Experimental-Histological Studies on the Changes in the Pituitary of the Mouse Following Administration of Anterior Lobe Extract (Praehormon)
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182 EXPERIMENTAL-HISTOLOGICAL STUDIES ON THE CHANGES IN THE PITUITARY OF THE MOUSE FOLLOWING ADMINISTRATION OF ANTERIOR LOBE EXTRACT (PRAEHORMON) TATsuo Aor Department of Anatomy, Nagoya University School of Medicine ( Director : Prof. Kazumaro Yam ada) In spite of extensive developments in hormone-therapy in recent years, it seems very difficult to determine the correct therapeutical dose of anterior pitui tary hormone for all indications. It can be assumed, moreover, that both ex cessive and insufficient administrations have been made frequently in the appli cation of this hormone. Consequently, it is conceivable that the hormone-balance of the body receiving such hormone treatment will be more or less affected by such undesirable administrations, and that such hormone-unbalance may result in significant functional alterations in certain endocrine glands. Therefore, it will be of high significance to investigate the effectiveness of this hormone which has an action on the hypophysis itself. For the purpose of clarifying the functional state of the hypophysis in cases receiving this hormone a study of histological changes in the pituitary of mouse injected with an anterior lobe extract was undertaken. At present, there are several reports concerning the problem mentioned above, in mice,8 > rats4 >5 > and guinea-pigs."> These reports, however, do not contain details sufficient for an understanding of the secretory activity of the pituitary. The purpose of the present paper is to serve as an introduction to further information on this problem. MATERIALS AND METHODS Seventy-seven mature male mice were subjected daily to subcutaneous in jections of an anterior lobe extract (Praehormon) for one to twenty-eight days. Half of them were injected with 0.1 rat unit of Praehormon per day and the other with 1.0 rat unit. All animals were killed on the day following the last treatment and their pituitaries were removed. In the present study, Zenker's, Reily's, Kolster's, Regaud's and Ciaccio's fluids were employed as fixatives. After fixation the pituitaries were dehydrated in alcohol and embedded in paraffin by routine procedures. Materials were sectioned at 4 or 6 micra serially and were stained chiefly with Hansen's hematoxylin and eosin and with Heidenhain's iron hematoxylin. In some sections, Gomori's rapid one step trichrome stain 7> and Heidenhain's azan stain were also employed. Received for publication July 4, 1956. MOUSE HYPOPHYSIS FOLLOWING PRAEHORMON ADMINISTRATION 183 RESULTS AND DISCUSSION A. Proper capsule The proper capsule of the pituitary showed an almost similar appearance as those of normal mice. B. Anterior lobe The arrangement of the parenchymal and border cells and the interstitial connective tissues did not appear to show any alterations, when compared with the normal aspect. 1) Blood capillary In the peripheral blood vessels, sinusoidal enlargement and hyperaemia were frequently observed and indicated gradual increase with increase in number of administrations (Figs. 1 and 4). These observations agree with those of Haterius and Charipper,s) while Baniecki 4 ) and Collip, Selye and Thomson 'l reported that intense hyperaemia or bleeding is observed in the anterior pituitary of the rat treated with an anterior lobe extract. These different results are due probably to the dose of anterior lobe extract used. Further, it is probably justifiable to consider that these changes in the blood capillaries occur as an autoregulation phenomenon resulting from a functional alteration of the anterior pituitary due to the treatment. Consequently I can not support the results of Franck 6) who did not recognize an hyperaemia with various doses of the extract. 2) Chromophobe cell Chromophobe cells increased in number with progress of the experiment, in general. Typical chromophobe cells (Fig. 1) showed a tendency to reduction in number, while the number of chromophobe cells containing dark or irregular shaped nuclei (Fig. 1) increased in proportion to the succession of experiment. The chromophobe cell possessing a slightly dark nucleus and scanty light cytoplasm (Fig. 3) showed, even though not so marked, an increase in number with progress of the experiment. This chromophobe cell has mainly a round or oval nucleus which is closely similar to that of an eosinophile cell, and can be accepted to be a mutually transitional form between the chromophobe and eosinophile cells. In addition, chromophobe cell containing a light vesicular nucleus and scanty light cytoplasm and showing a distinct cell boundary (Fig. 2) was observed somewhat abundantly than in the normal. The chromophobe cell containing a nucleus in which nodular or droplet-like chromatin granules are irregularly distributed (Fig. 3 and 7) showed some in crease with continuation of treatment. These nuclei were generally ovoid, elon gated or rarely irregular-shaped, and sometimes two of them were located side by side. These nuclei will be designated as "droplet-nucleus" for descriptive purposes. In regard to chromophobe cells, Haterius and Charipper 5l described that definite variation was not observed, but the present results did not agree with 184 T. AOI their data. The transformation of nuclei described by Baniecki 4l was also ob served in the present experiment. Collip, Selye and Thomson 5l reported the appearance of extremely large cells containing eccentrically situated nuclei or large vacuoles in the cytoplasm, and Baniecki pointed out vacuolization of nuclei and an increase in amount of chromatin. In the present observations, however, these changes could not be recognized. On the other hand, an increase in num ber of chromophobe cells was observed in the present experiment as in Franck's data, especially in animals injected with 0.1 R.U. per day of Praehormon. 3) Basophile cell It is possible to classify basophile cells into three types, viz. typical basophile, B-1 and B-2 cells. The typical basophile cell: The cell contains a large nucleus showing a delicate chromatin network and abundant cytoplasm staining basophilic or am phophilic (Figs. 1 and 3). The cell showed gradual decrease in number with progress of the experiment, and especially in the middle stage the decrease was marked. On the contrary there appeared an increase in number of the cell towards the end. The B-1 cell: The cell contains a relatively large, dark nucleus with a delicate chromatin network and with comparatively distinct karyosomes, and somewhat abundant cytoplasm indicating feeble stainability (Fig. 3 and 5). The number of this cell at the early stage of experiment showed an increase in number. Later, with progress in administration the number of this cell de creased gradually accompanied by a temporary increase. The B·2 cell: This cell contains a large, light nucleus denoting somewhat coarse chromatin network and little cytoplasm which is difficult to stain with various dyes (Fig. 3). A slight increase in this cell was found only in the middle stage. With a decrease in number of typical basophile cell, there was an increase in number of B-1 cell and a slight increase of B-2 cell. The marked decrease in typical basophile cell was followed by an increase of B-2 cell, and later by B-1 cell. Toward the end of this experiment, increase of typical basophile cell and decrease of B-1 and B-2 cells were observed. From these findings, it can be suggested that the typical basophile and chromophobe cells can pass mutually through the B-1 and B-2 cells. The decrease in number of typical basophile cell observed in the present in vestigation agrees with the results of Franck who found a decrease in number of basophile cell in his shorter term experiment. However Franck, so also Haterius and Charipper and Baniecki, found no changes in basophile cells in his longer term experiment. In the present data, there were also some differences in the tendency to decrease in number of basophile cell according to the dose of Praehormon, and this will depend partly on a decline in biological response of an individual or partly on the occurrence of an autoregulatory function of the anterior lobe. From this, it may be proper to consider that, under certain circumstances, the typical basophile cell can show almost the same appearance as that in normal animals. MOUSE HYPOPHYSIS FOLLOWING PRAEHORMON ADMINISTRATION 185 Collip, Selye and Thomson observed basophile cell with a nucleus situated eccentrically in the cytoplasm and extremely large cell containing large vacuoles in the cytoplasm. These cells, however, were not found in the present obser vations. Franck found an increase in number of small basophile cell and of basophile cell containing few granules in the cytoplasm in his shorter term ex periment. It is probable that these cells will correspond respectively to my B-2 and B-1 cell, and the appearance of these cells agrees with that in the present experiment. 4) EosinoPhile cell The typical eosinophile cell containing a round or oval, light vesicular nucleus and somewhat coarse, acidophilic granules in the cytoplasm (Fig. 2) showed gradual decrease in number with increase in number of administration. On the contrary, there could be observed a gradual increase in number of cells containing irregularly shaped (Fig. 4), dark (Fig. 2), metachromatic (Figs. 4 and 7) or pyknotic nucleus (Figs. 4 and 7). Mitotic figures of eosinophile cells were more abundant than in normal (Fig. 3). Eosinophile cell containing the "droplet-nucleus" mentioned above and cyto plasm which stain faintly with eosin showed an increase in number (Figs. 3 and 6). The cell appeared more frequently when mitoses of eosinophile cells were abundant. Sometimes two of the cells appeared side by side as was described for the chromophobe cell. Although there has not been any report on the "droplet-nucleus" in the anterior lobe, it is probable that the cell containing such nucleus will have an intimate relationship with a certain special secretory activity or with a special mitotic phase.