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Query: HUMANGGP:036187 (gut)
 73,132 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of pituitary hormones on intestinal adaptation to small bowel resection was studied by examining jejunal and ileal structure and function in control and in sham-operated rats, and in animals with 50% proximal or distal resection which were divided into three main groups: normally-fed, hypophysectomized. and pair-fed. The pituitary was removed 2 weeks before intestinal surgery and gut structure and function were studied 4 weeks later. The effectiveness of hypophysectomy was confirmed by histological examination of the aspirated pituitary, and by showing a significant subsequent reduction in weight of the testes and adrenals. Food intake and body weight fell significantly after removing the pituitary; intestinal surgery caused a transient further decrease in food intake. Measurements of intestinal villus height and crypt depth, indices of mucosal mass (mucosal wet weight, protein and DNA content/cm intestine), measurements of mucosal alpha-glucosidase activity, and in vivo galactose absorption/unit length of intestine all showed comparable results. In rats with an intact intestine, resection resulted in mucosal hyperplasia and increased segmental absorption. Following hypophysectomy, there was marked mucosal hypoplasia and hypofunction which seemed to be due largely to associated hypophagia since comparable changes were found in the pair-fed, sham-operated rats. However following pituitary removal, both distal jejunum and proximal ileum retained their capacity to regenerate though the magnitude of this adaptive change was much greater in the resected, pair-fed rats suggesting that hypophagia alone cannot explain the diminished adaptation to resection after hypophysectomy. By inference, pituitary hormones do influence the adaptive response to resection.
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PMID:Pituitary hormones and the small bowel: effect of hypophysectomy on intestinal adaptation to small bowel resection in the rat. 11 42

The effects of deoxycholate, taurocholate and cholate on transport and mucosal ATPase activity have been investigated in the rat jejunum in vivo using closed-loop and perfusion techniques. In the closed-loops, 5 mM deoxycholate selectively inactivated (Na+ + K+)-ATPase, and net secretion of Na+ induced by 2.5 mM deoxycholate was due to reduced lumen to plasma flux of the ion; deoxycholate (2.5 mM) produced marked inhibition of 3-0-methylglucose transport. Luminal disappearance rates of deoxycholate (60.5 plus or minus 2.9% per g wet st of gut) greatly exceeded those of taurocholate (4.3 plus or minus 1.0). In the perfusion studies 1 mM deoxycholate induced net secretion of water, Na+ and C1-, and inhibited active glucose transport; concomitantly "total" ATPase, (Na+ + K+)-ATPase, and Mg-2+-ATPase were inhibited. At higher concentrations (5 mM) deoxycholate stimulated Mg-2+-ATPase activity. Taurocholate and cholate at 1mM had no effect on transport of (Na+ + K+)-ATPase. Mucosal lactase, sucrase and maltase activities were not affected by 1 mM deoxycholate, taurocholate or cholate. These results suggest that deoxycholate inhibits sodium-coupled glucose transport by inhibition of (Na+ + K+)-ATPase at the lateral and basal membranes of the epithelial cell, rather than from an effect at the brush-border membrane level.
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PMID:A comparative study on the effects of different bile salts on mucosal ATPase and transport in the rat jejunum in vivo. 12 87

At an average of 32 days after a modified Roux-en-y repositioning of rat small intestine, the mucosal mass, mucosal composition, in vivo absorption of galactose and the activity of maltase, sucrase and alkaline phosphatase were measured. In the gut segment with digestive secretions but without food (A) the only change was a decrease of sucrase activity which occurred most probably at the cellular level. In the gut segment with food and gastric juice and a reflux of digestive secretions (B) complex changes took place. An increase in mucosal mass was not accompanied by an increase in galactose absorption. There was a high increase of sucrase activity, a moderate increase of maltase activity and a tendency of the alkaline phosphatase activity to decrease. The changes (increase in mucosal mass and total enzyme activity, but no changes in activity at the cellular level) in the segment exposed to both digestive secretions and food (C) were compatible with a more proximal promotion of a distal gut segment.
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PMID:An experimental model for studies on the effects of food and digestive secretions on the digestive-absorptive capacity of rat small intestine. 89 9

Activities of the small intestinal mucosal enzymes lactase, sucrase, maltase, alkaline phosphatase and N-acetyl-beta-glucosaminidase were studied in rats with surgically-induced upper intestinal stasis and in control animals. The first four are brush border enzymes, the latter a lysosomal enzyme. There was a reduction in the activities of all enzymes in the operated animals. The change lining was significant and most marked in mucosa the blind loop and gut distal to it; areas in which there is gross bacterial overgrowth and excessive levels of intraluminal deconjugated bile salts. The significance of these findings in relation to malabsorption consequent on bacterial contamination of the upper gut is uncertain and requires further study.
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PMID:Effect of stasis on intestinal enzyme activities. 105 24

Acarbose, an alpha-glucosidase inhibitor, delays absorption of carbohydrate in the gut, thereby lowering postprandial glucose levels. Safety data on this drug have been gathered in a series of studies on animals and in extensive clinical trials in humans. Although an initial long term feeding study in rats showed an excess of renal tumours at very high dosages of acarbose (up to 300 mg/kg bodyweight daily), further evaluation with similar studies in rats, hamsters, and dogs indicated that the problem was related to carbohydrate malabsorption. With adequate glucose intake and in gavage studies, no difference in tumour incidence between placebo- and acarbose-treated groups was seen. From 1976 to 1989, safety data on acarbose were obtained in approximately 8800 patients in 2 separate groups of clinical trials, the Bayer International Clinical Data Pool and the American phase III trials. Almost all adverse experiences, as reported by 56 to 76% of patients on acarbose vs 32 to 37% of patients on placebo, were related to the digestive system and included diarrhoea, flatulence, bloating and nausea. Most symptoms were of mild to moderate intensity and tended to improve with time. In the American trials a small but significant increase in liver transaminases was seen, 3.8% in acarbose-treated patients vs 0.9% in controls together with a 1% increase in anaemia in the acarbose group. Overall, acarbose was well tolerated and the adverse experience profile was clinically acceptable.
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PMID:Safety profile of acarbose, an alpha-glucosidase inhibitor. 128 May 77

Ascorbic acid 2-O-alpha-glucoside (AA-2G) has been reported to have antiscorbutic activity in guinea pigs. The present experiments examined the metabolic fate of AA-2G following ingestion. Oral administration of AA-2G (96 mg) to guinea pigs resulted in a remarkable increase of ascorbic acid in various tissues as well as plasma, but intact AA-2G was detected only in plasma, but intact AA-2G was detected only in plasma and urine in small amounts. The absorption efficiency of AA-2G and ascorbic acid was further determined by using everted gut sacs of rats. Ascorbic acid released from AA-2G on the mucosal side was effectively taken up across intestinal membranes into the serosal side, whereas AA-2G poorly permeated via a passive transport system. The hydrolysis of AA-2G on the mucosal surface of everted gut was completely inhibited by an alpha-glucosidase inhibitor and the hydrolytic activity of a crude membrane extract diminished to one-forth after immunoprecipitation with the antibody specific to maltase. From these results, it is concluded that ingested AA-2G serves as a vitamin C source through the hydrolysis by intestinal membrane-bound alpha-glucosidase, mainly maltase, and the subsequent absorption of released ascorbic acid.
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PMID:Evaluation of ascorbic acid 2-O-alpha-glucoside as vitamin C source: mode of intestinal hydrolysis and absorption following oral administration. 129 35

The effect of bombesin on the postnatal development of the gastrointestinal tract was examined in New Zealand white rabbits. Bombesin (1.25, 12.5, 30 micrograms/kg body weight) or vehicle was administered intraperitoneally to suckling rabbits for 13 days starting on day 4 of life. The animals were killed at day 17. There was no significant effect of bombesin at doses of 1.25 or 12.5 micrograms/kg in any region of the gut studied. Bombesin administered at 30 micrograms/kg induced a widespread trophic effect in the gastrointestinal tract characterized by significant increases in the wet weight of the stomach, liver and whole small intestine, as well as in 10-cm segments of the proximal, middle, and distal small intestine. There was also a significant increase in the mucosal weight of 10-cm segments of the proximal, middle and distal small intestine, and the colon in the bombesin-treated group. Bombesin significantly increased the protein and DNA contents of the liver, the fundus of stomach, all segments of the small intestine and the distal colon. Maximal stimulation was seen in DNA content, suggesting that bombesin has a primarily hyperplastic effect. Bombesin increased the activities of small intestinal sucrase and maltase but not lactase. Bombesin did not alter hepatic glucokinase activity. These findings suggest that bombesin can promote the growth of the neonatal rabbit gastrointestinal tract and liver.
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PMID:Effect of bombesin on the development of the neonatal rabbit gastrointestinal tract. 156 36

To investigate the mechanism of oral carbohydrate-stimulated secretion of the two most potent incretin candidates, gastric inhibitory polypeptide (GIP) and truncated glucagon-like peptide-1 (tGLP-1), we studied the changes in the plasma levels of these peptides in five healthy men after sucrose ingestion with or without pretreatment with an alpha-D-glucosidase inhibitor (AO-128). After sucrose ingestion, plasma levels of GIP peaked at 15 min and remained high up to 120 min. Plasma levels of GLP-1 NT measured with antiserum R1043 (N-terminal specific) tended to decrease gradually and those of GLP-1 CT measured with antiserum R2337 (C-terminal specific) increased. Therefore, estimated plasma levels of tGLP-1 increased markedly within 30 min, then declined slightly over the next 60 min. After treatment with AO-128 (0.6 mg/day) for 1 week, increases in plasma glucose and insulin levels were attenuated and the increase in plasma GIP levels was diminished, while the increase in tGLP-1 levels was sustained much longer. It is concluded that GIP secretion is stimulated by glucose absorption and tGLP-1 secretion by the presence of sucrose in the gut.
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PMID:Differences in glucagon-like peptide-1 and GIP responses following sucrose ingestion. 157 19

Previous studies have demonstrated that the specific activities of several proximal small intestinal mucosal enzymes fall in the aging rat. This reduction was due to a delay in the full expression of activity of these enzymes during epithelial cell transit from the crypt onto the intestinal villus. We now show in the ad libitum fed Fischer 344 rat that jejunal sucrase, maltase, and alkaline phosphatase specific activities do not fall gradually throughout the life span, but are reduced during senescence. Caloric restriction to 60% of ad libitum intake (DR) abolishes or delays this fall in enzyme activity. Jejunal mucosal immunoprecipitable sucrase-isomaltase (S-I) content also falls with age, but sucrase specific activity per molecule of S-I is less in the older ad libitum fed (approximately 45) than in the DR rats (approximately 60). Jejunal lactase activity falls gradually throughout the life span of ad libitum and DR rats, but lactase activity consistently was higher in DR animals. These observations indicate that DR alters the age-related changes in the activity of several enzymes in the rapidly replicating gut mucosa.
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PMID:Food restriction retards age-related biochemical changes in rat small intestine. 190 40

Gastric intubation was adopted to examine the effect of continuous nutrient supply on digestive development of the pig during the immediate post-weaning period. The 14 d-weaned animals were slaughtered at 3, 5 and 7 d post-weaning (3W, 5W and 7W respectively) and the suckled animals were slaughtered at 14 and 22 d of age (14SR and 22SR respectively). The weight of the pancreas (g/kg bodyweight) was significantly greater (P less than 0.05) in the 5W and 7W groups, as was the weight of large intestine (g/kg) in all weaned groups (P less than 0.01) compared with sow-reared pigs. The stomach weight (g/kg) tended to be greater in the weaned groups. Weaning, in conjunction with a continuous nutrient supply, did not significantly alter the time-related changes in the weight of the small intestine (SI) or the SI mucosa, although both variables tended to be lowest in the 3W group. However, there was a 20% reduction in the protein content of the mucosa within the first 3 d post-weaning (P less than 0.01) which persisted during the 7 d experimental period. Lactase, (beta-galactosidase; EC 3.2.1.23) activity (mumol/g protein and mol/d) of the 7W group was reduced to approximately 40% of the 22SR value. Hence, continuous nutrient supply may have delayed, but did not prevent, the loss of lactase activity at weaning. The activity of sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) was significantly higher in 22SR compared with 14SR animals. Sucrase activity in weaned pigs was intermediate to the values for sow-reared pigs whereas maltase (alpha-glucosidase; EC 3.2.1.20) and glucoamylase (glucan 1,4-alpha-glucosidase; EC 3.2.1.3) were significantly increased in relation to their sow-reared counterparts. Continuous nutrient supply did not prevent the reduction in villous height and the crypt hypertrophy associated with weaning. The results of the present study suggest that there may be some degree of interaction between nutrient intake and gut development during the immediate post-weaning period but that there is also a component of the adaptive response which is independent of nutrient intake. They confirm the rapid substrate induction of the brush-border glucoamylases and indicate the importance of considering total as well as specific enzyme activity for satisfactory interpretation of changes in digestive function.
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PMID:Digestive development of the early-weaned pig. 1. Effect of continuous nutrient supply on the development of the digestive tract and on changes in digestive enzyme activity during the first week post-weaning. 190 70


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