scholarly journals ISOLATION AND BIOLOGICAL PROPERTIES OF SECRETORY GRANULES FROM RAT ANTERIOR PITUITARY GLANDS

1969 ◽  
Vol 43 (3) ◽  
pp. 564-574 ◽  
Author(s):  
Allen Costoff ◽  
W. H. McShan
Keyword(s):  
Electron Microscopy ◽  
Anterior Pituitary ◽  
Close Agreement ◽  
Secretory Granules ◽  
Cell Types ◽  
Pituitary Hormones ◽  
Biological Properties ◽  
Single Fraction ◽  
Rat Pituitary ◽  
Pituitary Glands

A method is described for the isolation of secretory granules from rat anterior pituitary glands. The method consists of differential and isopycnic gradient centrifugations, followed by filtration of the zones containing granules on Nuclepore filters to remove mitochondria. Highly purified granules were obtained as indicated by electron microscopy. Major parts of the thyrotropin (TSH) and adrenocorticotropin (ACTH) were recovered in a single fraction of granules as were follicle-stimulating (FSH) and luteinizing (LH) hormones. The somatotropin (STH) and prolactin (LTH) were recovered in separate granule fractions. The major parts of the six different hormones were associated with their respective granule fractions as shown by bioassays specific for each of the hormones. The diameters of granules in sections of intact rat pituitary glands and in isolated pellets were measured, and the means and ranges were in close agreement. These results contribute to the identification of the cell types which produce the different pituitary hormones.

ELECTROPHORETIC SEPARATION OF HORMONES ASSOCIATED WITH SECRETORY GRANULES FROM RAT ANTERIOR PITUITARY GLANDS

1970 ◽  
Vol 63 (2) ◽  
pp. 378-384 ◽  
Author(s):  
D. R. Hodges ◽  
W. H. McShan
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Secretory Granules ◽  
Follicle Stimulating Hormone ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Disc Electrophoresis ◽  
Hormone Activity ◽  
Pituitary Glands ◽  
Stimulating Hormone

ABSTRACT Electrophoretic analyses of rat, mouse, human and cow anterior pituitary homogenates with subsequent bioassays for hormonal activity have been reported. Comparison of the behaviour of the hormonal activities from rat anterior pituitary secretory granules and that reported for pituitary homogenates was made following disc electrophoresis on polyacrylamide gels. Bioassays of gel segments for the six anterior pituitary hormones resulted in the localization of the activities of five of the six hormones. ACTH activity was not detected. Growth hormone and prolactin were associated with the major cathodal and anodal discs respectively. Luteinizing hormone and thyroid stimulating hormone activities had similar mobilities and were located in a zone just above growth hormone. The activity was not restricted to a discrete, stainable disc in either case. Follicle stimulating hormone activity was detected in a narrow segment containing only one disc a few millimeters below growth hormone. Comparison of the mobilities of the hormones from homogenates and secretory granule extracts suggests that they have essentially similar electrophoretic characteristics at basis pH.

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

scholarly journals LYSOSOME FUNCTION IN THE REGULATION OF THE SECRETORY PROCESS IN CELLS OF THE ANTERIOR PITUITARY GLAND

1966 ◽  
Vol 31 (2) ◽  
pp. 319-347 ◽  
Author(s):  
Robert E. Smith ◽  
Marilyn G. Farquhar
Keyword(s):  
Anterior Pituitary ◽  
Dense Body ◽  
Secretory Granules ◽  
Secretory Process ◽  
Secretory Cells ◽  
Residual Body ◽  
Multivesicular Bodies ◽  
Dense Bodies ◽  
Pituitary Glands ◽  
Secretory Products

The nature and content of lytic bodies and the localization of acid phosphatase (AcPase) activity were investigated in mammotrophic hormone-producing cells (MT) from rat anterior pituitary glands. MT were examined from lactating rats in which secretion of MTH1 was high and from postlactating rats in which MTH secretion was suppressed by removing the suckling young. MT from lactating animals contained abundant stacks of rough-surfaced ER, a large Golgi complex with many forming secretory granules, and a few lytic bodies, primarily multivesicular bodies and dense bodies. MT from postlactating animals, sacrificed at selected intervals up to 96 hr after separation from their suckling young, showed (a) progressive involution of the protein synthetic apparatus with sequestration of ER and ribosomes in autophagic vacuoles, and (b) incorporation of secretory granules into multivesicular and dense bodies. The content of mature granules typically was incorporated into dense bodies whereas that of immature granules found its way preferentially into multivesicular bodies. The secretory granules and cytoplasmic constituents segregated within lytic bodies were progressively degraded over a period of 24 to 72 hr to yield a common residual body, the vacuolated dense body. In MT from lactating animals, AcPase reaction product was found in lytic bodies, and in several other sites not usually considered to be lysosomal in nature, i.e., inner Golgi cisterna and associated vesicles, and around most of the immature, and some of the mature secretory granules. In MT from postlactating animals, AcPase was concentrated in lytic bodies; reaction product and incorporated secretory granules were frequently recognizable within the same multivesicular or dense body which could therefore be identified as "autolysosomes" connected with the digestion of endogenous materials. Several possible explanations for the occurrence of AcPase in nonlysosomal sites are discussed. From the findings it is concluded that, in secretory cells, lysosomes function in the regulation of the secretory process by providing a mechanism which takes care of overproduction of secretory products.

scholarly journals Cell Fractionation of Anterior Pituitary Glands from Beef and Pig

1959 ◽  
Vol 5 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Frank S. Labella ◽  
J. H. U. Brown
Keyword(s):  
Alkaline Phosphatase ◽  
Anterior Pituitary ◽  
Secretory Granules ◽  
Succinic Dehydrogenase ◽  
Subcellular Fractions ◽  
Acid Proteinase ◽  
Cell Fractionation ◽  
Ph Optimum ◽  
Pituitary Glands ◽  
The Individual

Fresh anterior pituitary glands from beef and pig were separated by differential centrifugation into subcellular fractions. Nuclei and debris were obtained at 700 g for 15 minutes, secretory granules at 7000 g for 20 minutes, mitochondria at 34,000 g for 15 minutes, and microsomes at 78,000 g for 3 hours. Electron micrographs were taken of the individual fractions. Each fraction was analyzed for nitrogen, pentosenucleic acid (PNA), and phospholipide. Beef and pig anterior lobes were quite similar in their intracellular composition as seen in the subcellular fractions. Succinic dehydrogenase was localized in mitochondria, while alkaline phosphatase was concentrated in the microsomes. A proteinase with pH optimum at 8.2 was exclusively localized. in microsomal and supernatant fractions. Acid phosphatase, acid ribonuclease, and acid proteinase were distributed among the subcellular fractions in another pattern, indicating the presence of a particle type distinct from mitochondria and microsomes. The distribution of cytoplasmic PNA paralleled that of alkaline phosphatase.

scholarly journals Cytochemical staining of the endoplasmic reticulum and glycogen in mouse anterior pituitary cells.

1984 ◽  
Vol 32 (12) ◽  
pp. 1285-1294 ◽  
Author(s):  
A M Cataldo ◽  
R D Broadwell
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Anterior Pituitary ◽  
Cell Types ◽  
Pituitary Cells ◽  
Cytochemical Staining ◽  
Anterior Pituitary Cells ◽  
G6pase Activity ◽  
Pituitary Glands ◽  
Glycogen Particles

The endoplasmic reticulum (ER) and glycogen in secretory cells of anterior pituitary glands from control and fasted mice were investigated ultrastructurally using cytochemical staining techniques. Potential enzyme cytochemical markers for the ER included glucose-6-phosphatase (G6Pase) and nucleoside diphosphatase (NDPase) activities. Presumptive glycogen particles were identified in tissue postfixed in 1% osmium tetroxide-1.5% potassium ferrocyanide or in ultrathin sections poststained with periodic acid-thiocarbohydrazide-silver proteinate. The ER appeared to be related structurally and cytochemically to the nuclear envelope and cis Golgi saccules. Similar relationships between the ER and the trans Golgi saccules or GERL were not observed. In anterior pituitary glands from control mice, G6Pase activity was prominent within the lumen of the ER, nuclear envelope, and cis Golgi saccules of all cells; reaction product was absent in the trans Golgi saccules and in GERL. G6Pase activity was sparse to non-existent in anterior pituitary cells from fasted mice. The cytochemical reaction utilizing the Gomori lead capture method indicated that G6Pase in anterior pituitary cells may function as a phosphohydrolase for converting glucose-6-phosphate to glucose. Cytochemical localization of NDPase activity was not evident in the ER; reaction product was localized consistently in one or two trans Golgi saccules and occasionally in GERL and nascent secretory granules. Presumptive glycogen particles in each of the different secretory cell types from control mice appeared as 20-30 nm wide, electron-dense particles scattered as single entities throughout the cytoplasm. Anterior pituitary glands from fasted mice exhibited conspicuous and numerous clumps of glycogen particles in addition to scattered particles in all cell types except corticotrophs, which appeared to be devoid of glycogen. Glycogen particles were absent in anterior pituitary cells incubated in a medium containing diastase. Our results suggest that in anterior pituitary cells of the mouse: 1) the phosphohydrolytic activity of G6Pase is a reliable cytochemical marker for the ER; 2) the ER is associated morphologically and cytochemically with the cis face but not with the trans face of the Golgi apparatus or with GERL; 3) some glucose-6-phosphate, a possible substrate for G6Pase in vivo, may be derived indirectly from glycogen stores; and 4) modulations in G6Pase activity and glycogen storage during fasting may reflect an alteration in energy metabolism.

The isolation, identification and properties of the hormonal granules of the neurohypophysis

1963 ◽  
Vol 158 (972) ◽  
pp. 388-416 ◽  
Keyword(s):  
Electron Microscopy ◽  
Posterior Pituitary ◽  
Single Fraction ◽  
Pituitary Glands ◽  
Cell Fractions

Methods for the preparation of cell fractions from homogenates of the posterior pituitary glands of rabbits are described. By controlling the speed of centrifugation it was possible to isolate 80% of the oxytocin and vasopressin in a sedimentable form and about half of the total hormones or two-thirds of the sedimentable hormones in a single fraction. Electron microscopy of this fraction showed that it was composed mainly of membrane-bounded granules about 1300 Å in diameter. Similar granules were found in the neural swellings of the rabbit neurohypophysis studied by electron microscopy. The possibility that vasopressin and oxytocin are stored in different granules is discussed.

BIOSYNTHESIS OF GONADOTROPHINS BY RAT PITUITARIES IN VITRO

1975 ◽  
Vol 66 (3) ◽  
pp. 369-374 ◽  
Author(s):  
MRIDULA CHOWDHURY ◽  
EMIL STEINBERGER
Keyword(s):  
Comparative Study ◽  
Anterior Pituitary ◽  
Male Rats ◽  
Leucine Incorporation ◽  
Experimental Conditions ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Endogenous Proteases ◽  
Pituitary Homogenate

SUMMARY A method has been developed for studying biosynthesis of FSH in the rat pituitary in vitro. Anterior pituitary glands were incubated with [3H]leucine; a specific and sensitive immunoprecipitation technique was used to isolate FSH from the pituitary homogenate. Total FSH content of the samples was measured by a double-antibody radioimmunoassay technique. Using this technique, a comparative study of LH and FSH synthesis in the same pituitary of adult male rats incubated for various intervals (0·5–6 h) was done. Increased incorporation of [3H]leucine into both LH and FSH with time was noted. The rate and amount of [3H]leucine incorporation into FSH was found to be higher than that into LH, indicating that either the rate of FSH synthesis is higher than that of LH or FSH has more leucine residues than LH. Greater susceptibility of LH to degradation by endogenous proteases during dialysis may also reflect less incorporation of [3H]leucine into LH. This method provides a reliable tool for evaluating FSH synthesis under various experimental conditions.

Dopamine enters lactotrophs and reaches their secretory granules

1985 ◽  
Vol 104 (1) ◽  
pp. 23-NP ◽  
Author(s):  
M. G. P. Gallardo ◽  
M. Bilinski ◽  
S. R. Chiocchio ◽  
J. H. Tramezzani
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Anterior Pituitary ◽  
Secretory Granules ◽  
Pituitary Cells ◽  
Histochemical Reaction ◽  
Anterior Pituitary Cells ◽  
Biochemical Assays ◽  
Pituitary Lactotroph

ABSTRACT The presence of dopamine in the lactotroph cell, as well as in isolated prolactin secretory granules, was demonstrated by means of an histochemical reaction for electron microscopy. Biochemical assays further confirmed the presence of dopamine in the secretory granules. Autoradiographic preparations examined by light microscopy showed dopamine internalization in dispersed anterior pituitary cells. Isolated anterior pituitary lactotroph cells incorporated more [3H]dopamine than a fraction containing other anterior pituitary cells. J. Endocr. (1985) 104, 23–28

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