Influence of the microbial flora on the amount of CCK8- and secretin21-27-like immunoreactivity in the intestinal tract of mice.

Determination of CCK8- and secretin21-27-like immunoreactivity in the intestinal tract of germ-free and control mice with the modified-phage assay showed that in germ-free mice as well as in control mice the highest amount of immunoreactivity is present in extracts from the small intestines. CCK8-like immunoreactivity is about 2 times higher and secretin21-27-like immunoreactivity is about 3 times lower in an extract from the small intestines of control mice than in the comparable extract of germ-free mice. The extracts from the small intestines of germ-free and control mice were applied to a Sephadex G-50 column. Higher molecular weight CCK8- and secretin21-27-like immunoreactive material was found to be present in the extract from the small intestines of control mice and virtually absent in the extract from the small intestines of germ-free mice.