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Titolo:
Effect of P-glycoprotein modulators on alkaline phosphatase activity in cultured rat hepatocytes
Autore:
Calhau, C; Martel, F; Hipolito-Reis, C; Azevedo, I;
Indirizzi:
Fac Med Porto, Inst Pharmacol & Therapeut, P-4200 Oporto, Portugal Fac MedPorto Oporto Portugal P-4200 Therapeut, P-4200 Oporto, Portugal Fac Med Porto, Dept Biochem, P-4200 Oporto, Portugal Fac Med Porto Oporto Portugal P-4200 pt Biochem, P-4200 Oporto, Portugal
Titolo Testata:
CELLULAR PHYSIOLOGY AND BIOCHEMISTRY
fascicolo: 4, volume: 10, anno: 2000,
pagine: 195 - 202
SICI:
1015-8987(2000)10:4<195:EOPMOA>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
TYROSINE PHOSPHATASE; PUTATIVE INVOLVEMENT; CELL-PROLIFERATION; ATPASE ACTIVITY; PROTEIN-KINASE; HL60 CELLS; TRANSPORT; RESISTANCE; CORTICOSTERONE; LIVER;
Keywords:
P-glycoprotein; alkaline phosphatase; rat hepatocytes; organic cation transporter;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Calhau, C Fac Med Porto, Inst Pharmacol & Therapeut, P-4200 Oporto, Portugal Fac Med Porto Oporto Portugal P-4200 , P-4200 Oporto, Portugal
Citazione:
C. Calhau et al., "Effect of P-glycoprotein modulators on alkaline phosphatase activity in cultured rat hepatocytes", CELL PHYS B, 10(4), 2000, pp. 195-202

Abstract

Alkaline phosphatases (orthophosphoric-monoester phosphohydrolase, E.C. 3.1.3.1) are a group of nonspecific phosphomonoesterases located primarily inthe plasma membrane of the cells in which they occur [1]. It was recently demonstrated that alkaline phosphatase (ALP) concentrationin different tissues is positively correlated with the extent of exchange surface per unit volume of the tissue, suggesting an association between ALP and transport systems [2]. Moreover, several groups [3,4,5] obtained evidence of an involvement of ALP in the modulation of P-glycoprotein activity in hepatocytes. The aim of the present study was to determine the putative influence of compounds known to modulate P-glycoprotein-mediated transport on hepatic ALP activity, by using primary cultured rat hepatocytes. The K-m and V-max values of ALP were determined (657.2 muM (306.8-933.1) and 32.0+/-1.5 nmol mg protein(-1) min-respectively). Vanadate and corticosterone concentration-dependently reduced ALP activity, producing maximal reductions of 79% (100 muM) and 71% (100 muM), respectively. The IC50's were found to be 7.9 muM (2.1-29.5 muM) and 2.4 muM (0.2-35.2 muM), respectively. Cyclosporin A, verapamil, octreotide, kaempferol, daunomycin and genisteinproduced a concentration-dependent increase in ALP activity. ALP activity was maximally increased to 253%, 390%, 180%, 487%, 449% and 193% of controlin the presence of 100 muM cyclosporin A, 50 muM verapamil, 10 muM octreotide, 100 muM kaempferol, 100 muM daunomycin and 1 muM genistein, respectively. The results show that all P-glycoprotein modulators tested were able to significantly affect the activity of hepatic-ALP. These effects on ALP activity may contribute to the modulation of P-glycoprotein activity by these drugs. Copyright (C) 2000 S. Karger AG, Basel.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 09:50:48