F. Gross

Changes in renin content in kidneys of renal hypertensive rats.

Summary The renin content of fresh kidney tissue was assayed indirectly by a modification of Schaffenburgs method(3) in rats with experimental renal hypertension, under a variety of conditions. Clamping one renal artery caused an increased concentration of renin in the clamped kidney, and a fall in the contralateral kidney. Clamping both renal arteries also caused an increase in renin content of the more efficiently clamped kidney and a decrease in the contralateral kidney. Renin content in the one remaining kidney was not influenced by unilateral nephrectomy in normal rats. Clamping the one remaining renal artery in unilaterally nephrectomized rats induced hypertension, but did not result in an increase in renin content of the kidney. Similarly, removal of the undamped kidney in rats with hypertension due to a unilateral renal artery clip resulted in a slow decrease of renin content in the clamped kidney to normal values. Removal of the clamped kidney in such animals caused a rapid fall of blood pressure and a subsequent slow increase of renin content in the remaining undamped kidney. A unifying hypothesis to explain these changes is presented, involving a concept of renin inhibition or inactivation.

A new imidazoline derivative with marked adrenolytic properties.

Conclusions The compound 2-[N-p′-tolyl-N-(m′-hydroxyphenyl)-aminomethyl] -imidazoline HCl, (C-7337), is a potent adrenolytic agent but much less active as a symptatholytic drug. It is effective orally. 6

Unique Specificity of Mouse Angiotensinogen to Homologous Renin

Summary Angiotensinogen contained in mouse plasma reacts exclusively with mouse kidney extract containing renin, to release angiotensin. Renin or kidney extracts from other species (pig, rat, hamster, rabbit) as well as from man do not liberate angiotensin if incubated with mouse plasma substrate. Plasma from nephrectomized mice, when incubated with mouse kidney extract, gave about 6 to 7 times higher yields of angioten-sin-like substance. Administration of DCA together with salt loading for a period of 3 weeks reduced renin activity in mouse kidneys, but not as markedly as in rats. The resistance of mouse renin substrate to heter-ologous renin appears unique among non-primates.

Pressor Substances in Kidneys of Renal Hypertensive Rats with and Without Adrenals

Summary 1. In rats, clamping of one renal artery or encapsulation of one kidney leads to a significant decrease in pressor material (renin ?) in the contralateral “untouched” kidney, while in the clamped kidney pressor activity is normal or only slightly enhanced. 2. These changes in content of renal pressor material are not necessarily accompanied by increase in blood pressure but were observed in every case of renal hypertension. 3. When hypertensive rats were adrenalectomized and maintained on small doses of cortisol, there followed a decrease in blood pressure and restoration of level of pressor material in the unclamped kidney. 4. It is suggested that diminution of pressor material in the unclamped kidney is not a prerequisite but a consequence of the pathological situation leading to renal hypertension.

EFFECT OF BLOOD VOLUME CHANGES ON RENIN-LIKE ACTIVITY IN BLOOD.

Summary By means of the isovolemic cross-circulation technique rapid variations in concentration of renin-like activity in blood were demonstrated following marked alterations of the intravascular volume. Bleeding leads within 10 to 15 minutes to a 3- to 4-fold increase in concentration of renin-like substance in the blood, while over-transfusion results in a reduction of this activity within 24 hours. Nephrectomized rats do not react to hemorrhage with an increase in renin-like activity in blood. The renin content of the kidneys showed no detectable changes in bleeding as well as in overtransfusion experiments.

Histochemical Changes in Kidneys and in Salivary Glands of Rats with Experimental Hypertension

Summary In rats with experimental hypertension due either to overdosage with DCA and salt or to unilateral clamping of renal artery, activity of glucose-6-phosphate dehydrogenase (G6PD) was determined histochemically in the macula densa and simultaneously in ducts of submaxillary gland. In both kidneys of animals with DCA hypertension and in unclamped kidney of animals with renal hypertension, G6PD is diminished to a comparable degree, both in macula densa cells and in the duct epithelium of submaxillary gland, whereas activity in the clamped kidney is higher than normal. Simultaneously there is a widening of ducts in the salivary gland comparable to that seen in cortical tubular system in the kidney. Adrenalectomy is followed by increased G6PD activity in the macula densa and a high normal activity in the submaxillary gland.

Tierexperimentelle Untersuchungen ber den Einflu von Steroiden auf die Haut

Reines Δ5-pregnen-3β-ol-20-on (Pregnenolon) und dessen Essigsaure-, Propionsaure- und Myristinsaureester, denen keine geschlechts-spezifische Wirkung zukommt, fuhren in bestimmtem Konzentrations-bereich und in salbenartigen Emulsionen, wiederholt lokal angewandt, an der Meerschweinchenhaut zu einer Anregung des Zellwachstums und zu einer Zellregeneration in der Epidermis mit Vermehrung der Zellen und Erhohung der die Epidermis aufbauenden Zellagen, wie sie in ahnlicher Weise nach gleichartiger Anwendung des geschlechtsspezifischen Oestradiols feststellbar ist.ZusammenfassungReines Δ5-pregnen-3β-ol-20-on (Pregnenolon) und dessen Essigsäure-, Propionsäure- und Myristinsäureester, denen keine geschlechts-spezifische Wirkung zukommt, führen in bestimmtem Konzentrations-bereich und in salbenartigen Emulsionen, wiederholt lokal angewandt, an der Meerschweinchenhaut zu einer Anregung des Zellwachstums und zu einer Zellregeneration in der Epidermis mit Vermehrung der Zellen und Erhöhung der die Epidermis aufbauenden Zellagen, wie sie in ähnlicher Weise nach gleichartiger Anwendung des geschlechtsspezifischen Oestradiols feststellbar ist.