The Secretin family is a small family of 15 GPCRs (GPCR-B1) that all have an extracellular hormone-binding domain and bind peptide hormones. The members of this family are the calcitonin and calcitonin-like receptors (CALCR, CALCRL); the corticotropin-releasing hormone receptors (CRHR1, CRHR2); the glucagon receptor (GCGR); the gastric inhibitory polypeptide receptor (GIPR); the glucagon-like peptide receptors (GLP1R, GLP2R); the growth-hormone-releasing hormone receptor (GHRHR); the adenylate cyclase activating polypeptide receptor (PAC1/ADCYAP1R1); the parathyroid hormone receptors (PTHR1, PTHR2); the secretin receptor (SCTR); and the vasoactive intestinal peptide receptors (VIPR1, VIPR2).
The corticotropin releasing hormone receptor (CRF1, or CRHR1) is likely to be involved in mental disorders, and both infection and autoimmune disorders.
 CRHR1 Receptor binding and lipophilicity of pyrrolopyrimidines, potential nonpeptide corticotropin-releasing hormone type 1 receptor antagonists. K.C. Rice et al. Bioorg. Med. Chem. 2002, 10, 175–183.