Immunohistochemical Study on the C-cells in the Internal Parathyroid Gland of the Goat

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1 Immunohistochemical Study on the C-cells in the Internal Parathyroid Gland of the Goat Takeshi TSUCHIYA Department of Animal Morphology, Faculty of Agriculture, Tohoku University, Sendai-Shi 980 (Received September 7, 1983) Abstract The C-cells in the internal parathyroid glands (PGsIV) of 13 goats aged from 1 day to 3 years old were examined by the immunohistochemical method. The PGsIV were found in the thyroid glands of 12 out of 13 goats. They were located medially in the middle region of the thyroid gland. The C- cells in the PGsIV were found in 9 out of 12 goats, and were located mainly in the periphery of the PGsIV. The proportion of C-cells to parathyroid cells was low ( %). C-cells were not observed in the thymic tissues, either in the thyroid glands of 2 out of 13 goats or in the external parathyroid glands. PGsIV occurrence in thyroid glands and the C-cell occurrence in the PGsIV did not vary with age. Jpn. J. Zootech. Sci., 59(1): 49-53,1988 Key words: C cell, immunohistochemistry, internal parathyroid, goat C-cells synthesize and secrete calcitonin, a polypeptide hormone with serum calcium-lowering properties, and are found in the thyroid gland of mammalian species. Recently C-cells have been found to exist precisely in the internal parathyroid glands (PGsIV) of the dog, cat, rat, goat and rabbit by histochemical,2) and immunohistochemical methods3). KAMEDA1-3) showed that thymic tissues were often present in the thyroid glands of the cat and dog, but not in those of the goat. RoY et al.4) showed that PGsIV were embedded in the thyroid glands of 19 out of 26 goats studied and that thymic tissues in the glands of 7 out 26. The present study was conducted in order to define PGsIV and thymic tissue occurrnce and C-cell occurrence in the goat thyroid glands of the two age groups. Materials and Methods The thyroids and external parathyroid glands (PGsIII) were collected from 13 goats which were divided in to two age groups. One group was composed of kids aged l day and 14 days and the other of adults aged 1 year and 3 years. After slaughter, the thyroids and PGsIII taken were fixed in Bouin's solution or glutaraldehyde-picric-acetic Jpn. J. Zootech. Sci., 59(1):

2 TSUCHIYA thickness. The sections were stained by the immuno-enzymehistochemical PAP method (STERNBERGER et al.5)). For the dilution of all the reagents and rinsing steps, 0.01 M phosphate buffer saline (ph 7.2) was used. The following media were applied ; 1) rabbit antiporcine-calcitonin serum (Yamanouchi, Tokyo) (dil. 1 : 3200) ; 2) goat antirabbit IgG serum (Fujizoki, Tokyo) (dil. 1 : 20) ; 3) PAP complex (Cappel, Pennsylvania) (dil. 1 : 50) ; 4) 3, 3-diaminobenzidine solution + H202 (Nakarai, Kyoto). The sections were counterstained with Carazzi's hematoxylin. After staining the sections were dehydrated in ethanol, cleared in xylene and mounted in balsam. The specificity of the immunocytochemical staining was tested by 1) omitting either one of the rabbit anticalcitonin serum, the goat antirabbit-igg serum, or the PAP complex ; 2) replacing the rabbit anticalcitonin serum until specific staining disappeared. In these control stainings, the immunocytochemical reaction was completely prevented. Results PGsIV and thymic tissue occurrence in goat thyroid glands, and C-cell occurrence in such glands were shown in Table 1. The PGsIII were observed in all the goats examined. The thymic tissues were observed in the thyroid glands of 2 out of 13 goats (Fig. 1). The PGsIV were present within the thyroid glands of 12 out of 13 goats (Fig. 2). The last cells were cuboidal or ellipsoidal in shape and located medially in the middle regions of the thyroid gland. The C-cells in the thyroid were found singly or in chains of two or three cells with fine protrusions. Most of the C-cells were located in the intrafollicular position and only rarely in the interfollicular position. The C-cells were irregularly polyhedral or ellipsoidal in shape with long cytoplasmic projections. Table 1. The occurrence of the internal parathyroid gland (PGsIV) and thymic tissue in the thyroid glands, and that of the C-cells in ther glands of goats aged from 1 day to 3 years (note : +present, -absent) 50

3 C cell in the Goat Internal Parathyroid Figs The sections stained for C-cells by the PAP method using rabbit antiporcine calcitonin serum diluted 1 : Counterstained with Carazzi's hematoxylin. Fig. 1. The thymic tissue in a goat thyroid gland. Fig. 2. The internal parathyroid gland (PGIV) in a goat thyroid gland. The PGIV's cells are cuboidal or ellipsoidal shape and located medially in the middle regions of a thyroid gland. Fig. 3. The C-cells (arrows) in the PGIV. A few C-cells are located in the periphery of a PGIV. Fig. 4. The C-cells (arrows) in the PGIV. Several C-cells are located in the central region. The C-cells in the PGsIV were found in 9 out of 12 goats. Their shape and size were the same as those of the thyroid C-cells. Although the C-cells were usually found in the periphery of the PGsIV, which occupied % proportion with respect to parathyroid cells, a few C-cells were also observed in the central region of PGsIV (Figs. 3,4). The PGsIV were present within the thyroid glands in 7 out of 8 kids and in those of all the adult goats. The C-cells in the PGsIV were found in 5 out of 7 kids and in 4 out of 5 adult goats. The frequency of occurrence between the kids and adult goats showed no significant difference. Discussion The parathyroid glands of domestic ruminants usually consist of four glands, two on each side of the laryngeal area. They are designated as PGsIII and PGsIV. The PGsIII are located near the termination of the common carotid arteries. The PGsIV 51

4 TSUCHIYA lie near or within thethyoid gland6). RoY et al. 4) showed that the parathyroid glands were embedded in the thyroids of 19 out of 26 goats studied. all 3 goat thyroid glands contained PGsIV but no thymic tissues. 12 PGsIV and 2 thymic tissues were embedded in 13 goat thyroid glands. KAMEDA1,2) ascertained KAMEDA3) observed that In the present study, the presence of the PGsIV in the thyroid glands of 34 dogs, 15 cats, and 7 out of 8 rabbits, but none in those of 8 mice. The pig thyroid gland has no parathyroid gland7,8). These findings suggest that the varied occrrence of PGsIV in thyroid glands depends on the species. C-cells are found in the thyroid gland of many mammalian species. KAMEDA3) showed that in goats, C-cells are conspicuously elongated in shape and possess very long cytoplasmic protrusions. The observations in the present and previous study 14) are in agreement with her observations. C-cells have been verified as present in the PGsIV of the rabbit, cat, dog, and lion by the histochemical method1,2,9,10). Recently KAMEDA3) showed that by the immunohistochemical method C-cells were found in 9 out of 92 dogs in all 10 rabbits, in all 16 cats, and in all 3 goats. Furthermore, KAMEDA1,2) showed that the proportion of C-cells to parathyroid cells is 10% in the rabbit, 1-3% in the cat and very low in the dog. In this study, C-cells were observed in 9 out of 12 PGsIV and they occupied % in proportion to the parathyroid cells. STUX et al.11) found light cells in the two lobes of the rat thyroid glands, chiefly in the follicles in the central regions. A similar distribution of C-cells in the thyroid glands has also been reported by MCMILLAN et al. 12) and WOLF et al.13) in the normal adult human, and TSUCHIYA et al. 14) in the pig. KAMEDA1-3) and SOLCIA and SAMPIETRO15) showed that C-cells are more or less concentrated in the region adjacent to the PGsIV in the dog, cat, rabbit and goat. The present study clarified that the PGsIV were embedded medially in the middle regions of the thyroids, while the C-cells were more concentrated in the medial region near the PGsIV. These findings suggest that the distribution patterns of C-cells differ from species to species, and that this difference is reflected in the thyroid glands having PGsIV or not. References 1) KAMEDA, Y., Arch. histol. jpn., 33: ) KAMEDA, Y., Arch. histol. jpn., 33: ) KAMEDA, Y., Kawasaki Med. J., 7: ) RoY, K. S., R. P. SAIGAL, B. S. NANDA and S. K. NAGPAL, Anat. Anz., 13: ) STERNBERGER, L. A., P. H. HARDY, J. J. CUCULIS and H. G. MAYER, J. Histochem., 18: ) CALISLAR, T. and L. E. CLAIR, J. Dairy Sci., 57: ) LITTLEDIKE, E. T., Am. J. Vet. Res., 28: ) FETLER, A. W. and C. C. CAPEN, Acta anat., 75:

5 C cell in the Goat Internal Parathyroid 9) CARVALHEIRA, A. F. and A. G. E. PEARSE, Histochem., 8: ) DUMONT, L., Endocrinology, 17: ) STRUX, M., B. THOMPSON, H. ISLER and C. P. LEBLOND, Endocrinology, 68: ) MCMOLLAN, P. J., W. M. HOOKER and L. J. DEFOTS., Am. J. Anat., 140: ) WOLFE, H. J., E. F. VOELKEL and A. H. TASHJIAN, J. Clin. End. Metab,, 38: ) TSUCHIYA, T., Y. SHIOMURA, H. NAGAI and H. TAMATE, Acta anat., 120: ) SOLCIA, E. and R. SAMPIETRO, in Calcitonin. (TAYLOR, S. ed.) Springer, New York