• Gastrin, any of a group of digestive hormones secreted by the wall of the pyloric end of the stomach of mammals, which occurs in three forms: as a 14-, 17-, and 34-amino-acid polypeptide.
• The exons 2-3 of mouse Gast gene that encode the whole molecule (ATG to STOP codon), including 3’UTR were replaced by human counterparts in B-hGAST mice. The promoter and 5’UTR region of the mouse gene are retained. The human GAST expression is driven by endogenous mouse Gast promoter, while mouse Gast gene transcription and translation will be disrupted. 
• Mouse Gast mRNA was detectable in wild-type C57BL/6N mice. Human GAST mRNA  was detectable in homozygous B-hGAST mice. 
• Application: This product is used for pharmacodynamics and safety evaluation of  drugs.

Gene targeting strategy for B-hGAST mice. The exons 2-3 of mouse Gast gene that encode the whole molecule (ATG to STOP codon), including 3’UTR were replaced by human counterparts in B-hGAST mice. The promoter and 5’UTR region of the mouse gene are retained. The human GAST expression is driven by endogenous mouse Gast promoter, while mouse Gast gene transcription and translation will be disrupted. 

Strain specific analysis of GAST gene expression in wild-type mice and B-hGAST mice by RT-PCR. Stomach RNA was isolated from wild-type C57BL/6N mice (+/+) and homozygous B-hGAST mice (H/H). Mouse Gast mRNA was detectable only in wild-type C57BL/6N mice. Human GAST mRNA was detectable only in homozygous B-hGAST mice but not in wild-type C57BL/6N mice.