Jun Hara

Some features of the structure and histochemistry of the rat parathyroid gland.

SummarySome features of the structure and histochemistry of the rat parathyroid gland have been studied using a variety of histological and histochemical staining methods. The gland is composed of a compact parenchyma consisting essentially of a single cell type. The parenchyma is encapsulated by a connective tissue layer which extends into it and holds abundant branches of blood vessels. In the parenchymal cells four types of protein granules are demonstrated by the tetrazonium, DDD-diazo blue B, alkaline tetrazolium and HNAH-diazo blue B methods respectively. The DDD-diazo blue B reactive granules are considered to relate to the secretory activity of the parenchymal cells in view of their morphology and recent biochemical data on the nature of parathyroid hormone. The cytophysiological significance of the other three types of protein granules was discussed on the basis of their morphological features. Besides protein granules the parenchymal cells contain glycogen, RNA and DNA, and are reactive for alkaline phosphatase. The quantity of these substances and the enzyme activity seem to reflect to a certain extent different states of cellular activity. The parenchymal cells show scanty sudanophilic lipid content in paraffin sections and are devoid of basophilic mucopolysaccharides. Further, the cells are negative for acid phosphatase. In the connective tissue stroma of the gland the vascular endothelial cells show high alkaline phosphatase activity, and a hypothesis is presented as to the physiological significance of this high enzyme activity.

CHEMOCYTOLOGICAL OBSERVATIONS ON THE PARATHYROID GLAND OF THE TOAD (BUFO VULGARIS JAPONICUS) IN SPECIMENS TAKEN THROUGHOUT THE YEAR.

SummaryThe parathyroid gland of the toad (Bufo vulgaris japonicus) has been studied histochemically in specimens taken throughout the year.1.The organ contains varying proportions of large peripheral and small central parenchymal cells and is covered with a vascular and connective tissue envelope.2.The parathyroid cells contain 2,2′-dihydroxy-6,6′-dinaphthyl disulfide (DDD) diazo blue B reactive protein granules, 2-hydroxy-3-naphthoic acid hydrazide (HNAH) diazo blue B reactive protein granules, coupled tetrazonium proteins, glycogen, and ribonucleic acid (RNA).3.Seasonal differences in the DDD diazo blue B reactive granules suggest that they reflect the secretory activity of the parathyroid cells.4.The morphological feature of the HNAH diazo blue B reactive granules throughout the year is suggestive of their dual nature; the majority of the granules represent a mitochondrial pattern of the parathyroid cells, while their minority appearing to be of another cytophysiological significance such as the relation to the cellular activity of secretion.5.The nuclear and cytoplasmic coupled tetrazonium reaction of the parathyroid cells is regarded as an indicator by which the extent of the cellular physiological activity is adequately reflected throughout the year.6.The seasonal variation in the glycogen content of the parathyroid cells appears to indicate that this polysaccharide is present for the performance of the cellular activity; secretory and metabolic.7.The cytoplasmic RNA of the parathyroid cells exhibits seasonal rise and fall in amount and its amount appears linked almost linearly to the cytoplasmic protein synthetic activity for either secretion or metabolism.8.From the reactions of the peripheral and central parathyroid cells for proteins and amino acids, glycogen and RNA, the former cells are concluded to be more active in secretory function than the latter.

The chemocytology of the parathyroid glands of the rat after bilateral nephrectomy.

SummaryChemocytological observations were made on the parathyroid gland of the rat after stimulation by bilateral nephrectomy and the following results were obtained.1.DDD diazo blue B reactive granules are increased appreciably in amount and staining ability in the parenchymal cells at 12 and 24 hours after the operation, but tend to decrease slightly at a postoperative period of 36 hours. This type of protein granules is considered to be a reflection of the secretory activity of the parenchymal cells.2.HNAH diazo blue B reactive granules appear to behave in a similar manner in the cells upon the experimental stimulation. The morphology of these granules, however, has led us to the conclusion that they are not identical with DDD diazo blue B reactive granules and seem to represent in part mitochondrial proteins.3.Glycogen granules are found to almost disappear in the parenchymal cells at 12 hours after bilateral nephrectomy, but tend to reappear with further lapse of postoperative time. It seems likely that this polysaccharide is utilized, possibly as an energy source, for the protein synthetic and therefore functional activity of the cells.4.Cytoplasmic RNA as revealed by pyronin stain, is increased in amount and stainability in the parenchymal cells at 12 and 24 hours after the operation, but tend to show a slight decline at 36 hours. These changes in the RNA content of the cells are interpreted as manifesting to a great extent the rise and fall of the rate of protein synthesis under the experimental condition.5.With the exception of cases with a certain number of animals, alkaline phosphatase activity is significantly higher in the parenchymal cells at 12 and 24 hours after bilateral nephrectomy, as compared with that under normal condition. As the postoperative time lapse grows up to 36 hours, the alkaline enzyme activity becomes a little less intense in the cytoplasm of the cells. It can be presumed that alkaline phosphatase activity may be associated, though in an unknown manner, with the physiological functions of the parenchymal cells.6.The experimental stimulation of the parathyroid gland by bilateral nephrectomy does not cause any remarkable effect upon the chemocytological features of the interstitial connective tissue constituents including the vascular endothelial cells.7.The parathyroid gland of animals undergone decapsulation of the kidneys does not reveal any chemocytological response. Finally, the present experimental data do not show any significant difference due to the sex of animals employed.