The Renin System in Mice

In different strains of mice the sum of renal and submaxillary renin was found to vary from about 10 to about 1000 Haas‐Goldblatt units, about 7 to well over 98 per cent of which was found in the submaxillary glands. The plasma renin and angiotensinogen concentrations were independent of these variations. Following submaxillary sialo‐adenectomy there was only a slight decrease, if any, in plasma renin or increase in plasma angiotensinogen. Contrary to this, nephrectomy was followed by a marked decrease in plasma renin and a marked increase in plasma angiotensinogen, both of which were independent of the highly varying amount of submaxillary renin left in the organism. The postnephrec‐tomy increase in angiotensinogen was further independent of variations in the pre‐operative plasma and renal renin, supporting the previous conclusion that it must be due to loss of some internal factor other than renin or to loss of some external renal function.