THE EFFECT OF SALICYLATES ANDADRENOCORTICOTROPICHORMONEUPONTHE MISCIBLE POOLOF URIC

ACID IN GOUT1

By JEAN D. BENEDICT, PETERH. FORSHAM,MARCELROCHE, SIDNEYSOLOWAY,ANDDEWITT STETTEN, JR.

(From the Division of Nutrition and Physiology, the Public Health Research Institute of theCity of New York, Inc., New York; and the Medical Clinic, Peter Bent Brigham

Hospital and the Department of Medicine, Harvard Medical School, Boston)

(Submitted for publication May 15, 1950; accepted, May 22, 1950)

In a previous report (1) were described the re-sults of experiments in which isotopic uric acidwas injected intravenously into normal and goutyhuman male subjects. The purpose was to as-certain the magnitude of the "miscible pool," thatquantity of uric acid present in the body capableof prompt mixing with the injected material, andthe rate of its turnover. The results indicated thatthere are some 1200 mg. of miscible uric acidnormally present, a finding in accord with thatof Geren and associates (2), that between 50and 75 % of this is each day replaced by newlyformed uric acid and that this latter quantityexceeds the quantity excreted daily in the urine,suggesting the occurrence of limited catabolismof uric acid in man. In the gouty subjectsstudied, the magnitude of this miscible pool ex-ceeded the normal levels by as much as 15 fold.Indeed, so large was the quantity of promptlymiscible uric acid as to indicate that at least aportion of this material must reside in the solidphase rather than in solution in body fluids.

In the present study 2 we have extended our ob-servations on the amount and distribution of mis-cible uric acid in the gouty patient and have in-vestigated the effects upon these quantities of someof the therapeutic agents commonly employed inthis disease. The effect of ACTH3 on the normalsubject has also been studied.

MATERIALS ANDMETHODS

The preparation of isotopic uric acid labeled in the oneand three positions with N', the isolation of uric acid

1This study was aided in part by grants from theDivision of Endocrinology, the United States PublicHealth Service, and Armour and Co.

2 preliminary report of this work has appeared (3).8We are indebted to Dr. John R. Mote, Medical Di-

rector, the Armour Laboratories, Chicago, for the ACTHused in these studies.

from the urine samples and isotope analysis have allpreviously been described (1). The only novel chemicalprocedure was the analysis of a tophus excised from sub-ject A. L. on the ninth day of his third experiment. Thisspecimen when dried in vacuo over P205 weighed 6.8 gm.In the expectation of dissolving successive laminae ofuric acid, the tophus was then placed in the thimble ofa Soxhlet apparatus over boiling water and extractedfor three periods of 24 hours each, the contents of theflask being replaced by fresh water after each period.An aliquot of each extract was analyzed for uric acid bythe method of Forsham and co-workers (4) and pureuric acid was isolated from the remaining extract forisotope analysis by the same method previously employedin the isolation from urine (1). The residue of thetophus was boiled in 500 ml. of 0.07 MLi2COa for onehour, the solution filtered, and analyzed for uric acid.The same mathematical treatment of results has beenemployed as was described in the earlier report (1).

Both the normal and gouty subjects were maintainedin slightly positive nitrogen balance on constant dietscalculated to contain purines equivalent to 2.4 to 3.1 mg.of uric acid per day. It was found that a preliminary pe-riod of at least three days on this diet was required toachieve a reasonably constant urinary uric acid out-put. Sterile solutions of the lithium salt of isotopic uricacid were prepared and injected intravenously as pre-viously described (1). The injection was carried outover a period of 30 minutes and the midpoint was takenas zero time in the subsequent calculations.

The total urine output of each subject was collectedin 12 hour portions, and each sample was analyzed foruric acid by the method of Forsham and colleagues (4).From 94 to 98% of the chromogenic material in urinedetermined by the method was found to be destroyed byuricase. Pending isolation of urinary uric acid for iso-topic determination, the samples were preserved byfreezing.

SubjectsW. A. was a normal 22 year old male medical student

with no familial history of gout. He was placed on a con-stant purine-low diet prior to the intravenous injection ofisotopic uric acid. On the second and third day follow-ing this infusion 25 mg. of ACTH were administeredintramuscularly every six hours to a total of 200 mg.

1104

1105EFFECT OF AGENTSON MISCIBLE URIC ACID POOL IN GOUT

; . , < c;5 ' i ; .. . .. . .. ... ... ......... <~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~... ..

= x t; s F .. ... ... . - 8 ;'~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.....

FIG. 1. A. L. LEFT HANDAND LEFT KNEENote the large tophaceous deposits in the proximal portion of the middle finger and over the patella.

A. L., a 64 year old former hotel manager of NorthItalian extraction who was suffering from severe chronictophaceous gout, had previously been studied by thistechnique (1). He was subjected to two further in-vestigations; first, after a period of scant and irregu-lar medication, then again after a protracted course ofsalicylates. The possible effect of ACTHwas exploredduring the former of these two experiments, that ofcolchicine during the latter.

First admission-In 1924 (age 39), the patient broketwo right metatarsal bones. Seven days after the ap-plication of a plaster cast, the patient experienced anacutely red and painful swollen right wrist and returnedto the hospital for treatment. The pain continued forseveral weeks. Because of the possibility that the in-flammation of the wrist may have been due to second-ary infection, the patient's tonsils were removed. Thepain slowly subsided after this. No determinations ofuric acid were done.

From 1924 to 1937 the patient enjoyed excellent health,living on a very rich diet with frequent partaking of an-chovies, caviar, sweetbreads, foie gras and a moderateintake of alcohol, all incidental to his occupation.

In the winter of 1937 he experienced his second attackof joint pain, accompanied by swelling and redness, thistime of the right knee. A diagnosis of gout was madeat an outside hospital. The patient was placed on a lowpurine diet which he has followed ever since.

From 1937 to 1940 there were many and frequent at-tacks of arthralgia, each one lasting for from one to twoweeks. Deposits began to develop around the joints andby 1940 motion of practically all the joints of the ex-tremities was severely limited.

From 1940 on the pain was only rarely acute, but therewas constant joint ache and impaired mobility; the pa-tient was reduced to a state of chronic invalidism.

Approximately five months before his second admissionhe was again seen at an outside hospital where he wasplaced on a regimen of aspirin 4.8 gm. to be taken everythird to fourth day.

Outside of the history of high purine intake, there wasnothing of significance in the patient's past history.There was no familial background of gout or any otherjoint disease.

Second admission, Feb. 4, 1949-Physical examinationrevealed a well nourished (wt. 75 kg.) alert and pleasantman. Firm subcutaneous deposits could be plainly seenand felt around both first metatarso-phalangeal joints,over the patellae and around several of the finger joints(Figure 1). Over the olecranon areas, on both sides,there were well healed scars at the sites where largetophaceous deposits had been excised at another hos-pital. A toe removed at this admission showed a mas-sive tophus (Figure 2).

X-ray studies showed many areas of cystic destructionof the bones characteristic of gout. Blood and urine-

BENEDICT, FORSHAM, ROCHE, SOLOWAY, AND STETTEN

FIG. 2. A. L. CROSS SECTION OF THE PATIENT'S LEFTFIRST METATARSAL

The bone has been destroyed by a large tophus.

studies were normal except for a slight normocytic ane-mia (hematocrit 38%) and a serum uric acid of 10 mg. %o.Maximum urea clearance was 135 %0 of normal and PSPexcretion was normal at 32% in 15 minutes and 70% intwo hours. The blood urea nitrogen was 19 mg. % onadmission, later fell to 11 mg. % on two occasions. Itwas never found to be elevated during later admissions.

The first experiment with isotopic uric acid was car-ried out during this admission with the patient on apurine-low diet. Thereafter the patient received a sixday course of ACTH (40 mg./day) with good clinicalimprovement associated with a transitory increase inuric acid excretion (Figure 3) and a fall in serum uricacid from 10.1 to 5.3 mg. %.

The patient was discharged on a purine-low diet andwas told to take aspirin and colchicine as needed. Thishe did only infrequently, since he had a feeling that theyhelped him very little (Table I).

TABLE I

Summary of treatment of A. L.

Date Period Daily medication

10/10/48- 2/10/49 Before first study Aspirin 4.8 gm. everyfour days

2/10/49- 2/17/49 First isotope study

2/17/49- 2/23/49 ACTH40 mg.2/23/49- 5/27/49 ItrmAspirin and colchicine2/23/49-5/27/49Interim irregularly

5/27/49- 6/21/49 No treatment

6/21/49- 6/28//49 Second isotope study6/23/49 ACTH80 mg.6/24/49 ACTH80 mg.

6/28/49- 7/ 5/49 ACTH30 mg.7/ 5/49- 8/23/49 Interim Aspirin 3.6 gm.8/23/49- 9/20/49 Aspirin 2.4 gm.9/20/49-11/ 1/49 Aspirin 2.7 gm.

11/ 1/49-11/ 6/49 Third isotope study11/ 3/49 Colchicine 4.8 mg.11/ 4/49 Colchicine 4.8 mg.11/ 9/49 Tophus removed from

ankle

Third admiiissionz, May 24, 1949-The patient was ad-mitted for a few days for a study on an artificial kidney.During this study he received 80 mg. of ACTH.

Two or three days after discharge, the patient experi-enced one of his rare acute gouty attacks involving theright first metatarsal joint and leading to a discharge ofgouty matter through a break in the skin resulting insecondary infection which was treated conservatively.

One month prior to his fourth admission the patientstopped all salicylate and colchicine medication (TableI).

Fourth admission, Junie 15, 1949-The patient was

treated with penicillin alone soon after admission. Thesecond isotopic uric acid study was performed during thisadmission. ACTHwas given intramuscularly on the sec-

ond and third days following the infusion of isotopic uricacid, 80 mg./day in four divided doses. The patient was

discharged on July 19, 1949 and was instructed to take3.6 ggm. of acetylsalicylate daily at home. This dosehad to be reduced to 2.4 gm. daily as the patient devel-oped some epigastric pains and experienced two episodesof melena because of the reactivation of an old duodenalulcer.

Fifth admnissioni, October 24, 1949-After a six day pe-

,00

1,400

1I300

,200

1,100

URINARY 0,00URIC ACID

900(mg/24hfr)

700

600

400

300

200

Pk

DRUG

DAYS

EFFECT OF VARIOUS DRUGSON

URIC ACID EXCRETION64 CHRONIC GOUT4~~~~~~~~~ n

U.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ACTS4Occgq4A~~~~~~~~~~~~p, 6g's qO Coich 4 R~~~~~~~~~~~IIg

1234567S9'O" 123456?89'O 23456?~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

FIG. 3. A. L. URINARY URIC AcID EXCRETIONThe experiments with ACTH and with acetylsalicylic

acid were carried out on the first admission. Full oraldoses of salicylate produced a prompt maximal rise ofurinary uric acid which lasted for 24 hours after dis-continning the drug. ACTH produced a smaller, more

gradual rise, with a prompt return to basal levels afterstopping the administration. The experiment with colchi-cine was performed seven months after the first two ex-

periments, at a time when the "miscible pool" had beenmarkedly reduced.

1106

EFFECT OF AGENTSON MISCIBLE URIC ACID POOL IN GOUT

1000

MCX4HR70Q -

MG

7eJ I

LN I -2

0 1 2DAY!

FIG. 4. A. L.-2. MEASURETOF URIC ACID AFTER A PER80 mg. of ACTHwere acd

riod without medication the twas carried out. During thimg./day in four divided doseand third days after the inilabeled uric acid. The paticolchicine overdosage on thilowing the start of this expethe left ankle was removed s

There were no obvious clintimes of the three isotope e:peared no different in sizesoftening of the tophi was obwas given ACTH but thereNo untoward effect was obsetion of intravenous uric acidsion when, shortly after the bpatient developed nausea, voiafter developed a generalize(jection was continued, the papyribenzamine immediately"tubing reaction" disappeared

RESU

The results of the first eject A. L. have previousl)

Figures 4 and 5 are recorded the analytical valuesURINE URIC ACI obtained in the second and third studies of this pa-

I____1 tient. As in the earlier report, the concentrationsof isotope in urinary uric acid (I) have been

SE£RUJMURIC ACID plotted against time (days) on semilogarithmicAL. (2 coordinates because it was shown that under these

SLOPE=---363 DAY circumstances, a straight line would be obtainedwhose slope (- K) was numerically equal to thefraction of the pool replaced per day by new uricacid. The intercept (ln I(,) is then the naturallogarithm of the isotope concentration of the mis-

3 4 6 7 cible uric acid at the moment of mixing. From thiss quantity, together with the quantity and isotopeMENTOF THE MISCIBLE POOL concentration of the uric acid injected, the mag-IOD WITHOUTTREATMENT nitude of the miscible pool has been computed.ministered on days 2 and 3. In Table II are given the summaries of the re-

sults of three experiments conducted on this sub-hird isotopic uric acid study ject. The miscible pool contained about 18,000is experiment coichicine, 4.8~s, was given on the second mg. of uric acid at the time of the first experiment.travenous administration of During the four and one-half months interveningient developed no signs of between the first and second experiments, the pa-s regimen. Nine days fol-riment a large tophus over 500_

;urgically for isotopic study. MG/24 HR URINE URIC ACIDical differences noted at the 200

xperiments. The tophi ap-

or consistency. A distinct _MGshSEeRreatURIC ACIDiserved each time the patient 7-_

was no reduction in size.rved during the administra-

I, except on the third occa-eginning of the infusion, themited once and soon there-d urticarial rash. The in-tient was given 100 mg. ofand all symptoms of this

within half an hour.

rLTS

:xperiment on gouty sub-f been reported (1). In

LNI 0.'

C

A L (3)SLOPE = - 0296 DAY

I INTERCEPT- 1.34- LN 383

'- I--L

0 1 2 3 4 5 6 7DAYS

FIG. 5. A. L.-3. MEASUREMENTOF THE MISCIBLEPOOL OF URIC ACID AFTER PROLONGEDTREATMENTWITHSALICYLATES

Colchicine 4.8 mg. q. d. was administered on days 2and 3.

TABLE II

Injection of isotopic uric acid into gouty patient A. L.*

Experi- a =dose =injected atilof A =miscible KKA= C -body Aconc.in body levelment injected Ii=netd intercept pool K soe turnover weight waternbdy lee

mg. at. % at. % mg. day-' mg./day kg. mg. % mg. %1 75.0 29.6 0.12 18,450 0.463 8,542 75 35.1 9.64.12 306 29.6 0.29 31,019 0.363 11,260 75 59.1 9.5.A13 300 30.4 3.83 2,081 0.296 616 75 4.0 10.24.1

* The size of the miscible pool of uric acid in this subject has been determined on three occasions by the measurementof the dilution of isotope which results when isotopic uric acid is injected intravenously.

1107

BENEDICT, FORSHAM, ROCHE, SOLOWAY, AND STETTEN\

tient received medication inconstantly and duringthe last month of this period no medication was

taken (Table I). At the time of the second experi-ment, the miscible pool had increased to a value of31,000 mg., almost twice the earlier value or ap-

proximately 30 times normal. It is noteworthythat this increase was not accompanied by any

significant change in the serum uric acid concentra-tion (last column, Table II). The figures in thenext to the last column represent the mean con-

centrations of uric acid throughout total body wa-

ter calculated on the assumptions that all the uricacid in the pool is uniformly distributed through-out all the water of the body (0.7 x body weight).In the normal subjects, such a calculation gave val-ues of approximately half the serum uric acid con-

centrations. In the untreated gouty subject, thisvalue is far above the serum level, in the presentinstance far above the expected solubility of uricacid in saturated physiological solution. In thenormal subject it was concluded that miscible uricacid is present in some body fluids in concentra-tions far lower than in plasma, whereas in thegouty subject a large reservoir of miscible uric acidmust be postulated, and in view of its size and therelative insolubility of uric acid in physiologicalsolutions, the bulk of this reservoir would appear

to be in the solid phase.During the three months which intervened be-

tween the second and third experiments, the pa-

tient received aspirin, 2.6-4.0 gm. daily, and al-though continuous analytical data are not avail-able, spot-checking revealed a urinary excretionof uric acid of approximately 300 mg./day over

this subject's basal excretory level. At the timeof the third experiment, his miscible pool of uricacid had contracted to about 2000 mg., about one-

fifteenth of its previous value and about twicethe normal value. This dramatic response totherapy was not accompanied by any significantfall in the serum uric acid concentration. It shouldbe noted that there was no clinically obviousdiminution in the mass of palpable and visible tophiduring this interval. As a consequence of thiscontracture of the miscible pool, when the mean

distribution of miscible uric acid throughout bodywater was computed, a concentration lower thanthat in the serum was found just as in the normalsubjects.

On the ninth day of the same experiment, a

TABLE III

The concentrations of N15 in serial extracts of a tophus*

Extract Uric acid N15

No. mg. atom %01 240 0.0192 705 0.0143 465 0.006

Residue 540 0.005

Total 1950

* The tophus was excised on the ninth day of experimentA.L.-3. Its dry weight was 6.82 gm. The pool of uricacid at that time contained 0.27 atom %N".

tophus was excised from the patient's ankle. Atthis time the uric acid in the miscible pool had anisotope concentration (extrapolated) of 0.27 atom%o excess Nl5. By serial extraction of this speci-men, successive laminae of uric acid apparentlywere removed, as is indicated by the progressivedecrease in isotope abundance of the uric acid ex-tracted (Table III). The isotope concentrationeven in the first extract was notably low, aboutone-fourteenth that in the miscible pool, indicatingthat at this time very little of the solid phase uratewas in equilibrium with uric acid in the misciblepool.

The administration of ACTH to subject A. L.during his second experiment resulted in a satis-factory adrenal cortical activation as shown by afall of circulating eosinophils from 1213 to 58/cu. mm. in 48 hours and a uric acid diuresis ofsome 300 mg./day above basal values (Figure4). This urinary loss of uric acid was accompaniedby an appreciable decline in the serum uric acid

00/ 24 NURINE URIC ACID

6 SERUMURCACIDM1G X 3[

W. A.

SLOPE= - 0.592 DAY1I \ INTERCEPT= 174- LN 5.70

LN I0

-I-II I x, I

2DAYS3 4 5 6 7

FIG. 6. W. A. MEASUREMENTOF THE MISCIBLE POOLOFURIC ACID IN A NORMALSUBJECT

100 mg. of ACTHwere administered on days 2 and 3.

1108

EFFECT OF AGENTSON MISCIBLE URIC ACID POOL IN GOUT

from 10.2 to 6.7 mg. %. Had the increase inurinary uric acid resulted from an increase in uricacid production this decline in serum level wouldnot have been expected to occur and an increase inthe rate of fall of isotope concentration in urinaryuric acid would have been anticipated.

In order to obviate any possible masking of theeffect of ACTHupon the pool of miscible uric acidincident to the enormous size of the pool in thispatient, it was decided to repeat this study upon a

normal subject W. A. In Figure 6 are given theresults of this experiment in which ACTH was

given during the course of an isotope study. Therise in urinary uric acid excretion as well as the fallin serum uric acid is in every way comparablewith that previously noted in the gouty subject.The absence of any change in the rate of declineof the isotope values following the administrationof ACTHin this subject is clear evidence that no

great increase in the rate of uric acid productionhad occurred. Such an increase might have beenmasked by the large size of the pool in experimentA. L.-2, but in the present experiment, wherethe pool size was quite small (Table IV) an in-crease in uric acid production sufficient to accountfor the uric acid diuresis should have been obvious.These results therefore strongly support the viewthat ACTHoperates predominantly at a renal leveland they conform with the views and findings ofothers (5-8) as to the mode of action of ACTHand corticoids upon uric acid and explain in partthe mechanism of ACTHin the treatment of gout

(9-12).In the course of the third experiment, subject

A. L. was given 1.2 mg. of colchicine every six hoursfor two successive days without developing signsof toxicity. No significant change in daily uri-nary excretion of uric acid or in its concentra-tion in serum was detected (Figure 5) nor didany change in the slope of the isotope data occur.

TABLE V

Concentration of N'5 in urinary ammonia and urea samples*

Subject Day Ammonia Urea Uric acid

atom % atom % atom %A. L. (1) 1.0 0.001 0.008 0.082A. L. (2) 1.0 0.014 0.020 0.201A. L. (3) 1.5 0.018 0.041 2.450

4.0 0.007 1.103W. A. 0.12 0.009 0.023 5.218

4.5 0 0.024 0.263

* Urinary ammonia and urea have been isolated fromcertain urine samples and their isotope abundances com-pared with those of the simultaneously excreted uric acid.

Whereas Bishop and associates ( 13) have reporteda contracture of the miscible pool of uric acid inresponse to colchicine in two out of three goutypatients, it should be noted that the subjects inwhich this effect was described had received noprevious medication.

When uric acid labeled with N1' was previouslyinjected, small though significant concentrationsof N15 were found in certain samples of urinaryurea and ammonia (1). In the present series wehave again noted the appearance of N15 in urea andammonia following the injection of uric acidlabeled with N'5 (Table V). This is taken tomean that to a limited extent uric acid is catabo-lized in man. The finding of Geren and colleagues(2) that oral administration of similarly labeled uricacid resulted in the appearance of an abundance ofisotope in urea and ammonia suggests that theintestinal flora rather than the tissues of the hostproper may be responsible for this degradation ofuric acid.

DISCUSSION

The wide differences in the quantity of uric acidin the "miscible pool" observed when normal andgouty subjects are contrasted and when the samegouty subject is observed prior and subsequent to

TABLE IV

Injection of isotopic uric acid*

a =doise ecedlo =antiln of A =miscible KA= C=body A/0.7C =mean Mean serumSubject |injected =injected intercept p l K= -slope turnoverA weight conc. in body levelinjected intercept pool turnover weight ~~~~watermg. at. % at. % mg. day-' mg./day kg. mg. % mg. %

W. A. 200 30.4 5.70 866 0.592 513 71 1.7 4.24.5

* Isotopic uric acid has been injected into a normal man, and during the succeeding period the isotope concentrationof his urinary uric acid was followed. ACTHwas administered for two days during this period (Cf. Figure 6).

1109

BENEDICT, FORSHAM, ROCHE, SOLOWAY, AND STETTEN

TABLE VI

Quantities of rapidly miscible uric acid-in fluid compartmentsof normal men*

A D A-D=ESubject In total In plasma In non- Ratio E/D

pool water plasma water

mg. mg. mg.D. C. 1341 224 1117 5.0R. B. 1173 196 977 5.0G. W. 1145 171 974 5.7W. A. 866 152 714 4.7

Mean 1131 186 946 5.1

* The quantity of uric acid in the miscible!poollhas beentaken from the isotope data; the quantity in the plasmahas been calculated from the mean concentration in serumand an estimate of quantity of plasma (0.051 X bodyweight). The difference between these two values is themiscible uric acid dissolved in non-plasma water.

treatment with uricosuric drugs demands that anattempt be made to determine the boundaries aswell as the compartments of this miscible pool.Some steps in this direction can be made if it beprovisionally assumed that the distribution of dis-solved free uric acid betweeni plasma water andremaining body water is determined by the rela-tive sizes of these reservoirs, by membrane distri-bution effects and by lnothing else. Assumingthat these quantities are not markedly influencedby the presence of a gouty diathesis, it follows thatthe ratio of this distribution would be uniform inall our subjects. In the normal subjects thisdistribution may be computed (Table VI). Thequantity of uric acid dissolved in plasma has beencalculated from the average serum concentration,in each case, and from an estimate of plasmaquantity (0.051 x body weight). As there is noindication of uric acid occurring in the normalsubject in any condition other than in solution, thedifference between the total pool uric acid and theplasma uric acid has been taken to represent theuric acid in solution in non-plasma body water.The ratio of these last two numbers indicates thatthere is approximately five times as much uricacid in solution outside of plasma as there is plasmauric acid (Table VI). Included in this table arecalculations from the three normal subjects pre-viously reported (1), as well as normal subjectW. A. described in the present paper.

If this same ratio is now assumed to obtain inthe gouty patients, it is clear (Table VII) thatthe two compartments just considered fall far

short of accounting for all of the uric acid shownto be present in the miscible pools of these sub-jects. That uric acid which is neither in solutionin the plasma water nor in solution in non-plasmabody water we take to represent urates present inthe solid phase yet in mobile equilibrium with uricacid of the pool. It will be seen that it is this frac-tion which is the major variable, increasing withlack of treatment (A. L.-1 -* A. L.-2) anddropping virtually to zero in response to therapy(A. L.-2 -- A. L.-3). This reconistruction ofthe response to salicylate therapy is in accord withthe extremely low isotope concentrations found inthe tophus uric acid (Table III), in view of thefact that the tophus was excised during the thirdexperiment, when, from the figures in Table VIIit would appear that no solid phase urate is in-cluded in the miscible pool.

It must not be supposed, from the foregoing,that the writers contend that all the urate in thesolid phase in patients with tophaceous gout isnecessarily included in the "miscible pool." Insubject A. L. this was clearly not the case, abun-dant tophi remaining after the course of salicylatetreatment, at a time when the entire miscible poolappears to have been uric acid in solution.

One may picture that the outer lay)ers of atophus, comprising recently precipitated urateswhich are still in contact with body fluids are sus-ceptible of rapid resolution and are included in themiscible pool, while the deeper layers, the chalkydeposits of older vintage (cf. Figure 2). no longerin contact with body water, are incapable of reso-lution and are excluded from the miscible pool.

TABLE VII

The distribution of rapidly miscible uric acid in gouty patients*

A D E=5.1DA-DESubject In total In pls aIn no- I oi

pool water plastemra phase

mg. mg. mg. mg.B. S. 4,742 261 1,331 3,150A. L. (1) 18,450 352 1,795 16,303A. L. (2) 31,019 371 1,892 28,756A. L. (3) 2,081 382 1,948 (-249)

* The figures in columns A and D were arrived at as inTable VI. The uric acid dissolved in non-plasma waterwas determined by multiplying the quantity of plasmauric acid by the factor 5.1. The surplus miscible uricacid not contained in either of these two compartmentshas been assigned to the solid phase.

1110

EFFECT OF AGENTSON MISCIBLE URIC ACID POOL IN GOUT

The present findings are in accord with such aview.

The role of salicylates as prophylactic agentsin the control of gout may be inferred from theforegoing discussion. They may fail to preventthe appearance of acute gouty arthritis and indeedGutman (14) has observed the occurrence of suchacute attacks during a course of treatment withsalicylates which was effectively increasing uricacid excretion. The continuous administration ofsalicylates may however be expected to inhibit thegrowth of tophaceous desposits.

SUMMARY

The magnitude of the "miscible pool" of uricacid in a patient suffering from severe chronictophaceous gout has been determined by measure-ment of the dilution of isotope which occurredwhen uric acid labeled with N15 was injected in-travenously. This pool, which increased to a val-ue of about 31 gm., or about 30 times normal, fellto a value of about 2 gm., or approximately twicenormal when the uricosuric doses of acetylsalicylicacid were given.

The effect of ACTHupon uric acid metabolismhas been studied in both gouty and the normal malesubjects. The resultant uricosuria appears to ariseexclusively from an increased renal clearance ofuric acid. Colchicine had no demonstrable effectupon the quantities measured.

It has proved feasible to divide miscible uric acidinto three compartments: 1) In solution in plasmawater; 2) In solution in non-plasma body water;3) In the solid phase. It is predominantly the uricacid in the last of these compartments that is sub-ject to wide excursions in response to therapy.

ACKNOWLEDGMENTS

The authors wish to express their indebtedness to Mrs.Eleanor Schroeder and Mr. Frank J. Rennie for assist-ance in conducting the isotope analyses. They are alsomuch indebted to Mr. Angelo Lippi who acted voluntarilyas the chief subject in these investigations. The authorsalso gratefully acknowledge the constant interest andadvice of Dr. George W. Thorn.

BIBLIOGRAPHY

1. Benedict, J. D., Forsham, P. H., and Stetten, De-Witt, Jr., The metabolism of uric acid in the nor-mal and gouty human studied with the aid of iso-topic uric acid. J. Biol. Chem., 1949, 181, 183.

2. Geren, W., Bendich, A., Bodansky, O., and Brown,G. B., The fate of uric acid in man. J. Biol. Chem.,1950, 183, 21.

3. Benedict, J. D., Forsham, P. H., Roche, NI., Soloway,S., and Stetten, DeWitt, Jr., Pool of miscible uricacid in the gouty human. Federation Proc., 1950,9, 149.

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6. Thorn, G. W., Forsham, P. H., Bennett, L. L.,Roche, M., Reiss, R. S., Slessor, A., Flink, E. B.,and Somerville, W., Clinical and metabolic changesin Addison's disease following the administrationof Compound E Acetate (11-dehydro-17- hydroxy-corticosterone acetate). Tr. A. Am. Physicians,1949, 62, 233.

7. Hellman, L., Weston, R. E., Escher, D. W., andLeiter, L., The effect of adrenocorticotropin onrenal hemodynamics and uric acid clearance. Fed-eration Proc., 1948, 7, 52.

8. Friedman, M., Bernstein, D., and Byers, S. O., Roleof the adrenal cortex in the excretion of purines.Federation Proc., 1949, 8, 52.

9. Hellman, L., Production of acute gouty arthritis byadrenocorticotropin. Science, 1949, 109, 280.

10. Robinson, W. D., Conn, J. W., Block, W. D., andLouis, L. H., Role of the adrenal cortex in uratemetabolism and in gout. J. Lab. & Clin. Med.,1948, 33, 1473.

11. Thorn, G. W., Bayles, T. B., Massell, B. F., Forsham,P. H., Hill, S. R., Jr., Smith, S., III, and Warren,J. E., Studies on the relation of pituitary adrenalfunction to rheumatic disease. New England J.Med., 1949, 241, 529.

12. Wolfson, W. Q., Cohn, C., and Levine, R., Rapidtreatment of acute gouty arthritis by concurrentadministration of pituitary adrenocorticotropichormone (ACTH) and colchicine. J. Lab. & Clin.Med. (Proc. Central Soc. Clin. Research) (inpress).

13. Bishop, C., Garner, W., and Talbott, J. H., Effect ofcolchicine and cortisone on uric acid metabolism ingout. Federation Proc., 1950, 9, 151.

14. Gutman, A. B., Personal communication.

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