Normal rats or rats parasympathetically denervated on one side by cutting the auriculo-temporal nerve were maintained on a liquid diet for 1 week. After fasting overnight, experimental rats were then offered hard, pelleted food over a period of 2 h, while unfed animals served as controls. The reflex-induced increase in the [3H]leucine incorporation into trichloroacetic acid-insoluble material of the parotid glands following intake of the food in the presence of the muscarinic blocker atropine and α- and β-adrenoceptor antagonists was greater (104 %) than in the absence of the blockers (75 %) in normal rats. The picture was the same when the innervated glands of rats subjected to unilateral parasympathetic denervation were examined. In this case, the protein synthesis increased by 108 % in the presence of the blockers and by 63 % in their absence. Analysis of the parasympathetically denervated and contralateral innervated glands revealed no support for a cholinergic or adrenergic contribution to this response. The increase in protein synthesis in the innervated glands was 86 % in the rats treated with atropine, whilst it was 76 % in those treated with α- and β-adrenoceptor antagonists. The protein synthesis in the denervated glands increased by 57 % in the absence of receptor blockade. Neither atropine (51 %), nor a- and b-adrenoceptor antagonists (52 %), nor a combination of the three blockers (55 %) affected the response of the denervated glands. A large part of the response in the presence of the traditional autonomic receptor blockers was thus dependent on the parasympathetic auriculo-temporal nerve. Under natural feeding conditions, the parasympathetic non-adrenergic, non-cholinergic (NANC) mechanisms are likely to contribute to the synthesis of secretory proteins. Experimental Physiology (2001) 86.5, 605-610.