INVESTIGADORES
SANCHEZ POZZI Enrique Juan
artículos
Título:
Effect of Oral-Administration of Ursodeoxycholic Acid on Rat Hepatic and Intestinal UDP-Glucuronosyltransferase
Autor/es:
ENRIQUE JUAN SANCHEZ POZZI; CATANIA, VIVIANA A; LUQUITA, MARCELO G; ROMA, MARCELO G; RODRÍGUEZ GARAY, EMILIO A; MOTTINO, ALDO D
Revista:
CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY
Editorial:
NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS
Referencias:
Lugar: Otawa; Año: 1994 vol. 72 p. 1265 - 1271
ISSN:
0008-4212
Resumen:
The effect of oral administration of the bile acid ursodeoxycholic acid on rat hepatic and intestinal microsomal UDP-glucuronosyltransferase was studied. The bile acid
was administered during 8 days at a daily dose of 500 mg/kg body
weight. Enzyme activity was assessed in native and activated microsomes,
using bilirubin and p-nitrophenol as substrates. Activation was
achieved either by including UDP-N-acetylglucosamine in the incubation
mixture or by preincubating native microsomes with an optimal
concentration of Lubrol Px. Irrespective of activation status of the
microsomes, ursodeoxycholic acid
treatment increased enzyme activities toward both substrates in
intestine, but not in liver. The analysis of the degree of activation by
Lubrol Px revealed that, at least for bilirubin, ursodeoxycholic acid decreased the latency of the intestinal enzyme. The analysis of the lipid composition of microsomes showed several changes in response to ursodeoxycholic acid
in intestine but not in liver. Thus, a decrease in
cholesterol/phospholipid ratio and an increase in the unsaturation index
of total-lipid fatty acids, which correlated well with a membrane
"fluidification," were observed. These modifications appear to be
related to the lower latency of bilirubin UDP-glucuronosyltransferase
in intestine from treated rats and could be responsible, at least in
part, for the improvement of enzyme activity in this group. Whatever the
mechanism involved, the increment of intestinal UDP-glucuronosyltransferase activities toward both substrates may be relevant as a complement to the hepatic enzymes in those liver diseases in which ursodeoxycholic acid is used as a therapeutic agent.