Expression of the Na+ Dependent Uridine Transport System of Rabbit Small Intestine : Studies with mRNA-Injected Xenopus laevis Oocytes

Xenopus laevis oocytes were used as an expression system to prove and characterize the carrier-mediated transport of uridine in the small intestine. Significant Na+ dependency was observed for the uptake of [3H]uridine by Xenopus laevis oocytes injected with poly(A)+RNA prepared from rabbit small in...

Full description

Saved in:
Bibliographic Details
Published in:Biological & pharmaceutical bulletin 1993/05/15, Vol.16(5), pp.493-496
Main Authors: TERASAKI, Tetsuya, KADOWAKI, Atsushi, HIGASHIDA, Haruhiro, NAKAYAMA, Kohzo, TAMAI, Ikumi, TSUJI, Akira
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Carrier Proteins - biosynthesis
Carrier Proteins - metabolism
expression
Female
Fundamental and applied biological sciences. Psychology
Intestinal Mucosa - metabolism
Intestine, Small - metabolism
Intestine. Mesentery
Male
membrane transport
Microvilli - metabolism
nucleoside uptake
oocyte carrier protein
Oocytes - drug effects
Oocytes - metabolism
Poly A - metabolism
Rabbits
RNA, Messenger - pharmacology
small intestine
Sodium - metabolism
Symporters
Vertebrates: digestive system
Xenopus laevis
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Xenopus laevis oocytes were used as an expression system to prove and characterize the carrier-mediated transport of uridine in the small intestine. Significant Na+ dependency was observed for the uptake of [3H]uridine by Xenopus laevis oocytes injected with poly(A)+RNA prepared from rabbit small intestinal mucosa. By contrast, the uptake of [3H]uridine was negligible in water-injected oocytes. There was no significant difference in the Na+ dependent uptake rates of [3H]uridine among oocytes expressed by using mRNA prepared by three different methods. The uptake of [3H]uridine by mRNA-injected oocytes was enhanced by increasing the culturing time after mRNA injection. Concentration dependency for uridine transport was observed with the Michaelis constant of 8.27 μM, which was comparable to that reported in the study using the brush-border membrane vesicles from rabbit small intestine (6.4 μM). Furthermore, the uptake of [3H]uridine was significantly inhibited by adenosine and thymidine, but not by adenine and uracil. Consequently, the transport system of uridine expressed in mRNA-injected oocytes is clarified to be similar to that functioning in the brush-border membrane of the small intestine.
ISSN:0918-6158
1347-5215
DOI:10.1248/bpb.16.493