Adrenergic factors influencing the mitotic rate in stratified squamous epithelium of the buccal mucosa of the rat.

1. An in vivo stathmokinetic technique was used to determine the immediate effect of various adrenoceptor agonists and antagonists on the mitotic rate in the stratified squamous epithelium of the rat buccal mucosa. 2. The mitotic rate increased significantly in rats treated with propranolol and with practolol, whereas the mitotic rate decreased significantly in rats treated with metaraminol. In animals treated with isoprenaline and phentolamine the mitotic rate did not differ significantly from the control value. 3. The nature of the involvement of adrenergic mechanisms with cell proliferation is still uncertain but both alpha- and beta-adrenergic mechanisms appear to be associated with the control of cell proliferation.