased (1.8-fold of controls) in diabetic brush border membrane vesicles and recovered to the control level by the treatment of diabetic rats with insulin. In contrast, increased uptake of D-glucose in diabetic rats was not recovered by the starvation of diabetic rats although the blood glucose level was the same as that of controls. Furthermore, we attempted to examine phlorizin binding activities among four groups. Scatchard analysis indicated that phlorizin binding to diabetic brush border membrane vesicles was increased (1.6-fold of controls) without a change of the affinity for phlorizin as compared with controls. Increased binding of phlorizin to diabetic brush border membrane vesicles was also recovered to the control level by the treatment of diabetic rats with insulin, but not by starvation. These results suggested that the increased activity of Na+/glucose cotransporter in diabetic rats was due to the increase of the number of cotransporter and that intestinal cotransporter was physiologically controlled by insulin, but not by blood glucose levels.
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PMID:Insulin regulates Na+/glucose cotransporter activity in rat small intestine. 201 65

The effects of starvation (72 h) and refeeding with three liquid diets, differing only in the molecular form of the nitrogen source (whole whey proteins, WP; tryptic whey protein hydrolysate, WPH; and amino acid mixture, AAM), on the jejunal mucosal morphology and brush border enzyme activities (sucrase, S; maltase, M; and neutral aminopeptidase, NA) of male Wistar rats were studied. All three diets produced repair of the fasting-induced mucosal atrophy; the WP diet gave the most rapid growth with maximum villus height (VH) and protein content after 48 h (p less than 0.01). AAM gave the fastest and greatest stimulation of sucrase and maltase activities (p less than 0.01). There were no significant differences in NA activity. In control rats the WPH and AAM diets produced significantly greater villus height and disaccharidase activities than did the WP diet. Jejunal morphology and disaccharidase activities can be modified by the molecular form of alimentary protein and nutritional status interferes with these modifications.
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PMID:Dietary whey proteins and their peptides or amino acids: effects on the jejunal mucosa of starved rats. 264 93

Adult rats starved for 48 h received a daily injection of thyroxine over a 3-day period before they were killed. When compared to nourished animals, starvation provoked a 4- to 5-fold increase in immunoreactive lactase protein, which paralleled a similar stimulation of lactase activity in the brush border membranes of the proximal jejunum. Exogenous thyroxine completely inhibited the starvation-induced increase in immunoreactive lactase protein in both the intracellular and the brush border membranes.
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PMID:Modulation by thyroxine of the amount of lactase protein in the jejunum of adult rats. 310 Feb 92

Effects of diet, hibernation and seasonal variations on hydrolase activities were determined in mucosa and purified brush border membranes of the small intestine of European hamsters. Wild hamsters captured in April and fed for several weeks with an equilibrated laboratory chow (20% protein, 50% carbohydrates) exhibited a rise in disaccharidase activities (sucrase, isomaltase, lactase) but no changes in aminopeptidase N activity. During deep hibernation, in contrast to sucrase and isomaltase activities which showed only minor changes, lactase activity was significantly enhanced along the jejunoileum, and aminopeptidase N activity was maximum in the ileum. After a short period (48 h) of wakefulness and feeding following 10 days of starvation during the hibernation period, the activities of the disaccharidases and of aminopeptidase N returned to values measured in active animals. In contrast to the nutritional state, which has an important impact on the activities of intestinal enzymes, season has little effect on the intestine of the active animal under a controlled environment. The pattern of enzyme activities which occurs along the small intestine in the hibernating animal may be a prerequisite for optimum digestion during the short phases of waking during the hibernation period of the European hamster.
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PMID:Adaptation of intestinal enzymes to seasonal and dietary changes in a hibernator: the European hamster (Cricetus cricetus). 317 Aug 22

Broiler chicks, 3 to 4 wk of age, were inoculated with either Eimeria acervulina or E. mitis, and mucosal dry weights, brush border enzyme activities, and carotenoid contents as well as plasma carotenoid levels were measured at 3, 5, and 7 days postinoculation (PI). At 5 and 7 days PI mucosal dry weights, brush border enzyme activities, and carotenoid contents were significantly decreased at primary sites of infection (duodenum, E. acervulina; lower small intestine, E. mitis). In contrast, at sites remote from infection, mucosal dry weights and brush border enzyme activities were significantly increased above control values. However, mucosal carotenoid contents were significantly decreased. Between 5 and 7 days PI mucosal renewal as signalled by increases in dry weight was accompanied by increases in brush border enzyme activities. However, mucosal carotenoid contents were further decreased. High correlations were found between plasma carotenoid levels and total mucosal carotenoids in control and coccidia-infected chicks, but not in 48-h-starved chicks. Infection with coccidia increased this correlation, and the increase with E. acervulina infection was significant. These data indicate that hyperplastic and renewing mucosal tissue is defective in absorbing carotenoids, and further, that there is no direct relationship between mucosal carotenoid content and brush border enzyme activities. Apparently carotenoids are not mobilized from body depots during the first week of coccidial infections as they are during 48-h starvation.
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PMID:Physiological responses of chicken gut tissue to coccidial infection: comparative effects of Eimeria acervulina and Eimeria mitis on mucosal mass, carotenoid content, and brush border enzyme activity. 368 53

In the adult rat, starvation during 48 hours led to a three fold increase of lactase specific activity in the intestinal brush border membranes. Thyroxine injection during the three days before death (0.5 micrograms/g daily) inhibited the stimulation of lactase activity induced by starvation without modifying sucrase activity whereas hydrocortisone injections (25 micrograms/g daily) or thyroidectomy did not modify the stimulatory effect of starvation on lactase activity. These results suggests a specific hormonal control of intestinal lactase activity in the rat.
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PMID:Lactase activity is under hormonal control in the intestine of adult rat. 640 6


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