Plasma Renin Activity in Decompensated and Non-Decompensated Diabetes Insipidus. The Following is also a Contribution Toward the Regulation of Renin Secretion

Plasma renin activity was found to be extremely high in two patients with diabetes insipidus: the first case was characterized by consistent hypernatremia (diabetes insipidus hypersalaemicus occultus) due to an ectopic pinealoma, while the second case was associated with a craniopharyngeoma. The increased plasma renin activity in hypernatremic states is remarkable in that diseases associated with hypernatremia are usually accompanied by a decrease of plasma renin activity. In addition to the known stimuli for renin release (baroreceptors, chemoreceptors, neural and humoral stimuli) intracellular volume receptors might be important factors in the regulation of renin secretion. This theory is based on studies of sodium and fluid balance in these two cases of diabetes insipidus. The possible relationship between sodium and fluid balance on the one hand, and plasma renin activity on the other hand, are discussed. (Author)