PROTEIN CATABOLISM FOLLOWING TRAUMA IN THE RAT. During the war years extensive observations have been made on patients suffering

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1 THE ROLE OF THE ADRENAL GLANDS IN PROTEIN CATABOLISM FOLLOWING TRAUMA IN THE RAT By R. L. NOBLE and C. GWENDOLINE TOBY From the Research Institute of Endocrinology, McGill University, Montreal, Canada (Received 7 December 197) During the war years extensive observations have been made on patients suffering from various forms of trauma. The changes in protein metabolism have received special interest since Cuthbertson [190, 196] emphasized the marked negative nitrogen balance that regularly occurs after severe trauma. The numerous clinical papers on this subject have recently been reviewed by Howard [195]. Since the original experimental observations of Long, Katzin & Fry [190] showing that the cortex of the adrenal gland was intimately concerned with the conversion of protein to carbohydrate, considerable evidence has been put forward to show that this mechanism may be involved in the metabolic changes taking place after various traumatic procedures. Albright [19], in a consideration of Cushing's syndrome, discussed the possible elaboration of sugar-forming and protein-fixing hormones by the adrenal glands. An increased secretion of the former, resulting in gluconeogenesis from protein, might be responsible for the increased nitrogen excretion occurring after various types of damaging stimuli. This increased production of glucose was sug gested as a protective type of reaction. Other workers have considered the role of the adrenal cortex in defence mechanisms. Thus the hypertrophy of the adrenal glands and evidence of hypersécrétion observed in response to injury has formed the basis of the alarm reaction and adaptation syndrome extensively studied by Selye [196] and his associates. The breakdown of lymphoid structures and the lysis of lymphocytes as a protective response has been shown by White & Dougherty [196] to be related to the liberation of adrenal cortical hormones. Changes in the ascorbic-acid content of the adrenal glands have been found to occur rapidly after various forms of stimuli and have been regarded as indicating increased adrenal function [Sayers, Sayers, White & Long, 19]. Finally a substance having a biological activity similar to the 11-oxygenated adrenal hormones has been recovered from the urine of patients who have undergone operative and other damaging procedures [Shipley, Dorfman & Horwitt, 19; Venning, Hoffman & Browne, 19]. Although the evidence that activity of the adrenal cortex and excretion of adrenal cortical hormones takes place in response to various damaging stimuli seems fairly convincing, there was no proof that the hormones thus secreted actually protected the organism or altered the protein metabolism. In fact, in a paper recently received, Ingle, Ward & Kuizenga [197] report that although after leg fractures in the adrenalectomized rat an increase in nitrogen excretion does not take place, it does so if the animal is maintained on replacement therapy with cortical extract at a basal level (i.e. where there is no possibility of an increased supply of cortical hormones).

2 0 R. L. NOBLE AND C. G. TOBY During studies on nitrogen metabolism in the rat after trauma it was noted that a large and consistent increase in nitrogen excretion followed an amount of trauma considerably less than that necessary to cause death [Noble & Toby, 1976]. Although it was possible that the protein breakdown was caused by adrenal cortical hormones liberated in response to the trauma, this seemed unlikely since even large doses of an active adrenal cortical extract were followed by comparatively small increases in excreted nitrogen. It was decided therefore to attempt to ascertain what role the adrenal glands play in increasing the urinary nitrogen. In the initial experiments the nitrogen excretion of normal and adrenalectomized rats was compared before and after trauma, and the effect of treatment with adrenal cortical extract in similar groups of rats determined. In other experiments changes in urinary nitrogen excretion have been correlated with alterations in blood non-protein nitrogen (n.p.n.). The effects of two other substances, adrenaline and ascorbic acid, have also been studied. METHODS Hooded male rats raised in the laboratory and weighing g. at the time of operation were used. They were fed a diet containing 15 % casein and % yeast, found adequate for normal growth and previously described for use in nitrogen-excretion experiments [Noble & Toby, 1976; Toby & Noble, 197]. Except where indicated, all the adrenalectomized animals used were adequately maintained on 0-9% sahne; in a few cases glucose was added to make a 10% solution. About a week after the experiment the rats were put on water, to check whether adrenal insufficiency was severe enough to cause death. About half of the rats of the above size in this colony survived adrenalectomy without receiving additional salt. The usual criteria of absence of pituitary function and inspection of the sella at autopsy were used to check the completeness of hypophysectomy. Trauma was applied by two methods. Limb ischaemia was produced by clamping the hind legs as described by Haist & Hamilton [19]. In a few experiments drum trauma was applied according to the method of Noble & Collip [19], but, after exposure to each 100 turns in the drum a rest interval of 5 min. was interposed. Normal animals withstood a total of 1000 turns of such interrupted trauma without mortality [Toby & Noble, 19]. Animals were treated with adrenal cortical extract ACE (Connaught Laboratories0 dog units per ml.), deoxycorticosterone acetate in oildca, adrenaline (Parke Davis 1 : 1000), and ascorbic acid. During the urine collections, which were begun immediately after the trauma, the animals were placed in individual Hopkins metabolism cages and received no food. The cages were placed on large funnels and the usual precautions taken to avoid faecal contamination or loss of nitrogen. The collection was divided into two periods of 10 and 1 hr. and was not prolonged beyond hr. for fear of death in the operated animals. In some experiments with intact animals the collection was extended for another 10 hr. Determinations of total nitrogen and... were done by the micro- Kjeldahl method, n.p.et. estimations were made on blood obtained by heart puncture. The volume of urine was recorded for each period. In the results reported, however, only the total excretion of nitrogen is given, expressed in relation to body weight at the beginning of the experiment. simultaneously and the results averaged. In most cases groups of to 6 rats were run there was individual variation Although

3 ADRENALS AND PROTEIN CATABOLISM 05 in the control experiments with intact animals, the average values obtained from groups of to 6 rats were almost identical for non-traumatized animals, and varied at most +1 mg. after trauma. RESULTS Effect of adrenal cortical extract on nitrogen excretion of normal and traumatized rats Cortical extract was administered to normal rats, and to rats that were traumatized either by the drum or the clamp method. In Table 1 it may be seen that ACE even in large doses caused an increase in nitrogen excretion of not more than 17 mg./100 g. in hr. Although this change was consistently found, it was less than half that resulting from moderately severe trauma. ACE given to animals that had received drum trauma produced little or no alteration in the increase in nitrogen output. In a few experi ments with clamped rats ACE treatment gave inconsistent results, but the number of animals used was too small for comparison. Table 1. Effect of adrenal cortical extract on nitrogen excretion of non-traumatized and traumatized intact rats No. of excretionf rats Form of trauma Treatment* (mg./100g./hr.) 7 ACE 1 ml. subcutaneously hourly 1 ( 0 dog units) = 6 Drum 1000 turns interrupted Drum 1000 turns interrupted ACE 1 ml. subcutaneously hourly 11 ( 0 dog units) = 1 Clamps hr. 111 Clamps hr. ACE. 1 ml. subcutaneously hourly 105 Clamps hr. ACE 1 ml. subcutaneously hourly 11 repeated at 1 hr. * Begun at start of collection period. f Ranges were in all cases within + 1 mg./100 g./ hr. of the mean. Nitrogen excretion of adrenalectomized rats A series of adrenalectomized animals was tested at intervals of from 15 min. to 1 days after operation and the results are shown in Table. Table. Nitrogen excretion of No. of rats non-traumatized adrenalectomized rats Time after excretion ' adrenalectomy (mg./100 g./ hr.) 15 min. 55 (9-5) * hr. 55 (9-59) 5 6 days 5 days 6 (69-9) 5 (67-9) 7 days 1 (7-9) 10 days 7 (60-7) days 7 (6-) 5 19 days 7 (67-1) 5 7 days 6 (60-79) 5 1 days 6 (-5) 6

4 06 R. L. NOBLE AND C. G. TOBY Immediately following removal of the adrenal glands there appeared to be a re duction in nitrogen excretion from the level of 6 mg./100 g. for control unoperated animals to 55 mg./100 g. After -5 days the excretion was somewhat elevated (6 mg./100 g.) and thereafter there was a gradual return to normal values over a period of weeks. Although the average results of groups of rats showed this change, considerably more individual variation occurred in these animals than in intact ones, particularly at the time when the average output was highest. Nitrogen excretion of traumatized adrenalectomized rats Because of the susceptibility of the saline-treated adrenalectomized rat to trauma little more than half of such animals survived after hr. clamping [Noble & Toby, 197a]. In some of the experiments, therefore, the periods of clamping were shorter. The nitrogen excretion of adrenalectomized rats after trauma is shown in Table and compared with that of intact controls and of animals in which only one adrenal gland was removed. No. of rats Table. Nitrogen excretion of traumatized adrenalectomized rats Time after adrenalectomy (Intact controls) 11 (Intact controls) (Intact controls) One adrenal removed just before clamping 6 One adrenal removed day 17 before clamping 15 min. 15 min. -7 days 5 days 7 days 7 days days Duration of clamping (hr.) 1 1 Treatment Saline and glucose Saline and glucose Saline and glucose Saline Saline Saline Saline Saline and glucose Salineconcentration increased to 1-5% for 1 hr. preceding experiment excretion (mg./loo g./ hr.) 10 (90-11) 100 (9-111) 67 (6-70) 97 (9-110) 10 (95-1) 56 (5, 59) 0 (7-) 77 (6-9) 90 (6, 9) 6 (5, 71) 59 (-71) 75 (7-75) When the period of clamping was only 1 hr. there was little change in nitrogen excretion in intact rats (cf. Table 1), and in animals adrenalectomized and 7 days before clamping of l\ hr. duration the nitrogen excretion, although higher than in intact controls, was no higher than in undamped adrenalectomized rats. After hr. clamping the average urinary nitrogen excretion differed little from that of untraumatized adrenalectomized rats (Table ), but there was a greater individual variation in nitrogen excretion than in intact rats and an occasional animal showed an increased nitrogen output. The removal of only one adrenal gland did not alter the excretion of nitrogen after trauma. Following the experiment, animals that survived were allowed a few days for recovery, and were then given water to drink instead of 0-9 % NaCl. About half of these animals died, a proportion which is in keeping with that expected for this colony. Rats that survived, presumably because of accessory adrenal tissue, did not show any greater nitrogen excretion than did those that died of adrenal insufficiency.

5 ADRENALS AND PROTEIN CATABOLISM 07 Effect of adrenal cortical extract on the nitrogen excretion of adrenalectomized and traumatized adrenalectomized rats In Table the effect of treating adrenalectomized rats with ACE or DCA is shown and the results compared with those obtained when such rats were also traumatized. Table. No. of rats 5 Effect of adrenal cortical extract on nitrogen excretion of non-traumatized Time after adrena lectomy (days) and traumatized adrenalectomized rats Duration of clamping (hr.) Treatment DCA 1 mg./day DCA 1 mg./day DCA 1 mg./day for last days Saline throughout and DCA 1 mg./day for last days Saline until last days, DCA 1 mg./day for last days ACE 0-5 ml. t.i.d. ACE 0-5 ml. b.i.d. Saline and ACE 0-5 ml. t.i.d. Salino and ACE 0-5 ml. 7 on day of exp. Saline throughout. ACE 0-5 ml. twice on day before and q.i.h. 6 on day of exp. DCA in oil and ACE were injected subcutaneously. excretion (mg./100 g./ hr.) 70 (6-7) 7 (69-77) 106 (10, 109) 79 (66-9) 5 (7-6) 7 (66-76) 55 (1-6) (-96) (7-9) 7 (, 9) 90 (7-9) 71 (60-77) 106 (9-16) 7 (6-6) 10 (6-1) 9 (79-11) 67 (57-79) 1 (7-5) Treatment with DCA did not auow the normal response in nitrogen excretion to occur after trauma, except in one experiment where only two animals were used. In a number of experiments in which ACE was used, rats showed an increased nitrogen excretion after trauma. The administration of 0-5 ml. three times daily as a maintenance dose, without sahne, was apparently insufficient to allow the normal increase in urinary nitrogen after hr. clamping, but nevertheless allowed the animals to withstand this amount of trauma. When rats were maintained on saline and the above dose of ACE daily the excretion following trauma was approximately the same as that of adrenalectomized control animals. However, when larger doses of ACE were given (0-5 ml. twice on the preceding day and six times during the first collection period) the nitrogen excretion rose, achieving approximately normal values in the traumatized groups used 10-1 days after operation. Control animals similarly treated but not clamped did not show any increase in nitrogen output.

6 0 R. L. NOBLE AND C. G. TOBY Changes in blood non-protein nitrogen and nitrogen excretion after trauma In a number of experiments the level of n.p.n. in the blood was determined to correlate this with nitrogen excretion. Table 5 shows the blood n.p.n. of intact rats at different intervals after clamping. No. of rats Table 5. Duration of clamping (hr.) li Nitrogen excretion and blood non-protein nitrogen after trauma None None None None Treatment excretion (mg./100 gv hr.) Intact rats 9 (5, 9) Adrenalectomized rats* 1- hr. 5 (6-67) 0-9% NaCl 7 (6-) 0-9% NaCl 7 (66-0) ACE 0-5 ml. 7 during exp. (7-9) 0 9% NaCl 95 (70-117) 0-9% NaCl 0-9% NaCl 9 (6-97) ACE 0-5 ml. b.i.d. 55 (1-6) * -7 days after operation. Blood n.p.n. (mg./100 ml.) -9 hr. 56 (5-61) 99 (-10) hr. 5 (50-5) 5 (6, 59) 51 (5-60) 9 (-7) 6 (-) (0-5) Ill (91-160) The n.p.n. did not change in intact rats in response to the trauma, although the nitrogen excretion was increased. Adrenalectomized rats (-7 days after operation) were clamped for \\ hr., some of the animals being treated with ACE. There was very little change in urinary nitrogen and the n.p.n. values were slightly below normal. When the clamps were applied for hr., however, marked alterations were found. The n.p.n. rose in all animals that died within the hr. and up to 9 hr. after release of the clamps, even though small amounts of urinary nitrogen were excreted. Three animals that survived the experiment excreted increased amounts of nitrogen in response to trauma, and did not show a high n.p.n. A group of animals maintained on small doses of ACE did not excrete excess nitrogen after trauma, as was found in some of the earlier groups of animals similarly treated and listed in Table. However, all these rats showed a large rise in n.p.n. Apparently, protein breakdown occurred levels of n.p.n. in those that died soon after trauma. In some untreated animals excretion did occur. Even after a maintenance in these animals and was manifest by high dose of ACE that enabled the animals to withstand trauma, urinary nitrogen was not increased, but the blood n.p.n. was high. Larger doses of ACE, as noted previously, allowed the excess nitrogen to be excreted. Effect of adrenaline and ascorbic acid on nitrogen excretion In view of the relation of adrenaline and ascorbic acid to the function of the adrenal gland some experiments were conducted to see whether these substances might affect nitrogen excretion. The results are listed in Table 6.

7 Table 6. No. of rats ADRENALS AND PROTEIN CATABOLISM 09 Effect of adrenaline and ascorbic acid on nitrogen excretion of intact rats Duration of clamping (hr.) None excretion (mg./100 g.) Treatment* hr. hr. 6 9 ' Adrenaline 1 : 1000, 0-0 ml./kg. subcutaneously 7 Adrenaline 1 : 1000, 0-15 ml. i.p. 95 Adrenaline 1 : 1000, 0-50 ml./i.p. 105 Adrenaline 1 : 1000, 0-50 ml./i.p. Ill Ascorbic acid 50 mg. by stomach tube 51 6 Ascorbic acid 50 mg. subcutaneously q.i.h. 5 7 Ascorbic acid 50 mg. subcutaneously q.i.h.. 77 ACE q.i.h. 5 None Ascorbic acid 50 mg. subcutaneously q.i.h. 105 Ascorbic acid 50 mg. by stomach tube on day pre- 9 1 ceding experiment and again after removing clamps * Begun at start of experiment except where specified. Adrenaline given to normal rats increased nitrogen excretion to an extent pro portional to the dose injected. With the largest dose used the increased loss of nitrogen was as great as that occurring after the forms of trauma previously described (Table 1). Ascorbic acid administered to normal rats lowered nitrogen excretion. This effect was especially marked when the urine collection was extended a further 10 hr. making the total period hr. Over this time untreated, control rats excreted 9 mg./100 g. compared with 6 and 7 mg./100 g. in treated rats. When ascorbic acid was given in addition to ACE some reduction in the expected nitrogen excretion took place. When ascorbic acid was given to animals clamped hr. there was a reduction in nitrogen excretion, especially over a hr. period, the value of 1 mg./100 g. for hr. being some 5 mg./loo g. less than the value obtained for untreated, clamped rats. Nitrogen excretion of hypophysectomized rats Because of the trophic control of the adrenal cortex by the pituitary gland thought of interest to examine the nitrogen excretion of hypophysectomized rats. No. of rats Table 7. Time after operation Immediately hr. hr. lihr. hr. hr. days 6 days weeks weeks weeks 6 weeks Nitrogen excretion of hypophysectomized rats Duration of clamping (hr.) li li Treatment* ACE 0-5 ml. subcutaneously hourly 6 ACE 0-5 ml. subcutaneously hourly 6 ACE 0-5 ml. subcutaneously hourly 6 Begun at start of experimental period. it was excretion (mg./100 g./ hr.) 7 (69, 7) 65 (6, 66) 6 (57-66) (79-9) 79 (76-) 69 (5-97) 10 (10, 115) 10 (100-15) 9 (7, 90) 59 (56, 61) 76 (7-) 7 (7-9)

8 10 R. L. NOBLE AND C. G. TOBY Four to six days after removal of the pituitary gland the nitrogen excretion rose (Table 7). This was about the same time after operation as the highest output seen in adrenalectomized animals. Some increase was still present after weeks, but the values approached normal after weeks. The increased excretion did not appear to be related to the weight loss after hypophysectomy, which was not unduly large. Some hypophysectomized animals were clamped, but no increase in nitrogen excretion was observed (Table 7). Treatment with ACE after clamping did not restore the normal nitrogen response. DISCUSSION The experiments that have been described were designed to determine what part the adrenal cortex might play in the increased protein breakdown occurring after trauma. Initially the urinary output of nitrogen was considered an indication of protein catabolism in the animal. However, because of the inability of the adrenalectomized animal to excrete the excess nitrogen, it later became necessary to estimate the changes occurring in the n.p.n. of the blood as well as in the urinary nitrogen. A number of workers have studied nitrogen excretion in adrenalectomized rats. Rubin & Krick [196] found such animals to show a negative nitrogen balance, which could be reduced by adequate NaCl therapy. Sandberg & Perla [196], using adrena lectomized rats maintained in good health by dietary measures, noted an increased nitrogen excretion and lowered retention of ingested nitrogen for prolonged periods after operation. Evans [196], Harrison & Long [199] and Long, Katzin & Fry [190] all reported a decreased nitrogen excretion in adrenalectomized rats. The latter workers and Sprague [190] also found that the injection of ACE was followed in both normal and adrenalectomized rats by an increased excretion of nitrogen in the urine. In the results reported in this paper, there seems to be evidence that for a brief period after adrenalectomy nitrogen excretion may be below normal, but that for some weeks thereafter higher values than normal are obtained. After about weeks, the normal level is re-established. The results obtained on injection of ACE agree with those of other workers in that an increased excretion of nitrogen takes place. Relatively httle experimental work, however, has been done on the nitrogen excretion of adrenalectomized animals after exposure to trauma. In agreement with the observations of others, it was found that after two different types of trauma in the intact rat, a consistent elevation in urinary nitrogen occurred [Noble & Toby, 1976]. The amount of nitrogen excreted after only moderate amounts of trauma was about double that produced by relatively large doses of ACE in normal animals. Also when ACE was given to traumatized animals, it was not possible to increase the urinary nitrogen output. These observations did not appear to support the sug gestions, previously discussed, that under the stimulus initiated by trauma, a secre tion of the adrenal cortex is induced which causes increased protein breakdown and a resulting loss of nitrogen in the urine. Experiments in which treated and untreated adrenalectomized animals were subjected to trauma were necessary to determine the role of the adrenal in protein catabolism. Difficulty, however, was experienced because of the marked susceptibility to trauma of the adrenalectomized rat, even when maintained in good health by salt. Apparently clamping the hind legs for 1J hr., a procedure which most adrenalecto mized rats could withstand, was not sufficient to cause an increased nitrogen excre-

9 ADRENALS AND PROTEIN CATABOLISM 11 tion, or to elevate the blood n.p.n. A number of animals did survive hr. clamping, and in this case, although the average nitrogen excretion was not increased, it was noted that in some animals an increase did take place. The explanation of this inconsistency was apparent in later experiments in which estimations of blood n.p.n. were also made. In this case the n.p.n. values were consistently increased in animals that did not excrete excess nitrogen in the urine. In instances where high urinary nitrogen values were obtained, the blood n.p.n. was normal. These results therefore indicate that after trauma the adrenalectomized as well as the intact rat shows a breakdown of protein. In most cases, however, there is retention of nitrogen and only in animals with good kidney clearance does a high excretion of nitrogen take place. Animals that do not excrete the excess nitrogen nevertheless, after the usual preliminary few hours of anuria, excrete a normal volume of urine. Although adrenalectomized rats treated with ACE tolerate as much trauma as intact animals, with the daily maintenance dose used in the experiments it was found that after trauma a marked rise in blood n.p.n. took place, but that the extra nitrogen was not cleared by the kidney. When larger doses of ACE were given after trauma, an increased excretion of nitrogen of the same magnitude as that occurring in intact animals resulted. These experiments therefore indicate that the adrenal cortex is not essential for the occurrence of protein catabolism after trauma, but that adequate amounts of adrenal cortical extract are, however, necessary in order that the kidney may excrete the nitrogenous end-products. There seems no evidence from these results that the adrenal cortex is stimulated by trauma in order that its hormones may be used in the protein catabolic process. In a recent paper, Ingle et al. [197] have described balance experiments on adrenal ectomized rats, using a forced-feeding technique to ensure a constant intake. They noted that after leg fractures an increased urinary nitrogen excretion did not take place. An increased breakdown of protein was not, however, ruled out, since blood n.p.n. estimations were not done. After suitable treatment with cortical extract a normal nitrogen excretion was obtained in response to trauma. They concluded that the negative nitrogen balance was not caused specifically by an increased secretion of the cortical hormones. Large doses Adrenaline was found to cause an increase in urinary nitrogen. approaching toxic levels were required to bring about an increase similar to that obtained after the amount of trauma used in our experiments. Ascorbic acid, on the other hand, appeared to depress nitrogen excretion and to diminish markedly the excess nitrogen loss resulting from trauma. Curiously enough, this substance was more effective than various proteins and amino-acids, which might be expected to cause a reduction in nitrogen excretion after trauma [Noble & Toby, 197 c]. Hypophysectomy, in the few experiments presented, produced more exaggerated changes in nitrogen excretion than did adrenalectomy, but the peak of excretion in both types occurred at the same time after operation. Treatment with ACE in amounts effective for replacement therapy in adrenalectomized rats was not adequate to restore the normal excretion of urinary nitrogen after trauma in the hypophys ectomized animal. The evidence which this paper presents of a physiological role of the adrenal gland in the protein catabolic response occurring after trauma is essentially negative. One

10 1 R. L. NOBLE AND C. G. TOBY cannot but wonder what function the increased excretion of the adrenal cortex serves It after trauma, since the evidence is so suggestive that the organ is stimulated. seems certain that an increased secretion of adrenal hormones does not improve the tolerance of a normal animal to traumatic procedures, nor is it necessary for the breakdown of protein. It is possible that its function is more specifically related to the breaking down of lymphocytes and release of antibodies [White & Dougherty, 196] or to its action in aiding the animal in the development of resistance to trauma [Noble, 19]. SUMMARY The urinary excretion of rats given large doses of adrenal cortical extract (0 dog units) did not approach the high level reached after moderately severe trauma. Treatment with adrenal cortical extract did not increase the nitrogen output of traumatized animals. In the adrenalectomized rat the daily nitrogen output dropped slightly after operation and then rose above normal levels, reaching a peak on the th or 5th day and returned slowly to normal over a period of weeks. The urinary nitrogen response to trauma was unaffected when one adrenal only was removed. Bilaterally adrenalectomized animals showed on the average no elevation of urinary nitrogen after trauma, although a response occurred in a few individual cases. Blood n.p.n. values, however, were consistently increased in those not showing increased nitrogen output. Adrenalectomized animals treated with maintenance doses of cortical extract showed no excess urinary nitrogen after trauma, but the n.p.n. of the blood was increased. With larger doses of cortical extract an elevation of urinary nitrogen after trauma was found, comparable with that found in intact rats. The amount of cortical extract used did not affect the nitrogen excretion of untraumatized adrenalectomized animals. Protein catabolism after trauma was apparently not dependent on the adrenal cortex. Adrenaline in large doses increased the excretion of nitrogen, the response being roughly proportional to the dose. Ascorbic acid depressed the nitrogen output of normal and traumatized rats. A small group of hypophysectomized animals showed the same type of elevation as was found in adrenalectomized rats. No increase in urinary nitrogen occurred after trauma, even when adrenal cortical extract was administered. This work was supported in part by the National Research Council, Ottawa. The authors wish to thank Dr J. B. Collip for his helpful interest and Messrs E. Anderson, E. Peterson and R. Rasmussen for valuable technical assistance. REFERENCES Albright, F. [19]. The Harvey Lectures. Cuthbertson, D. P. [190]. Biochem. J., 1. Cuthbertson, D. P. [196]. Brit. J. Surg., 505. Evans, G. T. [196]. Amer. J. Physiol. 11, 97. Haist, R. E. & Hamilton, J. [19]. J. Physiol. 10, 71. Harrison, H. C. & Long, C. N. H. [199]. Amer. J. Physiol. 16, 56. Howard, J. [195]. Arch. Surg. 50, 166. Ingle, D. J., Ward, E. O. & Kuizenga, M. H. [197]. Amer. J. Physiol. 19, 510.

11 ADRENALS AND PROTEIN CATABOLISM 1 Long, C. N. H., Katzin, B. & Fry, E. G. [190]. Endocrinology, 6, 09. Noble, R. L. [19]. Amer. J. Physiol. 1, 6. Noble, R. L. & Collip, J. B. [19]. Quart. J. Exp. Physiol. 1, 17, 01. Noble, R. L. & Toby, C. G. [197«]. Canad. J. Res. E, 5, 19. Noble, R. L. & Toby, C. G. [1976]. J. Physiol. (in the Press). Noble, R. L. & Toby, C. G. [197c]. J. Physiol. (in the Press). Rubin, M. I. & Krick, E. T. [196]. J. Clin. Invest. 15, 65. Sandberg, M. & Perla, D. [196]. J. Biol. Chem. 11, 5. Sayers, G., Sayers, M.., White,. & Long, C. N. H. [19]. Proc. Soc. Exp. Biol., N.Y., 5, 00. Selye, H. [196]. J. Clin. Endocrinol. 6, 117. Shipley, R.., Dorfman, R. I. & Horwitt, B. N. [19]. Amer. J. Physiol. 19, 7. Spraguo, R. G. [190]. Proc. Mayo Clinic, 15, 91. Toby, C. G. & Noble, R. L. [19]. Canad. J. Res. E,, 79. Toby, C. G. & Noble, R. L. [197]. Canad. J. Res. E, 5, 16. Venning,. H., Hoffman, M. M. & Browne, J. S. L. [19]. Endocrinology, 5, 9. White,. & Dougherty, T. F. [196]. Ann. N. Y. Acad. Sci. 6, 59.