Intrinsic factor receptor during fetal development of the human intestine.
Intrinsic factor receptor activity was observed in mucosal homogenates from whole small intestine and colon of 10-19-week fetuses, whereas it was only detected in the distal part of the small intestine of a 25-week fetus. The receptor-intrinsic factor-cobalamin complex was eluted into the void-volume position when ileum mucosal extract was assayed for receptor activity by gel filtration after incubation with either fetal gastric extract or human gastric juice. The intrinsic-factor-binding capacity of intestinal mucosal extracts ranged from 2.6 to 30.5 fmol/mg and was correlated with the gestational age of six fetuses. The dissociation constant of the receptor for the intrinsic factor-cobalamin complex was estimated at 0.24-0.36 nM at pH 7.4. In conclusion, intrinsic-factor-receptor activity was detected in the whole intestine in 10-19-week fetuses, whereas it was only present in the distal ileum at the end of fetal development.
Schohn
H
H
INSERM U308 Faculté de Medicine, Université de Nancy I, Vandoeuvre, France.
Guéant
J L
JL
Leheup
B
B
Saunier
M
M
Grignon
G
G
Nicolas
J P
JP
D002850:Chromatography, Gel; D003106:Colon / Q000196:embryology* / Q000378:metabolism; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007413:Intestinal Mucosa / Q000196:embryology* / Q000378:metabolism; D007421:Intestine, Small / Q000196:embryology* / Q000378:metabolism; D007437:Intrinsic Factor / Q000378:metabolism*; D007700:Kinetics; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D018000:Receptors, Peptide
D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; C028199:intrinsic factor receptor; D007437:Intrinsic Factor