Conjugated bile acid uptake by Xenopus laevis oocytes induced by microinjection with ileal Poly A+ mRNA.
Apical membranes of ileal enterocytes contain the major Na+/bile acid cotransporter activity in mammals. Microinjection of guinea pig ileal mucosal Poly A+ mRNA (25 ng) into Xenopus oocytes resulted in 22,23-3H-cholyltaurine uptake at day 3 after injection (453 fmol/oocyte-hr), while control viral mRNA (25 ng) gave an uptake rate of 133 fmol/oocyte-hr. The transport rate increased in direct relationship to the concentration of injected mRNA, cholyltaurine, or Na+ in the incubation media. Uptake of cholyltaurine using rabbit ileal mucosal Poly A+ mRNA was 3891 fmole/oocyte-hr compared to rabbit jejunal-mucosa Poly A+ mRNA (control) injections inducing 728 fmol/oocyte-hr. Such expression of the ileal Na+/bile acid cotransporter may facilitate cloning of this key mammalian gene.
Department of Medicine, University of California, San Diego, La Jolla 92093.
S
S
Sorscher
J
J
Lillienau
J L
JL
Meinkoth
J H
JH
Steinbach
C D
CD
Schteingart
J
J
Feramisco
A F
AF
Hofmann
D000818:Animals; D001692:Biological Transport; D005260:Female; D006168:Guinea Pigs; D007082:Ileum; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000502:physiology*; D007700:Kinetics; D008845:Microinjections; D009029:Mosaic Viruses / Q000235:genetics; D009865:Oocytes / Q000378:metabolism*; D011061:Poly A / Q000008:administration & dosage / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000008:administration & dosage / Q000235:genetics* / Q000378:metabolism; D012367:RNA, Viral / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D013656:Taurocholic Acid / Q000378:metabolism*; D014982:Xenopus laevis
D012333:RNA, Messenger; D012367:RNA, Viral; D011061:Poly A; D013656:Taurocholic Acid