THE GUANYLIN STA RECEPTOR IS EXPRESSED IN CRYPTS AND APICAL EPITHELIUM THROUGHOUT THE MOUSE INTESTINE/

Guanylyl cyclase C (GC-C), a transmembrane receptor for E. coil heat-s table enterotoxin (STa) and for the endogenous peptides guanylin and u roguanylin, catalyzes formation of cGMP and influences fluid and elect rolyte flux in the gut. We characterized the expression of GC-C in the mouse by Northern blot, in situ hybridization, and ligand binding stu dies. GC-C mRNA was present in mouse intestine by embryonic day 12, an d was expressed at high levels in both crypts and villus or surface ep ithelium of adult small intestine and colon, respectively. Radiolabele d STa binding to membranes from several tissues correlated with the pr esence of GC-C mRNA. Extraintestinal GC-C expression was detected only in neonatal mouse liver. The presence of GC-C in mouse intestinal cry pts supports the putative role of GC-C in fluid and electrolyte homeos tasis and resembles the pattern in human tissues. (C) 1996 Academic Pr ess, Inc.