CHARACTERIZATION OF THE SYNTHESIS AND SECRETION OF TRANSFORMING GROWTH-FACTOR-ALPHA FROM SALIVARY-GLANDS AND SALIVA

Whole saliva collected from rat, mouse, and human sources was found to contain high concentrations of transforming growth factor-alpha (TGF alpha) when analyzed by RIA. The concentrations of TGF alpha in unstim ulated human saliva (age, 30-45 yr; n = 10; 1.5 +/- 3.1 nM) was reduce d with age (age, 55-70 yr; n = 10; 0.4 +/- 0.1 nM), but increased in o ral pathologies manifested in xerostomia (age, 57-70; n = 6; 0.8 +/- 0 .2 nM) and Paget's disease (age, 58-76; n = 8; 2.0 +/- 0.6 nM). Immuno histochemical localization of TGF alpha in the salivary glands of rats and mice revealed specific immunostaining of the granular ductal cell s of the parotid and submandibular glands. Reverse transcription follo wed by polymerase chain reaction amplification of total RNA from the p arotid and submandibular glands of rats and mice demonstrated the pres ence of TGF alpha mRNA, suggesting endogenous synthesis by the salivar y glands. Thus, salivary glands appear to be an exocrine source for a second member of the epidermal growth factor-like growth factor family in the oral cavity.