Cyclocytidine-induced release of nerve growth factor from mouse submandibular glands enhances regeneration of sympathetic fibers in adult mice.

The injection of a drug endowed with the property of stimulating alpha-adrenergic receptors, cyclocytidine (Cyclo-C), produces drastic depletion of NGF from the granular convoluted tubules (GCT) of the mouse submaxillary salivary gland and a marked NGF level increase in the bloodstream. The NGF discharged from the gland gains access to the blood. Histological studies, immunohistochemistry, in vitro biological assays and radioimmunoassays gave evidence for the growth response elicited by the endogenously released salivary NGF in intact and surgically axotomized sympathetic ganglia. These results suggest that the mouse salivary NGF displays a biological activity on its target sympathetic nerve cells.