Dept. of Anat., Kyoto Prefectural Medical College (Director: Prof. Dr. H. NODA).

Transcription

1 Arch. hist. jap. Vol. 18, n. 3 (December 1959). P Dept. of Anat., Kyoto Prefectural Medical College (Director: Prof. Dr. H. NODA). Histological Studies on the Adenohypophysis. I. Argyrophil Cells (Barrier Cells) in the Intermediate Lobe. (Contributions to the Comparative Histology of the Hypothalamo-hypophysial System. 43rd report.) (Received August 19, 1959.) In the course of the investigation of neuroglia elements in the hypothalamohypophysial system of dog and cat by various silver impregnation methods, we chanced to notice the constant presence of uniquely looking argyrophilic cells among the intermediate lobe cells in the sections treated by YANO's silver impregnation method (borax-formalin method) for neuroglia. The whole view of them looks just like a barrier. These argyrophilic cells-we delved later into literature-correspond to those described by LOTHRINGER (1886), BERKLEY (1894), RETZIUS (1894), GEN- TES (1903), GEMELLI (1906), HERRING (1908), TRAUTMANN (1909), KOHN (1909), STENDELL (1914), BENDA (1931), and recently by OBERTI (1957). They observed by GOLGI method and other silver impregnation methods. Findings on these cells described by them, however, are strikingly different in form, origin, and function from each other. The following is the result of our own observations. I. Material and Methods. From ten adult dogs and two adult cats containing both sexes, we removed the hypophysis as fresh as possible and fixed them in formalin, formalin-alcohol-acetic acid mixture, formalin-ammonium bromide, BOUIN's fluid, CHAMPY's fluid or ZENKER's fluid. To the freezing sections we applied DEL RIO HORTEGA's silver carbonate methods for astrocytes, for oligodendroglia and for microglia, YANO's borax-formalin method for neuroglia and GROS-SCHULTZE's silver method for neurofibril. To the paraffin sections we applied hematoxylin-eosin, azan, GOMORI's chrome alum hematoxylin-phloxine method, MALLORY's phosphomolybdic acid hematoxylin, HEIDENHAIN's iron hematoxylin, SEVERINGHAUS' method, gallocyanin, BODIAN's protargol method, and BIELSCHOWSKY-MARE-SCH-SANO's silver method for lattice-fiber. Further, we used for reference the specimens, in which the intravascular injection of India ink had been performed. 457

2 458 Y. SANO, O. SAITO and Y. ISHIDA: II. Observations. The argyrophilic cells of the intermediate lobe, now in question, can be silverimpregnated by DEL RIO RORTFGA's silver carbonate method, but much better by YANO's borax-formalin method. By the latter method their whole figures appear very clearly. First, we observed the lobus intermedius treated by YANO's method. It was possible even by weak magnification to see argyrophilic fibres between the cell strands. They run through the lobus intermedius parallel to the cell strands and vertical to the wall of the pituitary cleft. These argyrophilic fibres terminate with one end in the wall of the hypophysial cavity and with the other in the boundary between lobus intermedius and lobus posterior, both ends forming an enlargement shaped 'fussartig'. These fibres are always continued, somewhere in their course, Fig. 1. A schema of the argyrophil cells in the lobus intermedius. to a cell body of comparatively large size, which are round, oval, or spindle-shaped. Namely, these argyrophilic fibres are processes of either bipolar or multipolar cells, and never exist as fibres only, independent of the cell. The degree of impregnation is intenser in the process than in the cell body. though the cell body and the nucleus are also well impregnated. The process generally runs straight, but occasionally divides or makes anastomosis. The argyrophilic cells are often found in groups and not equally distributed in the lobus intermedius. As stated above, the processes end in enlargements in the luminal surface of the hypophysial cavity. And, each enlargement is cone-shaped, with its base on the luminal surface. They connect together closely in such a manner that they separate gland-cells of the intermediate lobe from each other and from the luminal surface. In like manner another ends terminate in the boundary between the intermediate and posterior lobes, but some

3 Argyrophil Cells in the Intermediate Lobe. 459 Fig. 2. Argyrophil cells in the lobus intermedius of dog. From above to below, posterior lobe, intermediate lobe, hypophysial cavity. Formalin ammonium bromide fixa- of them go further beyond the boundary to get into the posterior lobe. According to these findings the argyrophilic cells seem as if they support the intermediate lobe with their processes ending in enlargement, and adjust the arrangement of cell strands. It is impossible to stain these cells with hematoxylin-eosin, iron hematoxylin or MALLORI's phosphomolyhdic acid hematoxylin. By these methods, no effect of staining could be obtained as to the cell body and the process, except the terminal enlargement, the structureless form of which could be perceived by its homogeneous tone. GOMORI's CH-P staining also has no effect on these cells, and azan staining succeeds only in showing the process in light red-violet. Then, we turned to the section stained by BIELSCHOWSKY-MARESCH-SANO's silver method for lattice fiber. The lattice fibers were found to be scanty in the intermediate lobe where vascular supply is poor in such animals, because the lattice fibers here are mostly

4 460 Y. SANO, O. SAITO and Y. ISHIDA: those following the vascular system. For this reason, we cannot regard the argyrophilic cells and their processes as connective tissue elements. By SE VERINGHAUS' method the cell body and processes were stained red, and the oval or spindle-shaped nucleus was seen more or less clearly. And purple-blue fine granula could often be seen in the cell-body. By referring to the specimen of intravascular injection of India ink, it was clear that the argyrophilic cells are totally different from endothelial cells reported by BENDA (1931). By GROS-SCHULTZE's and BODIAN's methods for nerve fiber impregnation, we found it impossible to impregnate these cells and processes. The argyrophilic cells and their processes become irregular in arrangement as they approach to the 'Umschlagszone'. So their findings are unclear in this region. III. Consideration. We knew from the above-mentioned findings that the argyrophilic cells were neither connective tissue elements nor vasular endothelial cells. KOHN (1909) states that 'die saulenformigen und zylindrischen Elemente des Epithelsaumes' are 'feine kernfuhrende Bindegewebsseptula'. However, we can not consider the processes of the argyrophilic cell to be connective tissue septula, because they are almost insus ceptible to anilin blue staining, and can not be silvered by the impregnation method for lattice fiber. BENDA (1931) stated that these cells were nothing but capillar's endothelium. But, as clearly seen in our sections of intravascular injection of India ink, the intermediate lobe of dog or cat has only poor vascular supply. And the connective tissue fibers here belong mostly to the blood-vessel. Therefore, they show a quite different distribution from that of the argyrophilic cells. The cells described by BENDA (1931) might be other ones than those which were accurately by TRAUTMANN and others. described It is evident that the argyrophilic cells are not nervous elements, since their cell bodies and processes cannot be impregnated by GROS-SCHULTZE's method or BODIAN's protargol method, and besides they contain no NISSL's substance. These cells can be impregnated well especially by the method for neuroglia. So it can be questioned if they might be neuroglia elements. TRAUTMANN (1909) and STENDELL (1914) thought, as many others did, that the argyrophilic cells might be neuroglia elements wandering out of the neurohypophysis into the lobus intermedius. And they considered these cells to be ependymal cells. Their opinions, however, are not based on the histogenetic observations, but on the inference from the fact that the cells can be impregnated with silver. So, as was pointed out by ROMEIS (1940), their views have no reliable proof. ROMEIS (1940) supposes these cells to correspond with his so-called 'hyperchromatische Zellen'. We also are not necessarily against ROMEIS' opinion that these are the cells proper to the intermediate lobe, but we cannot agree with the view that the cells are 'hyperchromatische Zellen', because we know that they have clear nucleus structure, and present no image of pycnosis in sections stained by azan or SEVERINGHAUS' method. The enlargement in which the argyrophilic fiber ends on the wall of the hypophysial cavity reminds us of the marginal cell in rodents, written by YAMADA

5 Argyrophil Cells in the Intermediate Lobe. 461 (1933). In the dog or the cat, however, it is difficult to distinguish a YAMADA's marginal cell. And besides, the bodies of argyrophilic cells are found sporadically at various levels in the intermediate lobe. For such reasons we believe that the two are different. That the argyrophilic cells are found somewhat in groups, their weak susceptibility to staining with common dyes, and the above-mentioned various findings combine to give us the impression that they may correspond to the 'undifferenzierte Zellen' of ROMEIS. It may be supposed that the argyrophilic cells can serve in some way or other to support the cell strands of the lobus intermedius, but there is as yet not enough proof to decide whether or not they are indifferentiate cells on the way to becoming typical intermedia cells. Another guess is that they may have some role in the functional mutual relations between the lobus intermedius and the lobus posterior. At the present stage cells of the lobus inter- what we can say for certain is that they are either intrinsic medius or neuroglia elements. IV. Summary. The argyrophilic cells in the lobus intermedius of dog and cat were studied. 1. This argyrophilic cell and its processes are impregnated with silver especially well by YANO's borax-formalin method for neuroglia and by RIO HORTEGA's silver carbonate method. 2. This cell can not be stained by GOMORI's CH-P method, GROS-SCHULT- ZE's method and BODIAN's method for nerve fiber. The cell has no NISSL substance. It can not be silvered by BIELSCHOWSKY-MARESCH-SANO's method for lattice fiber. 3. These argyrophilic cells have their perikaryons at various levels in the lobus intermedius and extend bipolar or multipolar processes which end in cone-like enlargements on the wall of the hypophysial cavity and in the connective tissue between intermediate and posterior lobes. Some processes go further into the lobus posterior. 4. The argyrophilic cell is neither a connective tissue element nor a nerve cell. There is not enough proof to decide that the cell is a neuroglia cell or that it is what nature and its relations with the neurosecretory system, but it may be supposed to be a cell participating in the mutual functional relations between intermediate and the posterior lobes.

6 462 Y. SANG, O, SAITO, and Y. ISHIDA. References. Benda, C.: Jaffes Anatomie und Pathologie der Spontanerkrankungen der kleinen Laboratoriumstiere. Hypophysis cerebri S Berkley, H. J.: J. Brain 17 (1894). P Cited by B. Romeis. -Gemelli, A.: Anat. Anz. 28 (1906). S. 613 u. S Gentes, L.: C. r. Soc. Biol. 55 (1903). P. 100, P. 336 et P Herring, P. T.: Q. J. exper. Physiol. 1 (1908). P. 121 a. P Kohn, A.: (1909). Cited by Romeis. -Lothringer, S.: Arch, mikr. Anat. 28 (1886). S Oberti, C.: Z. Zellforsch. 46 (1957). S Retzius, G.: Biol. Untersuch., Neue Folge 6 (1894). S Romeis, B.: Mollendorffs Handbuch der mikoskopischen Anatomic des Menschen. Bd. 6, Tl. 3. Innersekretorische Drusen. II. Hypophyse Stendell, W.: Oppels Lehrbuch der vergleichenden mikroskopischen Anatomie der Wirbeltiere. Bd. 8. Die Hypophysis cerebri Trautmann, K.: Fol. Psychiatr. et Neurol. Jap. 10 (1956). P. 12. Adress of authors: Dr. Y. SANO et al. Department of Anatomy, Kyoto Prefectural Medical College. Kawaramachi-Hirokoji, Kamikyo-Ku, Kyoto. Japan.