Molecular properties of the nerve growth factor secreted in mouse saliva.

Abstract
Some molecular properties of the nerve growth factor (NGF) secreted in mouse saliva and that present in submandibular glands were measured for comparison with previously studied forms of NGF. Mouse saliva contains 2 biologically active NGF species. One has a MW near 114,000, and the other, a MW of 13,000. The larger form is being continuously degraded to yield the smaller one, probably as a result of a slow enzymatic process. Virtually identical results were obtained with crude submandibular gland extracts. The larger NGF is neither the well-known 7S NGF nor 2.5S NGF. The larger salivary NGF is the naturally occurring form of NGF as it exists in the submandibular gland and as it is secreted in saliva. Its biological properties and its function in saliva, if any, remain to be elucidated.