When solid chow was reintroduced for 2 days to rats previously maintained on an all-liquid diet, [3H]thymidine incorporation into rat parotid gland was 2.4-4.4 times that of chow-fed or liquid-fed animals. When the submandibular-sublingual glands were removed before the change in diet from liquid to solid food, values for [3H]thymidine incorporation of parotid gland were not statistically different from those of chow-fed rats: the increase was completely prevented. The increase in gland size that accompanied the change in dietary consistency was not prevented by prior submandibular gland ablation; [3H]uridine incorporation was also not different from that of chow controls. The removal of both the sympathetic and parasympathetic nerves to the parotid gland before the dietary manipulation also suppressed [3H]thymidine incorporation into parotid, and values did not differ from chow controls. Moreover, the return to normal gland size (chow level) also was prevented by autonomic denervation. The data show an important role of the submandibular gland in regulation of the thymidine increase associated with the enhanced parotid activity that accompanies the change from liquid to solid diet. However, the submandibular gland does not have an important role in regulation of the increase in gland size that also accompanies the dietary change, whereas the autonomic nerves have an important role in regulation of hypertrophy and hyperplasia of parotid gland.
Protection against autonomic denervation following acute myocardial infarction by preconditioning ischemia.
