The influence of plasma catecholamines on methotrexate-enhanced rat salivary gland protein secretion.

The acetylcholine-elicited secretory output of parotid protein and amylase, and of submandibular protein from rats receiving 15 mg methotrexate (MTX)/kg for 3 days were 3-6 times greater than that from control animals. Plasma epinephrine and norepinephrine levels in MTX-treated animals were 4-14 times greater than control values. Adrenalectomy reduced the plasma-catecholamine levels, and the acetylcholine-stimulated salivary protein and amylase output. Thus MTX-enhanced salivary protein secretion evoked by acetylcholine stimulation may be mediated, at least in part, by elevated levels of circulating catecholamines.