Decreased cyclic GMP levels in rat cecum mucosa during adaptive stimulation of Na-K-ATPase.

In rat cecal mucosa, Na-K-ATPase specific activity and sodium and fluid absorption were increased by giving polyethylene glycol administration with the drinking water. Whereas cyclic AMP levels were unchanged, cyclic GMP was reduced by about 50%. This finding suggests a regulatory role of cyclic GMP in intestinal sodium and fluid absorption.