Neural and dietary modulation of proline-rich protein and 4 beta-galactosyltransferase biosynthesis in rat parotid glands.

Maintenance of rats on a bulk diet (50 per cent inert cellulose and 50 per cent laboratory chow) before or after the removal of the submandibular-sublingual glands resulted in hypertrophy of the parotid gland, and the induction of basic proline-rich proteins in that gland with apparent molecular weights similar to those found after chronic administration of isoproterenol. Surgical removal of either the sympathetic or parasympathetic nerve, or of both, impeded both gland hypertrophy and the gene expression for proline-rich protein in the denervated gland. Rats fed normal chow did not have induction of these proteins in the innervated control parotid nor in the denervated contralateral gland. The experimental regimen also showed in-vitro translation of mRNA with electrophoretic protein patterns similar to those with isoproterenol treatment. There was also increased synthesis of the enzyme 4 beta-galactosyltransferase (EC 2.4.1.38).