Mechanism of action of cysteamine on duodenal alkaline phosphatase

Japundzić, I; Levi, E.

doi:10.1016/0006-2952(87)90521-1

Cited by 7 publications

(8 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is known that antac ids suppress mepirizole-induced duodenal ulcers as well as those provoked by cysteam ine or propionitrile [10], The effect of antac ids on mepirizole-induced DAP decrease was not examined. However, inability of antacids to prevent the decrease of DAP activity after cysteamine administration [9] allows us to suppose that the effect of the ulcerogens on DAP activity is probably inde pendent of their effect on gastric acid secre tion. Moreover, the appearance of these two effects at different times after cysteamine administration confirms the validity of our hypothesis that they need not be causally related [9], It was shown earlier that the suppression of alkaline secretion in the duodenum fol lows the administration of mepirizole in rats [11], The effect was prevented by pretreat ment with PGEy [II].…”

Section: Discussionmentioning

confidence: 99%

“…However, inability of antacids to prevent the decrease of DAP activity after cysteamine administration [9] allows us to suppose that the effect of the ulcerogens on DAP activity is probably inde pendent of their effect on gastric acid secre tion. Moreover, the appearance of these two effects at different times after cysteamine administration confirms the validity of our hypothesis that they need not be causally related [9], It was shown earlier that the suppression of alkaline secretion in the duodenum fol lows the administration of mepirizole in rats [11], The effect was prevented by pretreat ment with PGEy [II]. Inability of PGEy to prevent the decrease of DAP activity after mepirizole administration (table 3) indi cated that the two effects of mepirizole could not be causally related as well.…”

Section: Discussionmentioning

confidence: 99%

“…We have shown earlier that neither chemical (antacids) nor mechanical (pylorus ligation) prevention of HC1 disposal to duo denum was able to prevent the decrease of DAP activity after cysteamine administra tion [9], Mepirizol, which does not change HC1 secretion [10], and propionitrile. which provokes HC1 hypersecretion as well as cys teamine.…”

Section: Discussionmentioning

confidence: 99%

“…after s.c. administration of the drugs to rats. Ethanolamine affected DAP activity neither under in vivo [9] nor under in vitro conditions ( fig. 4).…”

Section: Comparative Effect O F Different Duodenal Ulcerogens On Dapmentioning

confidence: 99%

“…Among molecular changes recently dis covered [4], cysteamine was found to cause significant decrease of duodenal alkaline phosphatase (DAP) activity in rats [4,[7][8][9], The effect was detectable 4 h after a single s.c. injection of cysteamine and the decrease of DAP activity was most prominent at 12 h after the administration of the drug [9], Un der the same conditions cysteamine did not affect alkaline phosphatase activity in the liver [9]. The data indicated that the effect of the ulcerogen was oriented only to the target organ, i.e.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Effect of Duodenal Ulcerogens Mepirizole and Propionitrile on Small Intestinal and Liver Alkaline Phosphatase Activity in Rats

Japundzić¹,

Levi²,

Rakic-Stojiljkovic³

1990

Digestion

Self Cite

View full text Add to dashboard Cite

Duodenal ulcer could be induced in rats by a single subcutaneous injection of the anti-inflammatory agent mepirizole (M) or by the alkyl chemical propionitrile (P). Contrary to M, P provokes HCl hypersecretion as well. We used these animal models of duodenal ulcer to study the preulcerogenic molecular changes in the mucosal cells and their causal relationship to HCl hypersecretion. It was found that M and P induced the dose- and time-dependent decrease of duodenal alkaline phosphatase (DAP) activity. The decrease was detected at 4 h, with a nadir at 12 h after the injection of both drugs. The decrease of alkaline phosphatase activity was organ-specific after P administration and it was even regional-specific along the small intestine after M administration. At the level of mucosal cells of duodenum the effect of the ulcerogens was enzyme-selective. Both ulcerogens decreased protein and alkaline phosphatase activities; however, they had no effect on lysosomal acid phosphatase. Contrary to cysteamine (C), the effect of M and P on DAP depletion could not be reproduced under in vitro conditions. An interference of P and a slight additive effect of C on DAP depletion after simultaneous subcutaneous administration with M to the rats was found. The results indicate that the DAP depletion after in vivo administration of the three duodenal ulcerogens could be provoked by at least two different mechanisms. The decrease of DAP activity seems to be a general property of the duodenal ulcerogens independent of their effects on gastric acid secretion or on the suppression of alkaline secretion in the duodenum. As a late molecular event most probably elicited by the early morphological changes, the decrease of DAP activity could rather be related to ulcer healing than to its pathogenesis.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…after s.c. administration of the drugs to rats. Ethanolamine affected DAP activity neither under in vivo [9] nor under in vitro conditions ( fig. 4).…”

Section: Comparative Effect O F Different Duodenal Ulcerogens On Dapmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations