Edwin L. Cohen

Suppression of sympathetic nervous function in low-renin essential hypertension.

Study of general haemodynamics in 15 patients with low-renin essential hypertension showed haemodynamic and pathophysiological heterogeneity. However, there was suppression of sympathetic nervous system function in all low-renin patients, regardless of haemodynamic pattern. Subnormal sympathetic nervous activity was manifested by a low normal mean plasma-noradrenaline concentration at rest, diminished noradrenaline responsiveness to postural stimulation, and a reduced blood-pressure response to the indirectly acting sympathomimetic amine tyramine. It is proposed that the syndrome of low-renin essential hypertension is of diverse aetiology, but with secondary sympathetic nervous system underactivity as a feature common to the various forms. The low plasma-renin activity is probably an expression of defective sympathetic nervous system stimulation of renin release.

Postural Augmentation of Plasma Renin Activity and Aldosterone Excretion in Normal People

Peripheral plasma renin activity and aldosterone excretion rates have been measured in normal people during recumbency, recumbent exercise, tilting, and continuous ambulation. Upright posture induces a prompt elevation in peripheral plasma renin activity beginning in 15 minutes and peaking between 60 and 120 minutes. Aldosterone excretion is increased during 120 minutes of upright posture and correlates directly with the elevation in renin activity. Upright posture induces increased plasma renin activity regardless of the level of sodium intake in the preparatory diet. Concomitant measurements of endogenous creatinine clearance and the rates of excretion of sodium and potassium suggest that a fall in renal arterial perfusion resulting from upright posture induces increased release of renin and the subsequent secondary stimulation of aldosterone secretion. Our data indicate that the changes in plasma renin activity are due to changes in the amount of the enzyme rather than to changes in other elements of the reninangiotensin systm. This report discusses the physiologic importance of postural augmentation of renin production, emphasizing that for proper interpretation of values of plasma renin activity, posture as well as dietary factors must be considered and controlled.

Normal and Altered Function of the Renin-Angiotensin-Aldosterone System in Man: Applications in Clinical and Research Medicine

Excerpt I am pleased to be able to present the 1965 John Phillips Memorial Lecture for several reasons. First, I am happy to be participating in the memorialization of an eminent American physician...

Studies on the partial isolation of human renin

Abstract Studies on the partial isolation of human renin have been described. We have observed that: 1. 1. Thorough disruption of the cell membranes by an all glass homogenizer increases the yield of enzyme eluted from renal tissue. 2. 2. QAE-Sephadex and calcium gel cellulose chromatography are valuable tools for the purification of renin. Gradient elution is superior in ion exchange chromatography of human renin. The properties of the final preparation obtained (Fraction 9) are: mol. wt. 42 000; isoelectric point pH 5.25; A280 mμ:A260 mμ = 2.1; pH optimum for human substrate 5.5; hog substrate 7.5–8.5; and tetradecapeptide renin substrate 5.5. Specific activity 8.4 Goldblatt units per mg protein (by bioassay in the dog). 3. 3. Evidence was obtained for the existence of considerable amounts of angiotensin I converting enzyme in human kidneys. Problems concerning the standardisation of human renin have been discussed.

Renin-secreting juxtaglomerular-cell adenoma. Preoperative clinical and angiographic diagnosis.

A renin-secreting renal cortical tumor was diagnosed by selective magnification angiographic techniques in a young man with severe arterial hypertension, hypokalemia, and overproduction of aldosterone. The plasma renin activity levels in the renal effluent from the tumor side were significantly high, making the diagnosis virtually certain preoperatively. Removal of the tumor, 15 mm in diameter, resulted in complete cure.

A Plasma Inhibitor of the Renin-Antirenin Reaction and the In Vitro Generation of Angiotensin I

In the course of studies designed to develop a radioimmunoassay system for the detection of renin, we have identified in human plasma a potent inhibitor that interferes with the renin-antirenin reaction. Utilizing gel filtration, this renin-antirenin inhibitory activity was found to have the same molecular size as renin substrate. However, it could be separated from renin substrate by ion-exchange chromatography. When fractions containing this activity were tested in an in vitro system containing renin and renin substrate, they were found to inhibit the generation of angiotensin I.

Hypertension, Hypokalemia, Suppressed Plasma Renin Activity and Aldosteronopenia Induced by Ingestion of Licorice.

Excerpt Glycyrrhizic acid is a potent sodium-retaining substance existing in high concentration in licorice extract. Previous reports from this laboratory have documented the great sodium retention...