Adrenalectomized Dogs Research Articles

Electroconvulsive Threshold Elevation: From Daily Stimulation of Adrenalectomized Animals

The elevation of electroconvulsive threshold, which develops in cats during repeated daily measurements threof might result from an increased production of deoxycorticosterone. Bilateral adrenalectomy followed by maintenance on deoxycorticosterone and cortisone in fixed dosages did not prevent subsequent elevation of the threshold in either cats or miniature dogs. The elevation rate in the adrenalectomized dogs exceeded that in the intact control dogs. This elevation, which resembles tolerance, in the intact cat or miniature dogs, is not dependent on an increased production of adrenocortical hormones; it may more likely be the result of cerebral rather than extracerebral adaptation.

Potassium excretion during adrenal insufficiency.

IT was first noticed by Harrison and Darrow1 that in adrenal insufficiency in dogs the renal tubular function of preserving sodium and excreting potassium was disturbed. This was afterwards interpreted generally as the result of insufficiency of the sodium-potassium exchange mechanism, which was advocated by Berliner et al.2 originally for the explanation of the high output of potassium under a special condition of extremely high potassium load. That the abnormality of excretion of potassium in adrenal insufficiency, except in the final stage, was not dependent upon changes in the glomerular filtration rate has been stressed by Harrison and Darrow1. However, their experiments were done under special conditions by giving potassium chloride (10 g) to the intact dog or the adrenalectomized dog treated with cortical extract in order to compare their concentration ratio (urine/plasma ratio) of potassium with that of the untreated adrenalectomized dog at the same high serum potassium-level found in the latter. The ratio obtained in the former reached 40–75, whereas that found in the latter was about 10. In our experiences the former values seem to be abnormally high, perhaps due to adaptation to potassium load2 to which no attention was paid, while the latter lies rather in the normal range. On the other hand, Harrop et al.3 and recently Fukuda and Koyama4 have noticed that the rise of concentration of potassium in the plasma in adrenal insufficiency paralleled that of urea or non-protein nitrogen and suggested the possibility that the disturbance in excretion of potassium might be the result of reduced glomerular nitration rate. Therefore, experiments were performed to find out whether the clearance of potassium shows direct relation to the glomerular filtration rate in adrenal insufficiency in dogs. The results were compared with those obtained from intact dogs and adrenalectomized dogs maintained with cortisone (1 mg/kg per day) when the glomerular filtration rate was changed by altering the intake of sodium chloride (0–2.0 g/kg per day).

Study on mechanism of acid and ammonia excretion by kidney after acid load.

After isotonic hydrochloric acid was infused intravenously into 30 normal, 10 adrenalectomized and 5 DCA administered adrenalectomized dogs, changes of acid-base balance in the blood and urine were observed and the urinary acidification as well as of ammonia secretion was investigated.The results obtained are summarized as follows:1. Urinary output of titratable acidity and ammonia increased after the acid infusion and bore an inverse correlation with the blood pH. Acid urine formation was less remarkable in adrenalectomized dogs, while it was restored after the administration of DCA.2. A positive correlation was found between plasma potassium concentration and urinary titratable acidity. The amount of titratable acidity is, however, lower in adrenalectomized dogs than normal dogs at the same plasma potassium concentration, while it is higher in DCA administered dogs.3. It follows that the mineralcorticoid from the adrenal glands can play an importantant role in acid urine formation, probably by promoting an ion exchange mechanism of H+ for Na+ across the cell membrane of the renal tubule in acidosis. The fact that the acid urine can also be produced even in the adrenalectomized dog, though to a lesser extent, indicates that the urinary acidification can be initiated by the other factor than the mineralcorticoid. The direct effect of acidosis was suggested as the other factor, which may influence the H+ ion secretion mechanism of tubular cell in association with either K+ deficiency or pH decrease in the cells.4. Urinary ammonia bears a clear inverse correlation with urinary pH, and an appreciable depression in urinary output of ammonia appeared in adrenalectomized dog, and this fact can be explained as due to the decrease of Na+-NH4+ exchange in adrenalectomized dog. The predominance of the ion exchange theory over the capture-by-diffusion theory in mammals for the urinary ammonia excretion was discussed.5. About the renal glutaminase and carbonic anhydrase activity, no difference could be found between normal and adrenalectomized dogs, suggesting no difference in the ability of production of acid and ammonia within the renal tubular cell in two kinds of animals.6. It follows that a disturbance of Na+-H+ and Na+-NH4+ ion exchange mechanism in the renal tubule in adrenalectomized dogs would result in a failure of adaptive increase of urinary output of acid and ammonia in acute acidosis.7. It is confirmed with dog experiments that the increase of urinary ammonia in prolonged acidosis is due to an adaptive increase of renal glutaminase.

Effect of cortisone on gastric secretion in adrenalectomized dogs.

THERE HAS BEEN increasing interest in the hormonal aspects of peptic ulcer. Various reports have implicated hormonal substances from the pancreas, 1 gonads, 2 pituitary, 3 and the adrenals. 3 Whether there is any direct relationship between the activity of these glands and peptic ulceration still remains controversial. A brief resume of the literature shows conflicting reports as to the effect of cortisone on gastric secretion in various experimental situations. Plainos and Philippu 6 gave 60 mg. of prednisone daily to pouch dogs with intact adrenals and noticed a 412% increase in hydrochloric acid (HCl) and a 365% increase in pepsin secretion. Zubiran et al. 7 gave dogs with intact adrenals and different types of pouches 100 mg. of cortisone daily and produced a 30% to 209% increase in hydrochloric acid secretion. Wiederanders et al. 8 gave 300 mg. of cortisone to dogs with Heidenhain pouches and intact adrenals and

A DOUBLE ISOTOPE DERIVATIVE METHOD FOR THE DETERMINATION OF ALDOSTERONE IN PERIPHERAL PLASMA

ABSTRACT The details of a method for the determination of aldosterone at the level of 1 ng or more are described. A combination of the isotope derivative principle and the isotope dilution principle, using 35S and 131I labelled piodobenzenesulfonic acid anhydride (pipsan) as the labelled reagents, has been employed. A quantitative or almost quantitative and reproducible esterification of the 21-hydroxyl group of aldosterone and an 80% recovery of the steroid added to plasma can be achieved by the procedure described. The blank value has been determined by the analysis of epripheral plasma of adrenalectomized dogs and was found to be indistinguishable from zero and therefore less than 3 ng per 100 ml of plasma. In salt depleted anaesthetized dogs the aldosterone level was 20–30 ng per 100 ml. The concentration increased considerably during adrenalectomy and decreased with a »half life« of 20–30 minutes from the time this was completed.

Sympatho-adrenal responses during general anaesthesia in the dog and man.

Plasma catecholamine levels were studied during general anaesthesia with diethyl ether, cyclopropane, and halothane in dogs and human subjects. Anaesthesia with ether/oxygen caused highly significant increases in plasma noradrenaline in dogs and man. The response was less marked in man, but a significant direct correlation could be established (in a small number of patients) between the rise in plasma noradrenaline and blood ether concentrations during ether anaesthesia without surgical interference. Plasma adrenaline was also significantly increased in dogs during ether anaesthesia, and in man to a lesser extent; highly significant rises were measured during surgery in man. The severe metabolic acidosis induced by diethyl ether in the dog bore a direct relationship to circulating catecholamine concentration and was greatly reduced by bilateral adrenalectomy. A mild but definite metabolic acidosis was measured during nitrous oxide/ oxygen/ether and ether/oxygen anaesthesia in man. In adrenalectomized dogs, variable moderate rises in plasma noradrenaline were measured during ether anaesthesia, from which it is inferred that in this species the rise in plasma noradrenaline stems partly from extra-adrenal areas. Since hypercarbia superimposed on ether anaesthesia in adrenalectomized dogs caused further increases in plasma noradrenaline, it is considered that the extra-adrenal sympathetic excitation induced by ether is submaximal.

THE ACUTE EFFECTS OF INFUSED ADRENAL STEROIDS ON RENAL FUNCTION IN ADRENALECTOMIZED DOGS

ABSTRACT Infusions of cortisol (11β,17,21-trihydroxy-pregn-4-ene-3,20-dione), prednisolone (11β,17,21-trihydroxy-pregna-1,4-diene-3,20-dione), aldosterone (11β,21-dihydroxy-3,20-dione-pregn-4-en-18-al), and adrenal cortical extract have been given to four adrenalectomized dogs. The changes of inulin, creatinine, para-aminohippuric acid clearances, urine volume, and sodium and potassium excretion have been measured. Between experiments oral replacement therapy was given to obviate the effect of slow absorption of previously injected steroids. The effects of steroid-free control infusions have been studied. Varying the rate of infusion from 1.0–2.6 ml/min, and sodium from 0–170 μeq/min has little effect on glomerular filtration rates (G. F. R.). Infusions of cortisol (1.5 and 10 mg/h), prednisolone (2 mg/h) and adrenal cortical extract (10 ml/h) raised the G. F. R. and lowered the filtration fraction. As the G. F. R. increased the ratio creatinine: inulin clearance fell. The different dogs varied in their responses. Infusions of prednisolone and cortisol (1.5 mg/h) usually increased sodium output as G. F. R. rose. With aldosterone, adrenal cortical extract and cortisol (10 mg/h) there was sodium retention in three of the four dogs, the fourth was resistant to the sodium retaining action of these steroids while the plasma level was high. All steroid infusions increased potassium excretion. Cortisol increased free water clearance independent of G. F. R. provided the infusion rate exceeded 2 ml/min, prednisolone increased both osmolar and free water clearance, aldosterone increased osmolar clearance and reduced free water clearance.

Renal excretion of protein in adrena-lectomized dogs treated with various adrenal cortical hormones.

The excretion of urinary protein was studied in four adrenalectomized dogs given different types and levels of adrenal cortical hormone replacement. Distinctive changes in the levels of serum proteins as well as changes in serum electrolytes were associated with only minor alterations in the rate of urine protein excretion. An increase in the clearance of globulins during the period of high cortisone dosage was noted. This was due to diminished serum concentrations of this fraction while the excretion rate remained constant. These data suggest that the adrenal cortical hormones play a minor role in the regulation renal protein excretion by the normal dog.

Study of the mechanism of hyperglycemia and arterial hypertension produced by venom of the scorpion, in the dog

In the present paper we studied the mechanism of the hyperglycemia and hypertension evoked by the intravenous injection of scorpion venom (Tityus bahiensis) in the dog. We used 34 dogs, of both sex, weighing between 4.3 to 22 kg. These animals were divided in 3 groups and the following experiments were performed: in the first group (8 dogs) the animals were adrenalectomized after the intravenous injection of chlorpromazine; in the second group (16 dogs) the animals were injected with ganglionic blocking drugs (9.295 Ciba and hexamethonium); in the third group (10 dogs) the naimals were injected with dibenamine, and in 3 of them the adrenal glands were removed. The dogs of each group were injected intravenously with aqueous extract of 2 telsons of scorpion/kg; the average weight of each telson was 6,5 mg. The following results were obtained: 1) The hyperglycemia evoked by scorpion venom, in adrenalectomized dogs, was inhibited by chlorpromazine; 2) Ganglionic blocking drugs (9.295 Ciba and hexamthonium) were inefective as far as the hyperglycemic and pressor effects of venom are concerned; 3) In the animals treated with dibenamine, the venom produced a fall in blood pressure, both in the controle and in the adrenalectomized. The present experiments suggest that the scorpion venom has, besides the central action already described by other investigators, an adrenergic action, very similar to the adrenaline. On basis of our experiments we think that the adrenergic action is responsible, in part, by the productrion of hyperglycemia and hypertension.

Role of catecholamine release in morphine hyperglycemia.

The mechanism of morphine hyperglycemia was studied in intact and chronically adrenalectomized dogs. Adrenergic blocking agents were used to provide a further analysis of the hyperglycemic action of morphine. Venous hematocrit and plasma specific gravity were measured on the assumption that catecholamines released by morphine could elicit a contraction of the spleen. Morphine administration caused a rise in both sugar and hematocrit; after adrenalectomy, blood sugar and hematocrit showed a much smaller increase. Morphine hyperglycemia was antagonized by dihydroergotamine and dichloroisoproterenol but not by Dibenamine. Since this is the pattern of epinephrine hyperglycemia it was concluded that morphine hyperglycemia is mediated by the release of catecholamines, mainly from the adrenal medulla. Atropine and Artane failed to counteract morphine hyperglycemia. Thus these experiments, as far as the blood sugar is concerned, do not favor the hypothesis that morphine acts through an anticholinesterase mechanism.

Clinical use of a new diagnostic agent, methopyrapone (SU-4885), in pituitary and adrenocortical disorders.

Excerpt Disorders involving the adrenocortical secretion of cortisol have become more precisely characterized within recent years as knowledge concerning pituitary-adrenal physiology has increased ...

Effect of strophanthidin on the renal tubules of dogs.

The nature and mechanism of the diuresis produced in the dog by strophanthidin was investigated by infusion of the drug into one renal artery. Saline-loaded dogs respond to strophanthidin infusion with a prompt fall in glomerular filtration rate (GFR) and a delayed saluresis and diuresis. The effect on electrolyte transport can be blocked by loading with potassium salts but the fall in GFR can be only partially prevented. Strophanthidin given to adrenalectomized dogs produces the same effect as in the intact animal. The ability to maintain a steep transtubular hydrogen ion concentration gradient is severely impaired. The data are best interpreted as inhibition of the potassium arm of a linked Na-K exchange across the peritubular cell membrane, with diuresis occurring secondary to this block. Impairment of the ability to maintain a steep hydrogen ion concentration gradient indicates an additional effect on linked exchange occurring at the luminal surface of the cell.

NOREPINEPHRINE RELEASE DURING RESPIRATORY ACIDOSIS IN ADRENALECTOMIZED DOGS

NOREPINEPHRINE RELEASE DURING RESPIRATORY ACIDOSIS IN ADRENALECTOMIZED DOGS

Liver phosphorylase in normal and adrenalectomized dogs treated with serotonin.

The hyperglycemic action of serotonin was investigated in 6 normal and 10 adrenalectomized dogs. In normal dogs, intravenous injections of serotonin were followed promptly by hyperglycemia, decreased liver glycogen and increased liver phosphorylase activity. In control adrenalectomized dogs treated with saline, a progressive decrease in blood glucose and liver glycogen was observed. Serotonin injections did not prevent these phenomena and caused only a delayed increase in phosphorylase activity. These results are consistent with the hypothesis that the increase of liver phosphorylase activity, glycogenolysis, and blood glucose concentration observed in normal dogs, are not due to a direct stimulation of liver phosphorylase by serotonin, but are secondary to a release of epinephrine from the adrenal glands.

Abrupt changes of water and sodium excretion in normal and adrenalectomized dogs

An experiment was designed to induce rapid changes in sodium and water excretion. With this procedure normal dogs showed a prompt and marked water diuresis, with an accompanying antinatriuresis. The same dogs, adrenalectomized and maintained on constant adrenal cortical hormone therapy, demonstrated an identical response despite the constancy of steroid concentration, suggesting a ‘permissive’ action of the hormones. When the animals were deprived of therapy for several days the excretion patterns of sodium and water did become markedly abnormal. Acute replacement with hydrocortisone restored the water excretion pattern to normal but did not correct the abnormal sodium excretion pattern. Aldosterone, given prior to and during the experiment, failed to restore either the water or sodium excretion patterns. The results obtained with acute replacement of hydrocortisone and aldosterone were identical with those obtained with hydrocortisone alone.

Effect of mineralo- and glucoccoticoids on fasted adrenalectomized dogs subjected to electroshock.

SummaryElectroshock induces circulatory failure in fasted adrenalectomized dogs maintained on mineralocorticoid. Treatment with desoxycorticosterone is ineffective and animals succumb exhibiting retention of Na, C1 and renal elimination of but small amounts of K. Despite continued fasting, glucocorticoid injections bring about rapid return of normal activity and vigor accompanied by increased arterial pressure, plasma volume, and decreases in hemoconcentration. Plasma Na and C1 concentrations showed little or no changes but the total quantity of these ions in the intravascular compartment increased significantly. The data indicate that C11 oxysteroids mobilize large amounts of water and electrolyte from extravascular sources of the adrenalectomized dog prostrate from insufficiency and shift them into the intravascular compartment thereby bringing about dramatic and rapid recovery. Thus glucocorticoids, in contrast to mineralocorticoids, are apparently a vital part of the mechanism which maintains the inte...

Circulating epinephrine and norepinephrine in coronary occlusion ∗

1. 1. Following experimental coronary occlusion in thirty-nine dogs, mean values of norepinephrine increased maximally from 1.6 to 10.5 μg-/L. of plasma in thirty-three surviving animals. Serum transaminase increments paralleled norepinephrine elevations in most instances. No changes occurred in circulating levels of epinephrine. Recordings of fluorescence emission spectrums aided in the identification and quantitation of the catecholamines. 2. 2. Essentially the same results occurred in four chronically adrenalectomized dogs. 3. 3. Following coronary occlusion and the administration of a sympatholytic agent (tri-methyl-2-2,6 xylyloxy-propyl ammonium chloride monohydrate), elevated circulating levels of norepinephrine declined progressively to pre-occlusion figures. 4. 4. Of eighteen dogs treated with reserpine, eleven survived the occlusive procedure and showed increments in norepinephrine and transaminase similar to those of the untreated animals, 5. 5. The catecholamine content of the infarct and the adjacent area was not elevated above the values found in normal tissue.

Stop flow analysis of aldosterone and steroidal antagonist SC-8109 on renal tubular sodium transport kinetics.

SummaryIn normal dogs the distal tubule can lower Na concentration almost to zero during stop flow, the minimal concentration achieved being independent of plasma Na concentration. In adrenalectomized animals, minimal distal concentrations achieved are not as low. As plasma Na is increased, minimal distal Na concentration also increases in direct proportion, indicating that adrenalectomy reduces maximal Na concentration gradient which can be maintained across distal tubular cells. Results in adrenalectomized and in SC-8109 treated dogs are identical. Administration of cortisone to adrenalectomized dogs does not repair this defect, but aldosterone restores ability of the distal tubule to lower Na concentration, even in presence of elevated plasma Na. Aldosterone when given to adrenalectomized dogs did not alter proximal Na reabsorption, as this can be estimated by stop flow data.

EXPERIMENTAL INVESTIGATION ON CHINCHOPHEN GASTRIC ULCER

Cinchophen was administered to dogs either orally or intravenously in a dose of 0.15 g/kg for about 3 weeks, and the development of typical gastric ulcer was observed in all the cases. At the same time, activation was demonstrated in neural secretion of the hypothalamus and in function of the adrenal cortex. In total pouch dogs, the secretion of gastric juice began about 3 hours after the oral administration of cinchophen, and lasted about 3 hours. In this case, the secretion of hydrochloric acid, especially pepsin, was remarkably accelerated, and different secretion curve from those of insulin and histamine was obtained.When the pituitary stalk was completely cut, the flow of neural secretion after cinchophen administration was checked at the section of the nerve bundles, and neither adrenocortical function, nor gastric juice secretion was activated, and the development of gastric ulcer was completely inhibited. In dogs whose vagus and sympathetic nerve were blocked, adrenocortical hyperfunction took place after cinchophen administration samely as in normal dogs. Also characteristic enhanced secretion of gastric juice and development of typical gastric ulcer were observed.In bilateral adrenalectomized dogs, gastric juice was not eahanced by cinchophen administration, but typical gastric ulcer developed. This latter was also observed either in bilateral testectomy or bilateral thyroidectomy, both combined with adrenalectomy.

The role of the sympathetic nervous system in the metabolism of free fatty acids

Norepinephrine and epinephrine increased circulating levels of free fatty acids in humans and dogs. The increase was sustained in dogs during infusion of norepinephrine, but transient during epinephrine infusion, which also increased plasma sugar concentration. Anxiety or discomfort in humans and decrease in depth of pentobarbital anesthesia in dogs were accompanied by increased free fatty acid concentration, whereas ganglionic blockade with hexamethonium in dogs resulted in a prompt and sustained fall. In intact and adrenalectomized dogs receiving constant infusions of palmitic acid-1-C14, the decrease in free fatty acid concentration following hexamethonium was shown to result from a reduction in the rate at which they were added to plasma. Only a slight additional reduction was produced by insulin. The effects of norepinephrine and epinephrine on free fatty acid concentration were readily demonstrated during ganglionic blockade, whereas peripheral adrenergic blockade with dibenamine inhibited the response to these amines. The response of free fatty acids to sympathetic amines was also diminished in adrenalectomized dogs maintained with desoxycorticosterone alone. The concept is proposed that the sympathetic nervous system exerts a tonic action on the mobilization of fatty acids from adipose tissuc which may be altered by central stimuli as well as by hormonal factors.