Xenopsin immunoreactivity in antral G-cells may reside in the N-terminus of gastrin 17.
The nature of xenopsin immunoreactivity in mammalian antral G-cells has been reassessed. Xenopsin immunostaining was most intense in human antral G-cells, present in those of the dog and pig and not detected in guinea pig or rat tissues. Rigorous specificity controls for ionic binding of immunoglobulins to antral G-cell granules indicated that this mechanism was not responsible for xenopsin immunostaining. Preincubation of the xenopsin antiserum with xenopsin, human gastrin 1-13 and gastrin 2-17 completely abolished immunostaining at similar molar concentrations. Gastrin 34 was ineffective at much higher concentrations. These results infer that xenopsin-immunoreactivity in antral G-cells resides in the N-terminal region of gastrin 17. Examination of the primary structures of xenopsin and the N-terminal regions of some mammalian gastrins reveals a hitherto unrecognized homology.
Johnston
C F
CF
Department of Medicine, Queen's University of Belfast, Northern Ireland.
Shaw
C
C
Ardill
J E
JE
Sloan
J M
JM
Buchanan
K D
KD
D000595:Amino Acid Sequence; D000818:Animals; D004285:Dogs; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism*; D006168:Guinea Pigs; D006728:Hormones / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D010455:Peptides; D051381:Rats; D013552:Swine; D029867:Xenopus Proteins
D005755:Gastrins; D006728:Hormones; D009842:Oligopeptides; D010455:Peptides; D029867:Xenopus Proteins; C016832:xenopsin; C013550:gastrin 17