Effect Of Nephrectomy Research Articles

Effect of nephrectomy and a low sodium diet on the increase in plasma renin levels produced by hemorrhage.

SummaryIn pentobarbital-anesthetized normal dogs previously fed a diet providing approximately 40 mEq of sodium per day, hemorrhage caused an increase in circulating renin levels. The values continued to rise 30 and 60 min after hemorrhage when blood pressure was returning toward normal. Plasma renin levels were very low 4 hours after bilateral nephrectomy and they failed to rise following hemorrhage in the nephrectomized dogs. Dogs fed a low sodium diet for 14 days had higher prehemorrhage renin values and a much greater increase in plasma renin following hemorrhage than the animals fed 40 mEq of sodium per day.

Mechanisms of hemodynamic control of secretion of aldosterone in the dog

Changes in aldosterone and cortisol secretions were measured in response to constriction of the thoracic inferior vena cava and of the carotid arteries in intact and nephrectomized dogs. Aldosterone and cortisol secretions increased and decreased normally in response to caval constriction and release in nephrectomized animals. Carotid constriction in intact animals increased aldosterone secretion to the same extent as caval constriction, but without increasing cortisol secretion. Cortisol secretion rose after carotid constriction in vagotomized dogs. Nephrectomy led to transient low rates of aldosterone secretion in otherwise intact animals and prevented the increase of aldosterone secretion following carotid constriction in most, but not all, animals in which there was no evidence for ACTH release. Since carotid constriction decreases renin secretion, this effect of nephrectomy is probably independent of the renin-angiotensin system. The data suggest the presence of a mechanism involving the central nervous system, not mediated through ACTH release or the renin-angiotensin system, which is important in the physiologic control of aldosterone secretion, and which may involve an inhibitor of aldosterone secretion.

ANGIOTENSIN, ELECTROLYTES AND ALDOSTERONE.

SummaryThe first part of this paper is concerned with some aspects of renal and endocrine effects on blood pressure and the moderation of these processes by the state of sodium balance. The effects of renin and angiotensin on aldosterone secretion and mechanisms involved in the appetite for salt are considered. The proposition is advanced that any role of aldosterone in the hypertensive process is likely to be understood only when the normal mechanism of control of aldosterone secretion is determined. It has been established by experiments on the transplanted adrenal of the sheep that ionic changes in arterial blood (decrease of sodium and increase of potassium concentration) act directly on the adrenal to stimulate aldosterone secretion, and that this is one pathway of physiological stimulation. This finding has been confirmed by experiments on the dog. The direct ionic effect on the adrenal is, however, probably not the major pathway of stimulation of aldosterone secretion. At present, a central unresolved question in this field of physiology is whether the renin angiotensin system is the normal pathway of stimulation of aldosterone secretion in sodium deficiency, or whether it is a mechanism which operates only in pathological states with renal damage such as malignant hypertension. Evidence such as the correlation between the histology of the juxtaglomerular region of the kidney and sodium balance is suggestive that renin has a physiological role. Consideration of the evidence derived from acute experiments on the effect of nephrectomy on aldosterone secretion indicates the necessity of further investigation on conscious animals under conditions which are as near normal as feasible

Effect of nephrectomy on citrate metabolism in the rat.

The transient rise in plasma citrate which occurs after nephrectomy was studied in rats by measuring plasma citrate concentrations and the rate of conversion of intravenously administered C14-labeled citrate to respiratory CO2. Two hours after nephrectomy plasma citrate was greatly elevated and the rate of oxidation of radioactive citrate was slow. Twenty-four hours after nephrectomy both plasma citrate and rate of oxidation of labeled citrate were normal. In a parathyroidectomized rat in which little rise in plasma citrate followed nephrectomy the rate of conversion of radioactive citrate to CO2 was almost normal. Injection of a large intraperitoneal dose of citrate before administering C14-labeled citrate resulted in a delayed recovery of respiratory C14O2. These results indicate that no decrease in the rate of oxidation of plasma citrate occurs after nephrectomy and that nonrenal tissues are able to metabolize circulating citrate at a substantial rate. Consequently the rise in plasma citrate after nephrectomy probably is due to a temporary increase in the rate of production of plasma citrate rather than to a decrease in the rate of citrate oxidation.

Effect of nephrectomy and splanchnicectomy on plasma disappearance of labeled insulin in the rabbit.

SummaryThe plasma clearance and consumption of I131 labeled insulin was determined in normal, nephrectomized and splanchnicectomized rabbits. The rate constant for plasma disappearance of labeled material was decreased by nephrectomy but not by splanchnicectomy. The plasma clearance of insulin was decreased by splanchnicectomy but the remaining renal circulation was able to maintain the consumption rate of insulin at a normal level.

Effect of nephrectomy on the minute renal circulation.

By means of a technique determining the number of glomeruli patent to plasma flow in a 10-second interval it was established that unilateral nephrectomy was followed by a rise in glomerular count both immediately and 4–7 days after nephrectomy in the 50–125-gm animal. The glomerular count was greater in the 4–7-day postnephrectomy group. The 126–200-gm animals had no immediate response to nephrectomy but showed a rise in count in the 4–7-day postnephrectomy period. It is therefore inferred that under the stated experimental conditions in the normal animal all the glomeruli are not patent to the flow of plasma at any one time.

Studies on "essential" hypertension. V. An endocrine hypertensive syndrome.

Excerpt There is no evidence that so-called "essential" hypertension is a single disease. In fact, the varied clinical picture strongly suggests that it is merely a syndrome caused by several patho...

The effect of nephrectomy on the blood pressure response to renin and angiotonin: Rodbard, S.: Am. J. Physiol. 135: 124, 1941

The effect of nephrectomy on the blood pressure response to renin and angiotonin: Rodbard, S.: Am. J. Physiol. 135: 124, 1941

Studies on “essential” hypertension. III. The effect of nephrectomy upon hypertension associated with organic renal disease: Schroeder, Henry A., and Fish, George W.: Am. J. Med. Sc. 199: 601, 1940

1.1. A portable electromagnetic ballistocardiograph was used to study three groups of individuals: normal persons, patients confined to a hospital and convalescing from noncardiac disease, and patients with obvious cardiac disease.2.2. The records were analyzed by four methods: (a) presence of so-called early M or late M pattern, (b) JK:IJ ratio, (c) H-K time interval and its variation, (d) Brown, Hoffman, and de Lalla criteria.3.3. Precise determination of the limits of the early and late M patterns could not be made.4.4. Observations that the JK:IJ ratio is materially increased by use of the electromagnetic machine are confirmed.5.5. The JK:IJ ratio and the H-K interval and its variation failed to distinguish the three groups. Within the cardiac group those with hypertensive and luetic heart disease had a higher JK:IJ ratio, but some of these individuals had normal ratios.6.6. Records with some degree of variation (1, 2, 3, or 4) were found in 66 per cent of the individuals with frank cardiac disease, in 55 per cent of the patients convalescing from noncardiac disease, and in 14 per cent of the normal persons. Grade 4 ballistocardiograms were found in 31 per cent, 18 per cent, and 0.9 per cent of these three groups, respectively. These results emphasize that abnormality of the ballistocardiogram was not necessarily associated with cardiac disease.7.7. It is emphasized that 34 per cent of the individuals with frank heart disease had normal ballistocardiograms.

Effect of Nephrectomy on Duration of Action of Barbitals

Fitch and Tatum have divided the barbitals into 2 groups based upon the duration of their action and upon the manner in which they cause death. They found that the longer acting barbitals (especially phenobarbital and barbital, ethyl-n-butyl barbital (neonal), isoamyl barbital (amytal), ethyl iso-propyl barbital (barbituric acid of ipral), and also iso-propyl bromallyl barbital (noctal) cause death from pulmonary oedema, while the other barbitals, which they group as the short acting barbitals, when injected intraperitoneally in toxic doses cause death from depression. Our finding that there is a marked difference in action of magnesium sulphate when administered to normal and to nephrectomized rabbits and to nephritic patients, , led us to try this method of testing barbital action. Nephrectomy in etherized rabbits was done through a lumbar incision and was greatly accelerated by the use of a specially devised kidney fork. This was made from an ordinary table fork the first and third tynes of which were sawed off completely, the second and fourth being sharpened and bent around to form a semicircle of 3 cm. diameter. This was inserted through the lumbar incision so as to grasp the kidney, the renal pedicle passing through the space left by removal of the third tyne of the fork. A plate of spring phosphor bronze 7 cm. long and 2 cm. wide, sliding on a collar surrounding the handle of the fork was then pressed down so as to grasp the kidney completely, the kidney was drawn up through the incision and the renal pedical ligated. The incision was then sutured. The operation requires 15 to 20 minutes. The animals were allowed to recover completely from the ether anesthetic and the barbital was injected subcutaneously on the following day.

The Effect of Nephrectomy and Suprarenalectomy in the Rat on Resistance.

There is abundant evidence that the suprarenal gland, in some manner still unknown, plays an important role in the defensive mechanism of the body against poisons. Lewis1, 2, 3 in 1921, established the fact that suprarenalectomized rats are killed by much smaller doses of a variety of poisons than are normal animals. These experiments have been confirmed by Scott,4, 5 Marine and his co-workers,6, 7 Belding and Wyman,8 and more recently Jaffe.9 Stewart and Rogoff,10 and Rogoff and his coworkers,11, 12 while clearly showing in their experiments that suprarenalectomized animals have lowered resistance, believe that this is not specifically due to loss of suprarenal substance. They10, 11 argue as follows: Since the general mortality following double suprarenalectomy in rats obtained by various workers, is about 50 per cent. and since approximately 90 per cent of this mortality occurs between the 5th and 15th day following the operation, therefore any increased sensitiveness found between the 5th and 15th day ...

The effect of nephrectomy upon the toxicity of magnesium sulphate when given by mouth. -- A demonstration

Three rabbits were shown, one normal and two nephrectomized. The nephrectomy was performed nine hours before the demonstration. One nephrectomized animal received by mouth, soon after the nephrectomy, magnesium sulphate (6 grams per kilo in a 25 per cent, solution). The normal animal received by mouth 7 grams per kilo of the same salt. The other nephrectomized rabbit received no magnesium sulphate. At the time of the demonstration the nephrectomized rabbit which had received the salts was under profound anesthesia with complete muscular relaxation, while the other two animals were in an apparently normal state. This shows that in nephrectomized rabbits magnesium salts produce a profound general effect even when given by mouth, and that the absence of such an effect in the usual administration of the salts is due to the comparatively prompt elimination through the kidneys of a large part of the absorbed salts, thus preventing at any given time the accumulation within the organism of a quantity equal to a toxic dose.