The effect of aldosterone, cortisol and corticosterone upon the sodium and potassium content of sheep's parotid

Sodium depletion in the sheep results in a fall in parotid salivary sodium/potassium concentra-tion ratio (Na/K) from a normal 25 to 40 (Na, 170 to 185 and K, 4 to 6 mEq per L) to as low 0.3 (Na, 40 and K, 133 mEq per L) (1, 2). Earlier work in this laboratory suggested that this recipro-cal alteration in the concentration of salivary so-dium and potassium was due predominantly to the simultaneous operation of 1) a fall in the salivary secretion rate and 2) an increase in the secretion of electrolyte-active adrenal steroids. If suitable al-lowance were made for the effects of variation in the parotid salivary secretion rate and the latency of the response, it was proposed that the salivary Na/K ratio could be used as an index of the re-lease of electrolyte-active steroid into the circula-tion (2-5). Cortisol (6), corticosterone (6), and aldosterone (7-9) have been identified in sheep adrenal ve-nous blood. In order to obtain a basis for evalu-ating the contribution of each of these components of the adrenal secretion to the fall in parotid sali-vary Na/K ratio observed during different physi-ological states, the effects of these steroids upon salivary Na and K were studied in a series of ex-periments in normal and adrenalectomized sheep. METHODS Animals. Eighteen crossbred Merino wethers were used in this study. All had unilateral parotid fistulae (1) and carotid loops, and 11 were bilaterally adrenalec-tomized (5). Of the nonadrenalectomized sheep, tw