Formation of Adenomata in Hypophyses of Rats Subjected to both Subtotal Thyroidectomy and Administration of'311, and its Prevention by Feeding of Desiccated Thyroid1

w. E. GRIESBACH,2 J@ L. CHAIKOFF, C. W. NICHOLS, JR., AND ROBERT C. GOLDBERG@ Department of Physiology, University of California, Berkeley, California

SUMMARY The tumorigenic effect of subtotal thyroidectomy on the pituitary was studied in 212 Long-Evans female rats. Of the 133 pituitaries that contained adenomata after 2 years, 76 % were of the type. This finding confirms earlier work on the effect of long-term thyroxine deficiency. The feeding of desiccated reduced the @)ercentages of thyrotropic cell adeno mata from a mean of 60 to a mean of 33. Thyroid feeding reduced the percentages of all adenomata from a mean of 72 to a mean of 53. A single administration of 1 @ecof 1311did not increase the number of, or tendency towards, anaplastic changes in @)ituitary adenomata of subtotally thyroidectomized rats fed a stock diet. The same dose of 1311did not increase the incidence of pituitary adenomata iii unoperated animals fed either the stock diet or the stock diet supple mented with desiccated thyroid. Two rats that developed malignant thyroid car cinomata after receiving 1 @.icof131Jdid not show cell changes or adenomat.a in the pi tuitary. The absence of cytologic signs of thyroxine deficiency in the pituitary cells of these rats supports the view that irradiation per se might well have been the cause of the neoplasms found in their thyroid glands. The pituitary adenomata found in 124 unoperated rats, treated in the same way as the subtotally thyroidectomized groups with respect to ‘@‘Idosageand thyroid feed ing, closely resembled those found in the normal control group in number as well as in cell type.

It has been knowii for almost 2 decades that hyperpla.sia study of the TSH-producing cells in the pituitary, lend as well as benign and nialignant neopla.sms develop ill support to this interpretation. The literature dealing thyroid glands of Irlice and rats in which, for prolonged with this subject has been reviewed by Bielschowsky (2) periods, a state of thyroxine deficiency has been estab and Bielschowsky and Horning (3). lished by any one of the following means : the feeding of a A matter of some interest as well as practical importance low-iodine diet (1, 2) ; the administration of anti-thyroid arose in the case of experiments in which irradiation was substances (5, 15, 25) ; irradiation of the gland by 131J, applied to the rodents' thyroid gland, either alone or in astatine (211At), or X-rays (7, 12, 14, 19) ; and subtotal combination with chemical or surgical means, for inducing thyroidectomy (6, 14). There is good evidence for the the thyroxine deficiency. In most cases, especially in the belief that the neopla.st.ic changes should be attributed to early work with large doses of 131J(up to 875 j@c),the irra the hyperplasia of thyrotropic (TSH4)-producing diation had been sufficiently strong to destroy much or all cells in the glands of the animals suffer of the thyroid tissue (11, 12). In later experiments the ing from long-terni thyroxine deficiency. Assays of TSH 131J was given in a considerably reduced dose (25—40 Mc). contetits of the hypophysis and blood, as well as cytologic It was shown that hereby the number of experimentally induced malignant thyroid neoplasms was definitely higher 1 This work was supported by a contract from the United States Atomic Energy Commission (UCB-34P11-3). (22). It could further be seen that hyperplasia of the 2 Department of , Medical Research Council, thyroid epithelium surrounding the neoplasms was a con Dunedin, New Zealand. stant feature of these glands. It was assumed that this 3 Department of Medicine, Permanente Medical Group and was significant for the strong and permanent action of Kaiser Foundation Hospital, Oakland, California. thyrotropic hormone. No signs of radiation damage were 4 The following abbreviations are used: TSH, thyrotropic hormone; PAS, periodic acid-Schiff; PTA, phosphotungstic acid; found. The question whether ilradiation per se can induce AF, aldehyde fuchsin. thyroid tumors was discussed in another study in which Received for publication March 4, 1965; revised June 7, 1965. either both lobes or a single lobe of the thyroid gland had 1804

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TABLE 1 ADENOMATA IN PITUITARIES OF INTACT FEMALE RATS

PvruITARIEsGROUPTREATMENTNo. ADRNOMATATotal CLASSIFICATIONOP OF RATS ADENOMATACYTOLOGIC EXAMINED

(76%)INoneVI1 47WITH 21% 45Thyrotrophs3 (14%)Gonadotrophs2Chromophobes16 (60%)VIIDesiccated@c‘@‘Iinjected3410293 (30%)16 (70%)VIII1 thyroid in diet5723403 (13%)416 (82%)Total17171429@c1311plus desiccated thyroid in diet3317510314

(13%)10 (14%)52 (73%)

TABLE 2 ADENOMATA IN PITUITARIES OF SUBTOTALLY THYROIDECTOMIZED FEMALE RATS

PITUITARIES WITH CYTOLOGIC CLASSIFICATION OF ADENOMATA No. OF RATS ADENOMATA No. or Gaow' TREATMENT ADENOMATA r'ANAPLASTIC EXAMINED CHANGES IN: CLASSIFIED Total % Thyrotrophs Gonadotrophs Chromophobes

II Subtotal thyroidectomy only 67 42 63 36 (86%) 3 6 (14%) 45 8 (18%) III Subtotal thyroidectomy plus 49 40 82 33 (83%) 4 5 (13%) 42 10 (24%) 1 pc 1311injected IV Subtotal thyroidectomy, 1 @IC 60 32 53 22 (69%) 3 8 (25%) 33 5 (15%) 1311 injected plus desiccated thyroid fed V Subtotal thyroidectomy plus 36 19 53 10 (53%) 2 7 (37%) 19 2 (10%) desiccated thyroid fed

Total 212 133 63 101 (76%) 12 (9%) 26 (20%) 139 been irradiated (21). There, most of the carcinomata 1 and 2) received by i.p. injection 1 j@tCofcarrier-free 131J were found in rats in which both lobes had been irradiated, in 0.1 ml of normal saline. Twenty-four hr later the but 2 carcinomata also appeared in singly-irradiated lobes isthmus contained about 2 % of the radioactivity. and 1 in an opposite, shielded lobe. Hence, it could not One week after either the subtotal thyroidectomy or be decided whether thyroid carcinogenesis resulted from 1311 injection, feeding of the thyroid-supplemented diet prolonged TSH stimulation or was a direct consequence of was begun. The diet was prepared by adding desiccated the irradiation. In a more recent paper, Goldberg et al. thyroid powder (Lilly Thyroid, U.S.P., No. 58) to the (14) reported finding a papillary and a follicular carcinoma stock diet to yield a concentration of 250 nig/kg. It was in intact thyroid glands of rats that received but a single shown in a separate experiment that the uptake of ‘@‘Iby /hc of 131J The present report deals with the 383 pitui the thyroid glands of the rats fed this diet was almost com taries excised from the rats whose had been de pletely suppressed. scribed in this latter study (14). In these pituitaries, The rats were maintained for 2 years, and the survivors many adenomata were found; they are described in detail, were killed with ether. Those that failed to survive for particularly with regard to the hormonal conditions that the 2 years usually died of chronic respiratory disease, may have influenced their development. and autopsies were not performed on all of these animals. The thyroid glands of the rats of Groups I and VI-Vill MATERIALS AND METHODS were excised and weighed. In all other rats, the tracheas A total of 876 female, Long-Evans rats were randomly along with the paratracheal tissues were removed en bloc selected at 5-6 weeks of age, divided into 8 groups, and and fixed in 10 % neutral formalin. The pituitary glands treated as shown in Tables 1 and 2. After weaning, all were removed and fixed in sublimate-formol (9 : 1, v/v). rats were maintained on a nutritionally adequate diet These glands were sectioned at 2.5 and 5 @,and sections (Diablo Double-Check Labration) containing 3 @sgof from each were mounted on 4 slides, with equal distribution iodine/gm5 (20). onto each slide of the material cut at various depths of the Subtotal thyroidectomy was performed under light block. They were treated as follows : Slides 1 and 2 with ether anesthesia. Both lateral lobes of the thyroid were periodic acid-Schiff (PAS) stain and PAS stain in combi removed, leaving only the isthmus, which weighed about nation with Orange G-phosphotungstic acid (PTA), re 0. 1 mg. One week later, each rat of certain groups (Tables spectively ; Slide 3 with aldehyde fuchsin (AF) usually

5 We are indebted to Dr. G. La Roche for this determination. followed by Orange G-PTA, without previous oxidation

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TABLE 3 SUMMARY OF CYTOLOGIC FINDINGS IN THE PITUITARIES OF RATS WITH THYROID CARCINOMA

GroupTreatmentpituitaryIISubtotal of ratsTyreoftlurroidType of pituitary neoplasmClassification of cells in

thyroidectomyPapillaryNone3 cysts in chromophobic areas; few TSIF' foundIISubtotal and LH cells; acidophils not thyroidectomyPapillary(a) Large adenoma; (b) small TSH and “T―-granulated cells; few anaplastic adenoma(a) acidophils; (b) atypical cells, probably basophilsIVSubtotal thyroidectomy + 1 pc cells; LH cells and groups of presentVIInjection1311 injection + addition of acidophils desiccated thyroid to dietPapillaryNone“T―-granulated @ of 1 1311FollicularNoneTSH cells, LII cells, acidophils present in quantitiesVIIIInjection normal of 1 sc 13h1+ addition cells, LH cells present; acidophils in of desiccated thyroid to dietPapillaryNoneTSH creased in numbers

a TSH, thyrotropic hormone; LH, luteinizing hormone.

with permanganate ; and Slide 4 with the rapid Mallory The number of gonadotroph adenomata was not changed stain of Churg and Prado (4). The last is well suited for by thyroid feeding, but that of chromophobe adenomata counterstaining AF-stained tissues. was increased—29 %, as compared to 12 % in rats fed the stock diet. RESULTS GENERAL REMARKS EFFECTS OF 131J ADMINIsTit@TIoN Considerable numbers of adenomata were found in the In Groups VI and VIII (unoperated rats, Table 1), in anterior hypophyses of both unoperated (Table 1) and which the majority of adenomata were of the chromophobe subtotally thyroidectonlized (Table 2) rats. Such pitui cell type, no significant effect of the 1311injection was de tary neoplasms were seen in 71, or 42 %, of the unoperated tected. Among the subtotally thyroidectomized rats, animals and in 133, or 63 %, of the operated ones. A cyto Groups III and IV, comprising 109 animals (Table 2), re logic examination revealed, however, that the adenomata ceived 131J,whereas Groups II and V (103 animals) re were constituted of quite different cell types in these 2 ceived no 1311 Groups IV and V (96 rats) were fed the major groups of rats. In the unoperated rats, the chro desiccated thyroid-containing diet. The incidence of mophobe cell type of adenoma predominated ; its incidence thyrotropic cell adenomat.a was not significantly altered in here was 29 %, as compared with 12 % in the operated rats. Group III by the ‘@‘Iadministration as compared with On the other hand, nearly half of the operated rats—101, Group II, which received no ‘@‘I.Ofall adenomata found or 48 %—had adenomata composed principally of thyro in Group III, 83 % were thyrotropic cell adenomata. The trophs; the corresponding figure for the unoperated rat corresponding figure for Group II was 86 %. In the was 9, or 5 %. Thus, subtotal thyroidectomy induced an thyroid-fed rats, the higher percentage (69 %) of all adeno almost 10-fold inciea.se in thyrotroph adenomata and at mata belonged to Group IV (‘@‘I-injected).Group V the same time reduced the incidence of chromophobe (‘@‘Inotinjected) contained the lower percentage of 53 %. adenomata 2.5-fold. There was no significant difference Anapla.sia was found more frequently in the adenomata of between the numbers of gonadotroph adenomata in un the rats fed the stock diet than in those of rats fed the operated and operated groups (see “Histology―). desiccated thyroid-containing diet—21 % versus 13 % (Table 2). EFFECT OF Tin-R0ID FEEDING ON iNCIDENCE The 2 unoperated rats in which Goldberg et at. (14) found OF ADENOMATA malignant thyroid neoplasms following the administration No effect of thyroid feeding on the general pituitary of 1 @cof 131Jdid not show pituitary adenomata or any cell picture of the unoperated rats was detected. The deviation from the normal cell picture in their anterior presence of a large number of acidophil cells was obvious pituitary glands (Table 3). and was to be expected in the anterior pituitary of normal rats fed the desiccated thyroid-containing diet continu HISTOLOGY OF NEOPLASMS Fou@ IN ANTERIOR ously. PITUITARY GLANDS The number of acidophil cells in the pituitary glands of Neoplasms were found in the pituitaries of all 8 groups the subtotally thyroidectomized rats fed the normal diet of rats. These neoplasms contained primarily 1 type of was quite low. The addition of desiccated thyroid to the cell, and each neopla.sm was therefore classified according diet of the rats changed the picture to normal. to its main cell type. Difficulties in classification arose in The number of thyrotroph adenomata in Groups II and a few cases because of anapla.stic areas in some of the neo III (fed the stock diet) was 69, or 60 %. Under the in pla.sms. fluence of thyroid feeding, the number of thyrotroph adenomata.—These were found in 30% adenomata in Groups IV and V fell to 32, or 33 %. of the anterior pituitaries of all unoperated rats and in 12 %

Downloaded from cancerres.aacrjournals.org on September 24, 2021. © 1965 American Association for Cancer Research. GRIESBACH et al.—Hypophyseal Adenoma after Thyroidectomy and 131J 1807 of all thyroidectomized rats at the end of 2 years. They that “T―-granulatedcells can form adenomata. In the were composed of small cells that did not contain stain present study we found, in nearly 50 % of adenomata, able granules. In many neopla.sms of this type, the cells “T―-granulatedcell nodules adjacent to typical thyrotroph had a follicular arrangement. The follicles were filled adenomata in a single . The fact that the with blood. Grossly visible hemorrhages were often “T―granulesseen here always stained with AF helped found; these, in combination with rapid growth (mitoses), avoid confusion with the gonadotrophs (Fig. 13 ; see also compressed the surrounding areas of otherwise intact Ref. 24). pituitary tissue. Almost regularly, macrophages contain Fully hyalinized cell areas were found in 14 % of the ing hemosiderin (clasmatocytes) were seen in the chromo pituitaries with thyrotroph adenomata. Such hyalinized phobe adenomata, and these macrophages were stained cells resembled “thyroidectomy― cells and sometimes with PAS. So typical were the hemosiderin-containing formed large parts of the neoplasms. Even mitoses were cells that this type of adenoma was easily recognized in found among them (Fig. 9; see Ref. 18). unstained sections by the presence of brown pigment (27). Gonadotroph adenomata.—The number of gonadotroph Thyrotroph and thyroidectomy cell (“T―-granulatedcell) adenomata was small and was not affected by subtotal adenomaLa.—Neoplasms composed of thyrotrophs were thyroidectomy. The cell type was the pale central van found in 9 pituitaries of the unoperated rats (5 %) and in ety (luteinizing hormone) described by Purves and Gnies 101 pituitaries of the thyroidectomized groups (48 %). In bach (17, 23). These cells are round or oval and have the former, the neoplasms were small and never anapla.stic. dark-red-stained Golgi areas near the nuclei, surrounded The thyrotroph cells, which were multangular and irregu by pale cytoplasm (after PAS). Rapidly growing neo lar, sometimes bizarre, in shape, stained well with alde pla.sms of this type with many mitoses and compression hyde fuchsin; the sections had not been previously oxidized of the neighboring area were noted (Fig. 16). in contrast by permanganate (Figs. 1—3,11). The intensity of stain to the thyrotroph adenoma, the gonadotroph adenoma ing was not constant throughout the adenomata (Fig. always preserved its acinar structure and manifested 10), probably because the degree of granulation in the strongly PAS-positive vascular n@embranes. This helped cells varied. to differentiate the 2 adenoma types, even at low mag The pleomorphic cells of partially anaplastic neoplasms nification. often contained aldehyde fuchsin-positive granules (Figs. DISCUSSiON 7, 8). Such neoplasms occasionally contained large hy pertrophic cells with mitoses of unusual size (Fig. 17). GENERAL CONSIDERATIONS The type of thyrotroph adenoma most frequently en This paper deals with the cytology of the anterior hy countered, however, contained relatively uniform, tightly pophyses of the rats used in the experiments of Goldberg packed cells that stained intensely with aldehyde fuchsin et al. (14). A large number of pituitary adenomata were and had vesicular, round or oval nuclei with 1 nucleolus found in these rats and were cla.s.sified according to their (Figs. 4, 5, 14). morphologic appearance as thyrotropic, gonadotropic, or The adenomata varied greatly in size and shape. Usu chromophobe. Their size was small, measuring 1—2mm ally they were multiple, and as many as 6 discrete foci in diameter, and they could not be separated from the have been noted in a single gland. Since these would surrounding pituitary tissue even when their presence not be expected to grow at the same rate or to possess was known before autopsy. This fact prevented an assay identical degrees of neoplastic change, it is not surprising of the neopla.stic tissue for its hormone content by biologic that quite different structures were seen in a single pitui means. The presence of thyrotropic cells in the ade tary or even in a single adenoma (Figs. 5-8). The pres nomata therefore had to be based on their characteristic ence in such growths of aldehyde fuchsin stained cells multangular form and their specific stainability with having the angular shape characteristic of thyrotrophs aldehyde fuchsin without previous oxidation of the section. simplified the differential diagnosis of such neoplastic Goldberg et at. (14), 2 years after starting the expeni alterations (Figs. 12, 15, 18). The area in the anterior ments, found, in addition to many adenomata, 5 carci lobe with the highest incidence of thyrotroph adenomata nomata in the thyroid glands of their rats. One papillary was the posterior edge near the . and 1 follicular carcinoma developed in the intact thyroids The pituitaries of the subtotally thyroidectomized rats of rats that received only 1 @.tcof131J,and it was believed contained a large number of hyalinized basophil cells, the possible that these neoplasms were induced solely by the so-called thyroidectomy cells, which are known to be radiation. A single papillary carcinoma developed in a thyrotrophs that were transformed during the state of rat that had been subjected to subtotal thyroidectomy, thryoxine deficiency. According to Purves and Griesbach given an injection of 1 @c131J,and fed the desiccated (24), such cells, found in the pituitaries of rats in which thyroid-containing diet. The question arose whether the thyroxine deficiency has been established for at least 2 tumor-producing mechanism could be deduced from a weeks, contain coarse PAS-stainable granules (“T―gran study of the pituitary glands (Table 3). tiles) that differ from normal thyrotrophic granules in It is now widely acknowledged that enhanced and pro being insoluble in water and not implicated apparently in longed thyrotropin secretion from the pituitary gland thyrotrophic hormone production. ‘‘T―-granulesmay may provoke hyperplasia of thyroid cells, adenoma forma also be stained by intense aldehyde fuchsin treatment tion in the thyroid gland, and provided a state of thyroxine (24), especially after preoxidation with permanganate. deficiency is established for a prolonged period, even Recently, it has been shown by Doniach and Williams (6) carcinogenesis of the thyroid gland (1, 2, 6, 25). In

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creased thyrotropin secretion is manifested in the pituitary Bielschowsky (2) and Axelrad and Leblond (1) showed by greater numbers of thyrotropin-secreting cells (thyro in rats that a diet almost free of iodine could in the course trophs) and by the appearance of thyroidectomy cells. of time lead to adenoma formation in the thyroid gland It would, therefore, have been of interest if this had hap and the pituitary. These tumors were prevented from pened in the pituitaries of the 2 rats bearing carcinomata developing by the feeding of about 22 sg of KI per day. in their otherwise intact thyroid glands. This was not It is also well known that an inadequate supply of thy the case, however. The dose of 1311administered was too roxine following the administration of anti-thyroid sub slnall to have been destructive to the rats' thyroid glands, stances or subtotal thyroidectomy may cause neoplastic and this accounts for the absence of thyrotroph hyper reactions in the thyroid and pituitary glands of rats (3, 6, plasia and adenoma formation in their hypophyses. We 16). This is confirmed again here in the subtotally thy found no evidence that the injected 131J increased the roidectomized rats. It is doubtful that complete surgical effect of subtotal thyroidectomy on the pituitaries (see thyroidectomy leads to the formation of thyrotropic tu Groups II and III). The numbers of pituitary adenornata mors in the pituitary. Purves and Griesbach (unpub in these groups of operated rats, regardless of whether the lished observation) did not find that type of pituitary thyroid glands were irradiated, were not significantly dii neoplasms in rats after complete surgical thyroidectomy. ferent. We therefore have no reason to believe that the The experiences of Goldberg and Chaikoff (11, 12) and administered 131J had induced neoplastic changes in the Furth and his co-workers (7—10),as well as the recent pituitary cells. report on the action of astatine-211 (28), leave no doubt that after the destruction of the thyroid by radiation, CONCERNING THE MECHANISM OF PITUITARY TUMOR INDUCTION thyrotropic neoplasms are not formed in the pituitaries of rats. It seems possible that the rat hypophysis needs a Old rats of either sex have been shown to contain a very small amount of thyroxine to form neoplasms. This large number of spontaneous pituitary adenomata (27). would be produced by the thyroid-rest., which remains in These vary from microscopic to grossly visible tumors, the animal after the subtotal thyroidectomy applied in and they probably arise because of hormonal changes due this series of experiments. to aging. Chromophobe adenomata were found in 30 % Between 1950 and 1952, Goldberg el al. (1 1—13)dealt of the pituitanies of the unoperated rats in the present with the effects of ‘@‘I(indoses from 18 @cto 875 tic) on study. In another paper for which the same rat strain the structure and viability of the thyroid and pituitary (Long-Evans)wasused,VanDykeet al. founda similar cells of the rat. They showed that (a) a dose of 18 @icof incidence (26). Wolfe et al. (27) reported an occurrence 131J produced no demonstrable cytologic or functional of 29 % and 68 % of pituitary tumors in Vanderbilt and changes in either gland; (b) 300 @cof 131J caused mild Wistar rats, respectively, and Gniesbach and Purves (17), chronic inflammation and fibrous proliferation in the using a Wistar strain, found that of a total of 31 % ade thyroid, as well as a loss of acidophils and an increase of nomata, 23 % were of the chromophobe type. basophils in the pituitary ; (c) between 5 and 8 months Cramer and Horning (cited in Ref. 3) were the first to after the latter injection, both glands were similar to nor produce neol)lastic lesions in the rat pituitary experi ma! controls. With doses of 525-875 @cof1@1J,thedamage mentally by the administration of estrogen. These neo to the thyroid gland was much greater. Although 525 @tc plasms consisted of chromophobe cells and manifested a did not destroy the thyroid cells entirely, “atypical―epi strong tendency to hemorrhage ; they thus resembled the thelial cells with little follicular organization and scarce many chromophobe tumors reported in the present study. colloid appeared. After 6-8 months, atypical cells in Deficiency of sex , induced by gonadectomy in greater numbers and hypertrophic epithelium with follicu mice and some strains of rats, may also cause the develop lan organization were found. The almost complete de ment of chromophobe cum acidophil and of gonadotroph granulation of the pituitary acidophils proved that thy cell adenomata. Griesbach and Purves (17) reported roxine production in the damaged thyroids was quite @ that rats with such neoplasms secrete milk and that this inadequate (11). A dose of 875 @cof destroyed the is observed occasionally even in males. thyroid cells almost completely in 72 hr, and after 6 and

FIG. 1.—Medium-sized adenoma (0.9 x 0.8 mm) situated at caudal edge of anterior lobe. Individual cells show varied in tensity of staining. Group II, AF. X 90. FIG. 2.—Higher magnification of Fig. 1, showing irregular cell shape and variety of content of AF-stained granula. Group II, AF. X400. FIG. 3.—TSH cell adenoma covering nearly half of the anterior lobe and reaching far onto the rostral edge towards portal vessels. Group II, AF. x 90. FIG. 4.—The adenoma seen is one of several in this pituitary, and its cells are similar to typical TSH cells. Group III, AF. x 400. FIG. 5.—This and Figs. 6—8show the variety of cells in a single adenoma. Here are typical TSH cells with strong AF staining. Group II, AF. x 400. FIG. 6.—Area of “T―-granulated cells, some hyalinized. Group II, AF. X 900.

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Downloaded from cancerres.aacrjournals.org on September 24, 2021. © 1965 American Association for Cancer Research. Fio. 7, 8.—Thesame tumor shows more atypical cells stained with AF. Group II, AF. X 400. FIG. 9.—Adenoma with area of hyalinized thyroidectomy cells. Mitoses near center. Group III, PAS. X 400. FIG. 10.—TSH cell adenoma. Generally small cells varying greatly in shape and uptake of AF. Group III, AF. X 400. FIG. 11.—TSH cell adenoma showing the “stretched out― appearance not infrequently seen. Group III, AF. X 150. FIG. 12.—This pituitary contains adenomata, some with “T― granules and others, like the one depicted, with a tendency towards anaplasia. Group III, AF. X 400.

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Downloaded from cancerres.aacrjournals.org on September 24, 2021. © 1965 American Association for Cancer Research. FIG. 13.—Higher magnification of “T―-granulated cells giving a good picture of the coarse granules. Group III, PAS. X 900. FIG. 14.—Very large adenoma with uniformly small cells. Group IV, AF. X 400. FIG. 15.—Large adenoma showing unusual arrangement of the TSH cells. Group III, PAS. X 400. FIG. 16.—PAS-positive, AF-negative adenoma of “palecells― with intensely PAS-stained Golgi bodies, unoperated, 1311treated. Group VI, PAS. x 900. FIG. 17.—Adenoma with very large AF-positive and PAS-posi tive anaplastic cells, one showing a large mitotic figure. Group IV,PAS. X900. Fio. 18.—Anaplastic part of otherwise typical AF-positive TSH cell adenoma. The cells seen are not densely granulated. Golgi rings visible. Group III, PAS. X 900.

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8 months no thyroid cells could be found. The pituitaries, unoperated rats is considered to prove that no thyroxine 6—8months after the injection of 525—875 @.icof ‘@‘I,deficiency was present in these animals. The finding of 2 resembled those found after total thyroidectomy but were malignant thyroid neoplasms in rats treated with 1 g@cof restored to an approximately normal cytologic appearance ‘@‘I(GroupsVI and VIII) and showing no sign of pituitary by daily administration of 10 @tgof DL-thyroxine for 1 thyrotropic cell stimulation lends support to the view month. that irradiation per se can be an exciting cause of carcino Attention was drawn to the production of pituitary genesis in the thyroid gland of the rat. tumors in mice by thyroid-destroying doses of ‘@‘Iatabout the same time by Gorbman (15) and by Furth and Burnett REFERENCES (9). The pituitary tumors produced by these workers 1. Axeirad, A. A., and Leblond, C. P. Induction of Thyroid were of unusual size and could be transplanted. In the Tumors in Rats by a Low Iodine Diet. Cancer, 8: 339—67, earlier experiments, the hormone content of such tumors 1955. was mainly thyrotropic, but in later experiments adreno 2. Bielschowsky, F. Neoplasia and Internal Environment. Brit. J. Cancer, 9: 80—116,1955. tropic, mammotropic, somatotropic, and mixed tumors 3. Bielschowsky, F., and Horning, E. S. Aspects of Endocrine were also discovered (7—10). These were rich sources of Carcinogenesis. Brit. Med. Bull., 14: 106—15,1958. hormones. In the blood serum of mice with large tumors, 4. Churg, J., and Prado, A. A Rapid Mallory Trichrome Stain the concentration of thyrotropin was approximately 2000 (Chromotrope-Aniline Blue). Arch. Pathol., 6@:502-6, 1956. times the normal level. A number of publications by 5. Doniach, I. Effect of Radioactive Iodine Alone and in Combi nation with Methylthiouracil upon Tumor Production in the Furth and his associates on this subject have appeared (7, Rat's Thyroid Gland. Brit. J. Cancer, 7: 181—202,1953. 8). Halmi and Gude have given an excellent description 6. Doniach, I., and Williams, E. D. Development of Thyroid of the cytology of tumors induced by radiothyroidectomy and Pituitary Tumours in the Rat Two Years after Partial Thyroidectomy. Ibid.,16:222—31,1962. (18). 7. Furth, J. Morphologic Changes Associated with Thyrotrophin A recent paper (28) on the induction of pituitary tumors Secreting Tumors. Am. J. Pathol., 30: 421-63, 1954. in rats with astatine (211At) is interesting in this context. 8. . Experimental Pituitary Tumors. Recent Progr. Hor Although, as Hamilton et al. showed earlier (19), 2@At, mone Res., 11: 221—55,1955. 0.3 @&cpergm of body weight, destroys the thyroid gland 9. Furth, J., and Burnett, W. T., Jr. Hormone-Secreting Trans plantable Neoplasms of the Pituitary Induced by lIst. Proc. of the rat, no TSH-pituitary tumors were found in spite Soc. Exptl. Biol. Med., 78: 222—24,1951. of ample signs of thyroxine deficiency (thyrotroph hyper 10. Furth, J., and Clifton, H. Experimental Pituitary Tumors. plasia) in the pituitary. The authors state that “radio Ciba Found. Collog. Endocrinol., 12: 3—21,1958. thyroidectomy (in contrast to mice) does not elicit thyro 11. Goldberg, R. C., and Chaikoff, I. L. The Cytological Changes tropic pituitary tumors in rats.― that Occur in the Anterior Pituitary Glands of Rats Injected with Various Doses of J1@1and Their Significance in the Esti mation of Thyroid Function. Endocrinology, 46: 91—104,1950. THE PRESENT EXPERIMENT WITH 1 @cOF 1311 12. . On the Nature of the Hypertrophied Pituitary Gland The thyroid glands of the 3 groups of unoperated rats Induced in the Mouse by J131Injections, and the Mechanism of Its Development. Ibid., 48: 1—5,1951. (VI—Vill) described by Goldberg et al. (14) showed a 13. Goldberg, R. C., Chaikoff, I. L., Lindsay, S., and Feller, D. D. histologic pattern similar to that of their control group Histopathological Changes Induced in the Normal Thyroid (I). The suppression of thyroid activity in Groups VII and Other Tissues of the Rat by Internal Radiation with and VIII by feeding the thyroid-containing diet was to be Various Doses of Radioactive Iodine. Ibid., 48: 72—90,1950. expected. In all 4 groups, including the control Group I, 14. Goldberg, R. C., Lindsay, S., Nichols, C. W., Jr., and Chaikoff, I. L. Induction of Neoplasms in Thyroid Glands of Rats by a certain number of alveolar or lobular thyroid carcinomas Subtotal Thyroidectomy and by the Injection of One Micro were found (24—36%), as previously described in normal curie of J131 Cancer Res., 24: 35—43, 1964. Long-Evans rats (14, 20, 21). However, 1 papillary and 15. Gorbman, A. Tumorous Growth in the Pituitary and Trachea 1 follicular carcinoma developed in the otherwise intact Following Radiotoxic Dosages of I―. Proc. Soc. Exptl. Biol. thyroid glands of rats that received only 1 jsc of ‘@‘I. Med., 71: 237—40,1949. 16. Griesbach, W., Kennedy, T. H., and Purves, H. D. Studies These malignant neoplasms were possibly induced by the on Experimental Goitre. VI. Thyroid Adenomata in Rats 131J irradiation. A single papillary carcinoma was found on Brassica Seed Diet. Brit. J. Exptl. Pathol., 26: 18—24,1945. in a subtotally thyroidectomized rat (Group IV) that had 17. Griesbach, W. E., and Purves, H. I). Basophil Adenomata in been given 1 ;Lcof 1311inaddition to the thyroid-containing the Rat Hypophysis after Gonadectomy. Brit. J. Cancer, diet. This neoplasm could have been the result of either 14: 49—59,1960. 18. Halmi, N. S., and Gude, H. D. The Morphogenesis of Pitui prolonged thyrotropic hormone stimulation or 131Jirradia tary Tumors Induced by Radiothyroidectomy in the Mouse tion (14). and the Effects of Their Transplantation on the Pituitary In the present paper, possible cytologic changes in the Body of the Host. Am. J. Pathol., 30: 403—19,1954. pituitanies have been chosen as indicators of thyroxine 19. Hamilton, J. G., Durbin, P. W., and Parrott, M. W. The deficiency caused by inadequacy of thyroid function. Accumulation and Destructive Action of Astatine-211 (ekaio Subtotal thyroidectomy in all instances provoked the dine) in the Thyroid Gland of Rats and Monkeys. J. Clin. appearance of such cytologic changes, but it was impossible Endocrinol. Metab., 14: 1161—78,1954. 20. La Roche, G., Carpenter, D., and Coxworth, A. Isolation and to decide whether the changes had been aggravated by the Estimation of Serum Organically-Bound Iodine. II. Semi administration of 1311 (the number of thyrotropic cell Annual Report, Biology and Medicine, Donner Laboratory adenomata in Groups II and III were not significantly and Donner Pavilion, Lawrence Radiation Laboratory, UCRL different). On the other hand (Table 3), the absence of 11387,1964. thyrotroph hyperplasia in the pituitaries of the irradiated 21. Lindsay, S., Sheline, G. E., Potter, G. D., and Chaikoff, I. L.

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Induction of Neoplasms in the Thyroid Gland of The Rat by 25. Purves, H. D., Griesbach, W. E., and Kennedy, T. H. Studies X-Irradiation of the Gland. Cancer Res., @1:9—16,1961. in Experimental Goitre: Malignant Change in a Transplant 22. Potter, G. D., Lindsay, S., and Chaikoff, I. L. Induction of able Rat Thyroid Tumour. Brit. J. Cancer, 5: 301—10,1951. Neoplasms in Rat Thyroid Glands by Low Doses of Radio 26. Van Dyke, D. C., Simpson, M. E., Koneff, A. A., and Tobias, iodine. Arch. Pathol., 69: 257—69,1960. C. A. Long Term Effects of Deuteron Irradiation of the Rat 23. Purves, H. D. Morphology of the Hypophysis Related to Its Pituitary. Endocrinology, 64: 240—57,1957. Function. In: W. C. Young (ed.), Sex and Internal Secretion, 27. Wolfe, J. M., Bryan, W. R., and Wright, A. W. Histologic Vol. I, pp. 161—239.Baltimore:Williams & Wilkins Company, Observations on the Anterior Pituitaries of Old Rats with Particular Reference to the Spontaneous Appearance of Pi 1961. tuitary Adenomata. Am. J. Cancer, 34: 352—72, 1938. 24. Purves, H. D., and Griesbach, W. E. Changes in the Basophil 28. Yokoro, K., Kunii, A., Furth, J., and Durbin, P. Tumor Cells of the Rat Pituitary after Thyroidectomy. J. Induction with Astatine-211 in Rats. Characterization of Endocrinol., 13: 365—75,1956. Pituitary Tumors. Cancer Res., @4:683—88,1964.

Downloaded from cancerres.aacrjournals.org on September 24, 2021. © 1965 American Association for Cancer Research. Formation of Adenomata in Hypophyses of Rats Subjected to both Subtotal Thyroidectomy and Administration of 131I, and its Prevention by Feeding of Desiccated Thyroid

W. E. Griesbach, I. L. Chaikoff, C. W. Nichols, Jr., et al.

Cancer Res 1965;25:1804-1816.

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