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1.
The ultrastructure of the parathyroid glands of calcium-treated golden hamsters subjected to 5 gravity environment was studied. In the calcium-treated animals exposed to hypergravity environment, the Golgi complexes and cisternae of the granular endoplasmic reticulum were significantly decreased compared with those of the animals exposed to hypergravity environment only and appeared to increase compared with those of the calcium-treated animals, but were almost similar to those of the control animals. In addition, many chief cells contained some prosecretory granules in the Golgi areas, some secretory granules situated close to the plasma membrane and many lysosomes. The morphology of the parathyroid glands in the calcium-treated animals exposed to hypergravity environment resembled that of the control animals. These results suggest that the parathyroid glands suppressed by treatment of calcium and stimulated in response to hypergravity environment may indicate the secretory activity of the parathyroid glands of the control animals.  相似文献   

2.
The fine structure of the parathyroid glands of propranolol-treated hamsters subjected to 5 x gravity environment was studied. In the parathyroid glands of the propranolol-treated hamsters exposed to hypergravity environment, the volume density occupied by the Golgi complexes and cisternae of the granular endoplasmic reticulum was increased as compared to that of propranolol-treated hamsters and was decreased as compared to that of hamsters exposed to a hypergravity environment but was almost similar to that of control hamsters. In addition, many chief cells contained rich free ribosomes, abundant mitochondria and some secretory granules located in the peripheral cytoplasm. These findings suggest that the parathyroid gland which may be suppressed by treatment of propranolol and stimulated in response to a hypergravity environment indicates the secretory activity of the control parathyroid gland.  相似文献   

3.
The ultrastructure of the parathyroid glands of golden hamsters subjected to 5-gravity environment after administration of epinephrine was studied. In the epinephrine-treated animals exposed to a hypergravity environment, the Golgi complexes associated with numerous prosecretory granules were significantly increased compared with those of the control, centrifuged and epinephrine-treated animals, as well as the cisternae of the granular endoplasmic reticulum compared with those of the control and centrifuged animals. In addition, many secretory granules were situated close to the the plasma membrane of the chief cells in the epinephrine-treated animals exposed to a hypergravity environment. Those observations suggest that the secretory activity of the parathyroid gland may be markedly stimulated in the epinephrine-treated animals exposed to a hypergravity environment.  相似文献   

4.
The ultrastructure of the parathyroid glands of phosphate-treated golden hamsters exposed to a 5-G environment was studied. In the phosphate-treated animals exposed to a hypergravity environment, the Golgi complexes associated with numerous prosecretory granules, and the enlarged intercellular spaces containing floccular or finely particulate material showed a significant increase compared to those of the control, centrifuged, and phosphate-treated groups, and the cisternae of the granular endoplasmic reticulum showed a significant increase compared to those of the control and phosphate-treated groups. In addition, numerous secretory granules were situated close to the plasma membrane of chief cells in the phosphate-treated animals exposed to a hypergravity environment. These findings suggest that the synthesis, and to a greater extent the release of secretory granules may be markedly stimulated, in the parathyroid glands of phosphate-treated animals exposed to a hypergravity environment.  相似文献   

5.
The fine structure of the parathyroid glands of golden hamsters exposed to 2, 5 or 10 g environment for 5 h was studied. In the centrifuged hamsters, many secretory granules are located in a peripheral position just beneath the plasma membrane of chief cells, and the Golgi complexes and cisternae of the granular endoplasmic reticulum are significantly increased compared with those of control animals. There are no significant differences between the control and centrifuged animals with regard to secretory granules, large secretory granules, lysosomes, vacuolar bodies and lipid droplets. These findings suggest that the secretory activity of the parathyroid gland may be stimulated in response to hypergravity environment.  相似文献   

6.
The ultrastructure of the parathyroid glands of infantile, young, adult and senile golden hamsters subjected to a hypergravity environment was studied. In the parathyroid glands of 5-, 10- and 20-day-old, and 1- and 3-month-old golden hamsters exposed to a hypergravity environment, the Golgi complexes were significantly increased, and in 5-, 10- and 20-day-old, and 1- and 8-month-old animals exposed to a hypergravity environment, the cisternae of the granular endoplasmic reticulum appeared to be increased as compared to those of each control group. In addition, in centrifuged animals numerous prosecretory granules were observed in the Golgi areas, and many secretory granules were located in the peripheral cytoplasm. The ultrastructure of the parathyroid glands of 14-month-old centrifuged animals resembled that of 14-month-old control animals. These results suggest that the secretory activity of the parathyroid gland may be stimulated in infantile, young and adult golden hamsters subjected to a hypergravity environment and may not be stimulated in senile animals subjected to a hypergravity environment.  相似文献   

7.
Ultrastructural changes of the parathyroid glands of isoproterenol-treated golden hamsters were investigated. Many chief cells in the parathyroid glands after 5 and 10 minutes of administration of isoproterenol contain well-developed Golgi complexes and granular endoplasmic reticulum, numerous prosecretory granules, and many secretory granules in the peripheral cytoplasm as compared with the control animals. Many chief cells in the parathyroid glands after 1, 3, 6 and 12 hours of administration have poorly-developed Golgi complexes, granular endoplasmic reticulum, many secretory granules and numerous lipid droplets as compared with the control animals. The morphology of the parathyroid gland after 30 minutes and 24 hours of administration resembles that of the control animals. It is considered that isoproterenol affects the secretory activity of the parathyroid gland.  相似文献   

8.
The ultrastructure of the parathyroid glands of fetal and pregnant golden hamsters exposed to 5-gravity environment was studied. In the centrifuged fetal animals the Golgi complexes associated with some prosecretory granules were significantly increased compared with those of the control fetal animals, and several secretory granules were located in a peripheral position just beneath the plasma membrane. In the centrifuged pregnant animals the Golgi complexes associated with numerous prosecretory granules were significantly increased, cisternae of the granular endoplasmic reticulum appeared to be increased compared with those of the control pregnant animals, many secretory granules were located in the peripheral cytoplasm and several granules were situated close to the plasma membrane. These findings suggest that in the parathyroid glands of the fetal golden hamsters as well as the pregnant animals the synthesis and release of parathyroid hormone may be stimulated in response to a hypergravity environment.  相似文献   

9.
The ultrastructure of the parathyroid glands of hypophysectomized golden hamsters was studied. In the parathyroid glands of hypophysectomized animals the Golgi complexes and secretory granules were significantly decreased and large vacuolar bodies were significantly increased compared with those of the control animals. In addition, the chief cells contained a few prosecretory granules in the Golgi areas and a few secretory granules were present in the peripheral cytoplasm. These results suggest that the synthesis and release of parathyroid hormone may be suppressed in the parathyroid glands of the hypophysectomized animals.  相似文献   

10.
Effects of 5-gravity environment on the ultrastructure of the parathyroid glands of norepinephrine-treated golden hamsters were studied. In the centrifuged animals treated with norepinephrine, the volume density occupied by the Golgi complexes associated with numerous prosecretory granules was significantly increased compared with that of the control, centrifuged and norepinephrine-treated animals, as well as the volume density occupied by the cisternae of the granular endoplasmic reticulum compared with that of the control and centrifuged animals. In addition, in the centrifuged animals treated with norepinephrine, numerous secretory granules were situated close to the plasma membrane. It is suggested that the synthesis and release of secretory granules may be markedly stimulated in the parathyroid glands of the norepinephrine-treated golden hamsters subjected to a hypergravity environment.  相似文献   

11.
Ultrastructural changes of the parathyroid glands of pinealectomized golden hamsters were investigated. The main changes in the parathyroid glands 1 hour and 1 day after pinealectomy compared with the control and sham-operated groups were an increase of the Golgi complexes, cisternae of the granular endoplasmic reticulum and large vacuolar bodies. In addition, many chief cells contained numerous prosecretory granules in the Golgi areas and many secretory granules in the peripheral cytoplasm. The morphology of the parathyroid glands 7 and 30 days after pinealectomy resembled that of the control parathyroid glands. These results suggest that pinealectomy affects the secretory activity of the parathyroid gland.  相似文献   

12.
Ultrastructural changes of the parathyroid glands of melatonin-treated golden hamsters were studied. Many chief cells in the parathyroid glands after 1 hour of administration of melatonin contained poorly-developed Golgi complexes associated with a few prosecretory granules and numerous lipid droplets as compared with those of the control animals. The morphology of the parathyroid glands after 5 hours of administration resembled that of the control animals. Many chief cells in the parathyroid glands after 24 hours of administration had well-developed Golgi complexes and cisternae of the granular endoplasmic reticulum, numerous prosecretory granules, a few lipid droplets and many secretory granules in the peripheral cytoplasm as compared with those of the control animals. The ultrastructure of the parathyroid glands after 48 hours of administration was almost similar to that of the control animals. It is considered that melatonin affects the secretory activity of the parathyroid gland.  相似文献   

13.
The ultrastructure of the parathyroid glands of adult Japanese lizards (Takydromus tachydromoides) in the spring and summer season was examined. The parenchyma of the gland consists of chief cells arranged in cords or solid masses. Many chief cells contain numerous free ribosomes and mitochondria, well-developed Golgi complexes, a few lysosome-like bodies, some multivesicular bodies and relatively numerous lipid droplets. The endoplasmic reticulum is mainly smooth-surfaced. Cisternae of the rough endoplasmic reticulum are distributed randomly in the cytoplasm. Small coated vesicles of 700-800 Å in diameter are found occasionally in the cytoplasm, especially in the Golgi region. The chief cells contain occasional secretory granules of 150-300 nm in diameter that are distributed randomly in the cytoplasm and lie close to the plasma membrane. Electron dense material similar to the contents of the secretory granules is observed in the enlarged intercellular space. These findings suggest that the secretory granules may be discharged into the intercellular space by an eruptocrine type of secretion. Coated vesicles (invaginations) connected to the plasma membrane and smooth vesicles arranged in a row near the plasma membrane are observed. It is suggested that such coated vesicles may take up extracellular proteins. The accumulation of microfilaments is sometimes recognized. Morphological evidence of synthetic and secretory activities in the chief cells suggests active parathyroid function in the Japanese lizard during the spring and summer season.  相似文献   

14.
Electron-microscopic studies were made on the parathyroid gland of cadmium-treated mice. Most chief cells in treated mice were rich in free ribosomes and secretory granules compared to the control mice. In the parathyroid gland after 3 and 4 weeks of administration of cadmium, interdigitations between adjacent chief cells became more complex than in the control mice. In most chief cells of the parathyroid gland after 2, 3 and 4 weeks of administration of cadmium, the Golgi complexes associated with numerous prosecretory granules were better developed than in the control mice. These ultrastructural appearances suggest that parathyroid gland cellular activity was stimulated in response to cadmium treatment.  相似文献   

15.
The normal parathyroids of six humans and a Virginia deer were studied by light and electron microscopy. The parenchyma of the deer parathyroid is composed of uniform chief cells, which contained 100 to 400 mµ electron-opaque, membrane-limited granules, presumed to be secretory granules, in addition to the usual cytoplasmic organelles. Desmosomes are present between adjacent cells, and rare cilia are observed protruding from the chief cells into the intercellular space. The human parathyroids contain chief cells in two phases—active and inactive—as well as oxyphil cells. Active chief cells have a large Golgi apparatus, sparse glycogen, numerous secretory granules, and rare cilia. Inactive chief cells contain a small Golgi apparatus, abundant glycogen, and few secretory granules. Both forms have the usual cytoplasmic organelles and, between adjacent cells, desmosomes. Oxyphil cell cytoplasm is composed of tightly packed mitochondria and glycogen granules, with rare secretory granules. Cells with cytoplasmic characteristics intermediate between chief and oxyphil cells, possibly representing transitional cells, have been observed. Secretory granules of both man and deer are composed of 100 to 200 A particles and short rods, and the granules develop from prosecretory granules in the Golgi region of the cell. The human secretory granules are smaller and more variable in shape than those of the deer. The granules are iron and chrome alum hematoxylin-positive, argyrophilic, and aldehyde fuchsin-positive, permitting light microscopic identification. They are also found in the capillary endothelial cells of the parathyroid and in its surrounding connective tissue. The secretory granules of the parathyroid cells can thus be followed from their formation in the Golgi apparatus almost to their extrusion into the blood stream.  相似文献   

16.
Summary The secretory mechanism of the parathyroid glands of fluoride treated rats is evaluated ultrastructurally and compared to that of control rats. The principal difference between the two groups of rats concerns the rate of activity of the chief cells of the gland. In the control animals, these cells are predominantly inactive. In the fluoride-treated rats, they exhibit a more active stage of the secretory cycle. The active chief cells in rats treated with fluoride contain increased numbers of secretory granules. These granules are released into the perivascular spaces within cytoplasmic projections suggesting an apocrine-like mechanism for the secretion of parathyroid hormone. Secretory granules are observed free in the perivascular spaces and within the cytoplasm of capillary endothelial cells in the parathyroid glands.  相似文献   

17.
Summary Kittens with an immature skeleton fed exclusively a calcium-deficient beef heart diet for 1 to 14 weeks developed hypocalcemia, parathyroid hyperplasia, and generalized osteitis fibrosa. Initial ultrastructural changes in the stimulated parathyroid glands were observed after 1 week and consisted of increased cytoplasmic volume, aggregation of the granular endoplasmic reticulum, and enlargement of the Golgi apparatus associated with increased numbers of prosecretory granules. After 3 weeks, chief cell hyperplasia was first observed and the numbers of mature secretory granules were greatly reduced. The hyperactive chief cells remained degranulated until the termination of the experiment. Stimulated chief cells accumulated glycogen in excess of controls and contiguous chief cells had intricately interdigitated plasma membranes. The parathyroid glands of experimental cats after being fed the low calcium diet for 14 weeks contained primarily hyperactive and vacuolated light chief cells with an occasional transitional water-clear cell.This investigation was supported in part by the Morris Foundation and grant GM 1052, National Institutes of Health, United States Public Health Service. The authors wish to acknowledge the technical assistance of Mr. D. Q. Davis and Mr. O. R. Kindig.  相似文献   

18.
The ultrastructure of the parathyroid gland in golden hamsters after long-term treatment with ethanol was studied. Male hamsters of experimental groups were given ethanol at the concentration of 7% for 3 and 5 months with food and water freely available. In the ethanol-treated hamsters, the Golgi complexes associated with many prosecretory granules were well developed and many secretory granules were located near the plasma membrane as compared with those of the control animals. Exocytotic events were observed in 5-month-treated animals. These findings suggest that the secretory activity of the parathyroid gland is stimulated after long-term treatment with ethanol.  相似文献   

19.
We qualitatively and quantitatively investigated parathyroid glands of the UM-X7.1 cardiomyopathic hamster at 1, 2, 6 and 12 months of age to compare them with those of the normal hamster. We found that at 1 month of age in the UM-X7.1 hamster, the Golgi apparatus, lipid droplets and secretory granules decreased. There were no significant differences between the UM-X7.1 hamster and the control hamster at 2 months of age. At 6 months of age, the Golgi apparatus, rER and the secretory granules significantly increased in the UM-X7.1 hamster. At 12 months of age, the Golgi apparatus and lysosomes increased, while the secretory granules decreased. Ultrastructurally, we consider that in the UM-X7.1 hamster, the synthesis and release of the parathyroid at 6 months of age may be activated by an excessive amount of circulating catecholamine, and the functional activity of the parathyroid glands at 12 months of age may be depressed by the increased plasma calcium level. These findings suggest that the activities of the synthesis and release of the parathyroid hormone were the highest at 6 months of age in the UM-X7.1 hamster.  相似文献   

20.
Summary The effect of a low calcium diet on the ultrastructure of the parathyroid gland in the chick was examined. Two-week-old White Leghorn chicks were fed a low calcium diet (calcium content 0.63%) for two weeks. In these chicks, the parathyroid glands are grossly enlarged. Hypertrophy and hyperplasia of the chief cells are evident. The plasma membranes between adjacent cells are relatively straight but interdigitate in some places. Chief cells contain occasional membrane-limited secretory granules (150–350 m in diameter) and with contents of variable electron density. Secretory granules are distributed randomly but some are closely applied to the plasma membrane. There is an increase in the development of the rough-surfaced endoplasmic reticulum. The Golgi complex is enlarged and consists of cisternae arranged in concentric layers, smooth-surfaced and coated vesicles and condensing vacuoles. Dilatations of the cisternae at several points are observed. Mitochondria and filaments are also encountered. These morphological features suggest that low calcium intake stimulates the synthetic activity of the chief cells of the chick parathyroid.  相似文献   

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