Vast and apparently paradoxical continuous rise in plasma renin after removal of gently manipulated submaxillary glands in nephrectomized mice.

Gentle manipulation of the submaxillary glands of previously nephrectomized mice results in a vast increase in plasma renin concentration. The concentration reaches 1 to 7 G.U. renin/ml, which is 1,000-fold higher than normal plasma concentrations. The rise is much less pronounced if the glands are removed after the manipulation, confirming the site of the release. However, an apparent paradox is seen: the renin concentration continues to rise even after removal of submaxillary glands as well as kidneys, indicating that a bound a form of renin is also released. The bound renin can be in the form of exocytosed granules or (and) in the form of "protein", the renin of which is activated with time. In spite of the very high renin concentrations the blood pressure is normal or only moderately increased. This disproportion between plasma renin and blood pressure can be caused by a simultaneous release of submaxillary kallikrein and renin, which have conteracting effects on the blood pressure.