Mammalian receptors for glucagon-like-peptide-1 (GLP-1), corresponding DNA and recombinant expression systems, and screening assays for GLP-1 agonists and enhancers

An isolated glucagonlike peptide-1 (GLP-1) receptor polypeptide having the amino acid sequence of a naturally occurring mammalian GLP-1 receptor encoded by a cDNA molecule isolated from a pancreatic islet library and comprising a nucleotide sequence selected from the group consisting of:

• SEQ ID NO:
• 1;
• SEQ ID NO:
• 3;
• and
• the sequence of a cDNA molecule capable of specifically hybridizing with a probe having the sequence of the complement of SEQ ID NO:
• 1 or SEQ ID NO:
• 3 under conditions of relaxed stringency, wherein a probe having the sequence of the complement of SEQ ID NO:
• 1 will specifically identify a cDNA comprising the sequence shown in SEQ ID NO:
• 3 in a human cDNA library,
• said receptor polypeptide capable of binding GLP-1 with a K.sub.D of less than 100 nM.