THE EFFECT OF INCLUDING AVOPARCIN IN THE DIET ON CELL TURNOVER AND ENZYME ACTIVITY IN THE MUCOSA OF THE RAT SMALL INTESTINE

Inclusion of avoparcin in the diet of rats resulted in a significant increase in dipeptidase activity in the mucosa of the small intestine. There was no change in the mucosal weight in the intestinal segments or in the fractional incorporation of thymidine into mucosal cells. This effect on enzyme activity may help explain some of the observations on the action of avoparcin in the small intestine. Key words: Avoparcin, small intestine, dipeptidase, rat

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Effect of Bile Acids and Other Factors on Cholesterol Uptake by Inverted Intestinal Sacs

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1958.195.3.773 ◽

1958 ◽

Vol 195 (3) ◽

pp. 773-778 ◽

Cited By ~ 6

Author(s):

Archie L. Smith ◽

C. R. Treadwell

Keyword(s):

Small Intestine ◽

Bile Acid ◽

Bile Acids ◽

Binding Sites ◽

Cellular Protein ◽

Rat Small Intestine ◽

Cholesterol Uptake ◽

Quantitative Studies ◽

Mucosal Cells ◽

Intestinal Mucosal Cells

Conditions for the use of inverted sacs of rat small intestine for quantitative studies of cholesterol uptake are described. The uptake of cholesterol by sacs did not require glucose in the incubation medium. Albumin aided cholesterol uptake but was not obligatory for this process. A binding of cholesterol to a cellular protein is proposed as the mechanism for the entrance of cholesterol into intestinal mucosal cells. Both conjugated and unconjugated bile acids inhibited cholesterol uptake possibly by blocking the binding sites of the protein responsible for cholesterol uptake. Commercial taurocholate and glycocholate contain an inhibitor of cholesterol uptake other than the bile acid.

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Regional differences of an NAD(P)H-dependent H2O2-generating enzyme activity in the rat small intestine.

ACTA HISTOCHEMICA ET CYTOCHEMICA ◽

10.1267/ahc.15.379 ◽

1982 ◽

Vol 15 (3) ◽

pp. 379-385 ◽

Cited By ~ 1

Author(s):

YOSHIMARO ISHIKAWA ◽

KEI-ICHI HIRAI ◽

KAZUO OGAWA

Keyword(s):

Enzyme Activity ◽

Small Intestine ◽

Regional Differences ◽

Rat Small Intestine

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Effect of adrenalectomy on enzyme activity in the mucous membrane of the rat small intestine

Bulletin of Experimental Biology and Medicine ◽

10.1007/bf00804359 ◽

1974 ◽

Vol 78 (5) ◽

pp. 1281-1283

Author(s):

K. Rakhimov ◽

U. Z. Kadyrov ◽

B. Zaripov

Keyword(s):

Enzyme Activity ◽

Small Intestine ◽

Mucous Membrane ◽

Rat Small Intestine

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Role of 5-HT in cholera toxin-induced mucin secretion in the rat small intestine

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1996.270.6.g1001 ◽

1996 ◽

Vol 270 (6) ◽

pp. G1001-G1009 ◽

Cited By ~ 11

Author(s):

B. A. Moore ◽

K. A. Sharkey ◽

M. Mantle

Keyword(s):

Small Intestine ◽

Receptor Antagonist ◽

Cholera Toxin ◽

Receptor Subtypes ◽

Rat Small Intestine ◽

Mucin Secretion ◽

Common Pathway ◽

Distal Small Intestine ◽

Intestinal Segments

We examined the role of 5-hydroxytryptamine (5-HT) in cholera toxin (CT)-induced mucin secretion in the proximal and distal regions of the rat small intestine. Neither the 5-HT2 receptor antagonist ketanserin nor the cyclooxygenase inhibitor indomethacin was capable of inhibiting choleraic mucin secretion. However, in the presence of the mixed 5-HT3/4 receptor antagonist tropisetron at doses that block both receptor subtypes, the secretory response was reduced to baseline levels in the proximal and distal small intestine. The selective 5-HT3 receptor antagonist ondansetron had no significant effect. These findings suggest that choleraic mucin secretion is mediated primarily through the activation of a 5-HT4-like receptor. Mucin secretion in response to the exogenous application of 5-HT occurs via two pathways: one is mediated by a 5-HT4-like receptor and is capsaicin sensitive but tetrodotoxin (TTX) insensitive, and one lacks the capsaicin-sensitive 5-HT4-mediated response but is TTX sensitive. Both converge on a common pathway that is cholinergic. No significant differences were observed between proximal and distal intestinal segments.

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Tryptophan 5-hydroxylase in rat intestine

Biochemical Journal ◽

10.1042/bj1310375 ◽

1973 ◽

Vol 131 (2) ◽

pp. 375-380 ◽

Cited By ~ 15

Author(s):

T. Noguchi ◽

M. Nishino ◽

R. Kido

Keyword(s):

Enzyme Activity ◽

Small Intestine ◽

Physiological Significance ◽

Rat Small Intestine ◽

Rat Intestine ◽

Ph Optimum ◽

Full Activity

Tryptophan 5-hydroxylase was partially purified from rat small intestine and characterized. The enzyme activity was mainly localized in the distal one-fourth of the small intestine. The enzyme required Fe2+, 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine and oxygen for full activity. The pH optimum of the reaction was 8.0. The hydroxylation rate of d-tryptophan by the enzyme was one-third that of l-tryptophan. l-Phenylalanine and l-tyrosine could not serve as substrates. The physiological significance of the enzyme is discussed.

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