Abstract
Recent studies (1, 2) of salivary gland function have demonstrated that the rat parotid gland, like the parotids of man and dog (3, 4), produces saliva hypotonic to plasma. Micropuncture and microanalytical techniques have been used to demonstrate that salivary hypotonicity is produced in the striated ducts of the gland by reabsorption of sodium in excess of water from a plasma-like primary secretion (2). The cellular structure of the striated ducts is similar to the structure of the distal tubules of the kidney (5). Since previous studies have indicated that the major action of aldosterone is on the distal tubules of the mammalian nephron (6), we undertook the present study of the role of aldosterone on the function of the rat parotid gland. The effects of this hormone on the handling of sodium and potassium by the parotid in general and the striated ducts in particular were investigated before and after adrenalectomy. The ability of exogenous aldosterone to reestablish normal handling of sodium and potassium by the rat parotid in the adrenalectomized state was investigated.
Methods and Materials. Male, albino rats of the F.W. 49 and Sprague-Dawley strains, weighing 150–200 g, were used in these experiments. The animals were fasted for 24 hr prior to the experiments but were allowed free access to water. They were anesthetized with either Inactin (sodium 5-ethyl-5-methyl-propyl-2-thiobarbiturate) or sodium pentobarbital in doses of approximately 8.0 mg/100 g of body weight. The methods of surgical preparation of the animals, cannulation of the main ducts, and micropuncture of the intercalated and lobular ducts have been described in previous publications (1, 2).
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