RESUMEN
A series of bezafibrate ester prodrugs 1-7 were synthesized and evaluated for hypolipidemic activity in Swiss Albino mice (SAM). Bezafibrate (1a), a hypolipidemic drug was used as a reference compound for data comparison. Among the synthesized compounds, prodrug 7 showed superior activities in decreasing triglyceride up to 30% in mice plasma after oral administration of 50mg/kg/day for 8 days. Prodrugs 2, 3, 5, 6, and 7 were found to be more lipophilic than bezafibrate (1a), indicated by partition coefficients measured in octanol-buffer system at pH 7.4. On the basis of in vivo studies, prodrug 7 emerged as new potent hypolipidemic agent.
Asunto(s)
Bezafibrato/análogos & derivados , Bezafibrato/síntesis química , Hipolipemiantes/síntesis química , Profármacos/síntesis química , Administración Oral , Animales , Bezafibrato/farmacología , Esquema de Medicación , Estabilidad de Medicamentos , Ésteres , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Hipolipemiantes/farmacología , Masculino , Ratones , Octanoles , Profármacos/farmacología , Relación Estructura-Actividad , Triglicéridos/sangre , AguaRESUMEN
The first peroxisome proliferator-activated receptor (PPAR) was cloned in 1990 by Issemann and Green. Many studies have reported the importance of this receptor in the control of gene expression of enzymes involved in lipid metabolic pathways including mitochondrial and peroxisomal fatty acid beta-oxidation, lipoprotein structure [apolipoprotein (apo) A2, apo CIII], and fatty acid synthase. By using radiolabeled molecules, it was shown that peroxisome proliferators bind and activate PPAR. As an alternative method, we developed a fluorescent dansyl (1-dimethylaminonaphthalene-5-sulfonyl) derivative peroxisome proliferator from bezafibrate (DNS-X), a hypolipidemic agent that exhibits an in vitro peroxisome proliferative activity on rat Fao-hepatic derived cultured cells. However, until now, the effect of this new compound on the liver of animals and subcellular localization was unknown. In addition to in vivo rat studies, we present a more efficient large-scale technique of DNS-X purification. Treating rats (DNS-X in the diet at 0.3% w/w) for 6 d leads to a hepatomegaly and a marked increase in liver peroxisomal palmitoyl-CoA oxidase activity. We also developed a method to localize and quantify DNS-X in tissues or cell compartment organelles. The primarily cytosolic distribution of DNS-X was confirmed by direct visualization using fluorescence microscopy of cultured Fao cells. Finally, transfection assay demonstrated that DNS-X enhanced the PPAR alpha activity as well as other peroxisome proliferators do.
Asunto(s)
Bezafibrato/química , Ácidos Grasos/metabolismo , Colorantes Fluorescentes/química , Oxígeno/metabolismo , Animales , Bezafibrato/análogos & derivados , Bezafibrato/farmacología , División Celular , Células Cultivadas , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Citosol/metabolismo , Hepatomegalia , Cinética , Hígado/citología , Hígado/enzimología , Espectroscopía de Resonancia Magnética , Masculino , Microscopía Fluorescente , Microscopía de Contraste de Fase , Modelos Químicos , Oxidorreductasas/metabolismo , Proliferadores de Peroxisomas/metabolismo , Peroxisomas/enzimología , Plásmidos , Ratas , Ratas Wistar , Receptores Citoplasmáticos y Nucleares/metabolismo , Factores de Tiempo , Volumetría , Factores de Transcripción/metabolismo , Transfección , Células Tumorales CultivadasRESUMEN
To detect the cellular sites which directly interact with peroxisome proliferators (PPs) and mediate their inducing effect on peroxisomal enzymes in rat hepatocytes, two kinds of radiolabeled ligands, AD12 (7alpha-N-(4-azido-2-hydroxy-5-iodo[125I]benzyl)-aminomethyl-5-and rostene-3beta-ol-17-one-O-3-sulfate) and BZ5 (2-[p-[2-(4'-azido-3',5'-diiodo[125I]benzamido-2'-hydroxy)ethyl]phenoxy] -2-methylpropionic acid), were developed for photoaffinity labeling. These compounds were derivatives of dehydroepiandrosterone sulfate (DHEAS) and bezafibrate, respectively, with an azido group as the photoreactive functional group. Upon UV-irradiation following incubation with rat liver cytosol and nuclei, both the ligands effectively radiolabeled several proteins analyzed by SDS-polyacrylamide gel electrophoresis/radioluminography. When [125I]AD12 was used at a concentration of 0.2 microM, two cytosolic proteins with molecular masses of 55 and 28 kDa and a nuclear protein of 40 kDa were specifically labeled, as coincubation with a 1000-fold excess of DHEAS inhibited labeling. Photoaffinity labeling of the cytosolic 28-kDa protein was also affected by Wy-14,643, but not by unsulfated dehydroepiandrosterone or androsterone sulfate, consistent with our previous findings obtained in competitive binding studies of [3H]DHEAS-binding detected in rat liver cytosol (Yamada et al. (1994) Biochim. Biophys. Acta 1224, 139-146). On the other hand, [125I]BZ5 specifically labeled a cytosolic protein of 31 kDa, which was inhibited by coincubation with bezafibrate, clofibric acid and Wy-14,643, but not with DHEAS. Thus, [125I]AD12 and [125I]BZ5 labeled several proteins which recognized DHEAS and bezafibrate, respectively, in rat liver cytosol and nuclei, providing a useful means to investigate PP-binding proteins.