EFFECT OF RESORCINOL ON THE THYROID UPTAKE OF I131 IN RATS

855 evidence of.

thyroid deficiency. It is probably relevant that of our two patients with serum-cholesterol levels in the normal range, one (case 1) had had long-standing I severe heart-failure due to rheumatic heart-disease, and the other (case 3) was anaemic. Further, resorcinol,, which, like phenol, is known to be metabolised by theB liver-i.e., eonjugated and then excreted in the urine -may be similarly toxic to the liver. Some such toxic effect may possibly have contributed to the failure of the cholesterol levels to rise with thyroid deficiency. Since resorcinol is known to produce methaemoglobin2emia, its toxic effects may also have caused the anaemia and the other complicating symptoms found in case 3. Further studies are still being conducted with the collaboration of our colleagues on two of these three patients, and fuller details will be published later. Many antithyroid compounds are already known (Astwood et al. 1945). The study by Chesney et al. (1928) of the goitrogenic or antithyroid action of cabbage probably initiated the investigation of such compounds. Marine et al. (1932) afterwards showed that the goitrogenic agent in cabbage is probably a glucosidic compound of an organic cyanide. Later discoveries of clinically important antithyroid agents included those of rape seeds by Hercus and Purves (1936), of sulphonamides by Mackenzie et al. (1941), and of thiouracil by Astwood (1943) ; and many subsequent studies have expanded these discoveries. Griesbach et al. (1941) showed that the goitrogenic action of these drugs was mediated through secondary stimulation of the anterior pituitary, arising from the interruption of thyroid-hormone secretion. The known antithyroid - drugs can be grouped into three main chemical types (Charipper and Gordon 1947) : (1) the thiourelene compounds, characterised by the thiocarbonamide grouping z N - CS - N <), which include thiourea, thiouracil, and ergothionene ; (2) the anilene derivatives, characterised by the aminobenzene grouping and including the sulphonamides, and aminobenzenes such as 4.4’ diaminodiphenylmethane and (3) the thiocyanates and the organic cyanides. Chemically, resorcin,

or

resorcinol,

a

dihydroxyphenol,

clinical studies ; to Mr. D. G. Arnott, B.sc., and to Mr. F. S. Stewart (Medical Research Council radiotherapeutic unit) for the isotope measurements ; to Miss P. Scarlett for the iodine estimations ; and to Mr. V. Wilmott for the photographs. We are also especially indebted to Dr. R. J. Harrison for bringing case 3 to our notice, and for his generous courtesy in transferring her to our care for a period of investigation. REFERENCES

Arnott, D. G., Emery, E. W., Fraser, R., Hobson, Q. J. G. (1949) Lancet, ii, 460. Astwood, E. B. (1943) J. Amer. med. Ass. 122, 78. Bissell, A., Hughes, A. M. (1945) Endocrinology, 37, 456. Charipper, H. A., Gordon, A. S. (1947) in Vitamins and Hormones; edited by R. S. Harris and K. V. Thimann. New York ; —

vol. v, p. 273.

Chesney, A. M., Clawson, T. A., Webster, B. (1928) Bull. Johns Hopk. Hosp. 43, 261. Doniach, I., Fraser, R. (1950) Lancet, May 6, p. 855. Entenman, C., Chaikoff, I. L., Reichert, F. L. (1942) Endocrinology, 30, 794. Griesbach, W. E., Kennedy, T. H., Purves, H. D. (1941) Brit. J.

exp. Path. 22, 249. Hercus, C. E., Purves, H. D. (1936) J. Hyg., Camb. 36, 182. Mackenzie, J. B., Mackenzie, C. G., McCollum, E. V. (1941) Science,

94, 518. Marine, D., Baumann, E. J., Spence, A. W., Cipra, A. (1932) Proc. Soc. exp. Biol., N.Y. 29, 772. Peters, J. P., Man, E. B. (1943) J. clin. Invest. 22, 707, 715, 721. Rawson, R. W., Hertz, S., Means, J. H. (1943) Ann. intern. Med. 19, 829. Vanderlaan, J. E., Vanderlaan, W. P. (1947) Endocrinology, 40, 403.

EFFECT OF RESORCINOL ON THE THYROID UPTAKE OF I131 IN RATS M.D. N.Z., F.R.C.P., D.P.M. M.D. Lond. From the Postgraduate Medical School of London

IN three elderly women with myxoedema and a goitre, Bull and Fraser (1950) found that the thyroid disorder was due to prolonged application of a resorcinol ointment to varicose ulcers. Radio-iodine uptake studies confirmed the suspicion that the resorcinol applied to these ulcers had an antithyroid action and suggested the need for further study of this antithyroid action. We report here preliminary results of some experiments on the effect of resorcinol on thyroid function in the rat.

OH

01,

METHODS

is not

clearly

allied to any of the former

groups, but some of its known chemical features may be relevant to its antithyroid action. Itt can be iodinated either by free iodine, or by iodides in the presence of an oxidising agent, to form tri-iodoresorcinol. Its formula somewhat resembles that of tyrosine, HO

0 CH2CHNH2.COOH, which

is believed to be

the precursor which the thyroid gland iodinates by some oxidising mechanism, in the presence of iodide, to form thyroxine and the thyroid hormone. The antithyroid action of resorcinol may be due to its competing in the thyroid gland with tyrosine for the iodinating mechanism ; or to some other toxic action. Further investigation is in progress on the biological action of resorcinol and allied substances. SUMMARY

In three cases myxoedema was associated with varicose ulcers to which resorcinol ointment had been applied. Further study showed that the thyroid glands of these patients were enlarged and hyperactive. On withdrawing resorcinol, the myxcedema subsided and thyroid function returned to normal. Resorcinol, when absorbed through a leg ulcer, is an

antithyroid agent. We wish to acknowledge an indebtedness to many colleagues for help with these studies : to Mr. Maurice R. Ewing and

Mr. Selwyn

RUSSELL FRASER

I. DONIACH

Taylor

for

biopsies ;

to Dr. I. Doniach for the

histological studies ; to Dr. Q. J. G. Hobson, aided by Dr. L. Phillips and Dr. M. Jones, for extensive assistance in the

Adult rats, weighing 150-250 g., mostly females of the hooded Lister strain, were used throughout. The

ability of the rats’ thyroids to take up iodine was by killing them 1, 11/2’ and 2 hr. after an intraperitoneal injection of 10 microcuries ([.C) J131 with 0’5 u.g. carrier potassium iodide, and counting the radioactivity in the alkaline digest of the dissected thyroid glands in a liquid counter (Veall 1948). For autoradiographs, rats were killed 2 hr. after an intraperitoneal injection of 18 {j!.C of I131. Drugs whose antithyroid effect was being tested’ were injected subcutaneously in 1 ml. of water, 10-30 min. before administration of Il3i, the injection sometimes being repeated 1 hr. later. The effect of these drugs was assessed either by measuring the reduction in the thyroid uptake from that found in the controls, or by making an autoradiograph instead of the digest. The drugs used were: 4-methyl-2-thiouracil, as a watery suspension of crystals containing at least 50 mg.. per ml.,, to ensure maximalantithyroid effect ; sodium thiocyanate, 50 mg. per ml. ; and resorcinol in graded doses or given in the drinking-water as a 2% solution. In the accompanying figure, the thyroid uptake of each rat is recorded simply as the actual number of counts per min. given by the thyroidal digest,* and the results are summarised. measured

,

RESULTS

Previous

weight)

or

injection with 1 mg. (5 mg. per kg. bodymore of resorcinol reduced the iodine uptake

* The results are presented by this method because of the- wide range of readings among the controls and the small number of rats used per The reader should compare the uptake of any rat only with that of the controls or others recorded in the same experiment. The ratio of uptake’ by treated rats to their own . controls is comparable in all

experiment.

experiments.

856

significantly different from that at the end of 2 hr. ; thus the addition of thiocyanate at 1 hr. before killing had evidently discharged some of the iodide ion which had been concentrated there despite the presence of resorcinol. Vanderlaan and Vanderlaan (1947) have reported similar results with propyl thiouracil and thiocyanate. From the figure (experiments 2 and 3) it will also be noted that when thiouracil is given in addition to resorcinol antithyroid action was not enhanced. With regard to the toxicity of resorcinol, 50 mg. doses never proved fatal, but the injected animals all showed Smaller doses a severe tremor for the first half-hour. had no overt toxic results. CONCLUSIONS

Preliminary

antithyroid action of thyroid uptake, shows it to be similar to that of methyl thiouracil in all the respects tested-namely, the maximal depression of thyroid uptake of iodine which can be induced, the abolition of organic binding as evidenced by autoradiography, and the enhancement of its antithyroid effect obtainable by the additional injection of thiocyanate but not of methyl thiouracil. We are indebted to Mr. D. G. Arnott, B.sc., for the isotope

resorcinol

on

assessment of the

rats, using Il3i to

measurements and Pelc, PH.D., for the

measure

help in the experiments, autoradiographs.

and to Mr. S. R.

REFERENCES

Bull, G. M., Fraser, R. (1950) Lancet, May 6, p. 851. Vanderlaan, J. E., Vanderlaan, W. P. (1947) Endocrinology, 40, 403. Veall, N. (1948) Brit. J. Radiol. 21, 347. Inhibiting effect of resorcinol on uptake of 1181 by rats’ thyroids, compared with that of methyl thiouracil and sodium thiocyanate. Each rat is represented by a horizontal bar whose length gives the counts The rats were killed 2 hr. per min, recorded from its digested thyroid. after injection of 10 fix 113’, except all rats in experiment 3, which were killed 1’/. hr. afterwards, and those shown as open bars in experiment 4, which

were

killed t hr. afterwards.

of that found in controls-an extent not exceeded with higher doses and comparable to the maximal reduction obtained with methyl thiouracil. Further experiments will be needed to establish the minimum dose required to produce the maximal antithyroid effect. A number of rats were given the resorcinol in two doses -the second, 1 hr. 10 min. before they were killed. As is shown in the figure, the results did not differ greatly from those produced by single doses. When the resorcinol was administered orally instead of parenterally, there was an indication in some animals of a smaller, but definite, antithyroid effect, which will be further studied. Comparison of the antithyroid action of resorcinol with that of other known drugs throws some light on its mode of action on the thyroid. The thyroid is known to concentrate iodide from the serum in at least two steps-first by concentrating the iodide in the gland, and then by organic binding of this iodide into protein, in which form most of the thyroid’s store is made. The first step is inhibited by thiocyanate and the second step by the thiouracils ; in each case this is the only known antithyroid effect of the drug. Autoradiographs of alcoholfixed paraffin-embedded thyroids show the presence of organically bound iodine only. Autoradiographs made after pretreatment with resorcinol, as after methyl thiouracil, failed to show any organically bound 1. The prevention of organic binding was further confirmed by finding that the antithyroid action of resorcinol could be further enhanced by injecting sodium thio- cyanate 1 hr. before killing ; and the antithyroid action of methyl thiouracil could be enhanced in exactly the same way (see figure, experiments 2 and 3). This addition of thiocyanate further reduced the concentration of p31 from 1/5 to 1/10 of that obtained with resorcinol or methyl thiouracil alone. In this connection, it should be noted from experiment 4 that the thyroid uptake in the presence of resorcinol at the end of 1 hr. is not to

1/5-1/9

SEROLOGICAL DIAGNOSIS OF HERPES SIMPLEX INFECTIONS MARGARET E. HAYWARD

*

B.Sc. Melb. From the

Department of Bacteriology, University of Liverpool

PRIMARY infection with herpes simplex virus occurs frequently in young children (Dodd et al. 1938, Burnet and Williams 1939). The primary infection may be symptomless (Anderson and Hamilton 1949) or there may be clinical manifestations varying from inconspicuous vesicular lesions about the mouth, with or without stomatitis, to more extensive eruptions on the skin of other parts of the body, especially in children or adults suffering from chronic eczema. The acute stomatitis (aphthous stomatitis) may be accompanied by constitutional upset (McNair Scott et al. 1941). Cases of herpetic meningo-encephalitis may also be commoner than the literature suggests. Infected individuals apparently carry the virus throughout life and, their sera contain antibodies to the virus. The diagnosis of herpetic infection may be confirmed or established by isolation of virus or by demonstrating an increase in antibody in the serum during the illness. Estimation of serum antibody has generally been made by testing the power of the serum to inhibit the action of the virus in susceptible animals or to prevent the development of lesions on the chorioallantois of developing chick embryos (neutralisation test). Such methods require several days for their performance and a sensitive in-vitro serological test would offer obvious advantages. Sera containing antibodies to herpes virus were shown by Bedson and Bland (1929) to fix complement in the presence of a herpetic antigen ; their technique when used in the examination of human sera (Brain 1932) did not give as high a proportion of positive reactions in adults as did the neutralisation test in the hands of other workers (Andrewes and Carmichael 1930, Burnet and Williams 1939). *

Holding the John W. Garrett International Bacteriology.

Fellowship

in