Prolactin content in rat pituitary gland. RIA of prolactin after different extraction procedures

1981 ◽  
Vol 97 (3) ◽  
pp. 338-342 ◽  
Author(s):  
E. Haggi ◽  
A. Aoki
Keyword(s):  
Electron Microscopy ◽  
Pituitary Gland ◽  
Secretory Granules ◽  
Freezing And Thawing ◽  
Extraction Procedures ◽  
Standard Procedures ◽  
Rat Pituitary ◽  
Complete Extraction ◽  
Prolactin Content ◽  
Triton X

Abstract. The prolactin content of rat pituitary varies considerably when determined by RIA, due to incomplete solubilization of prolactin secretory granules with standard procedures for tissue homogenization and centrifugation. Freezing and thawing, Triton X-100 and ultrasonic treatments increased the yield of prolactin significantly but electron microscopy of pellets revealed numerous unmodified secretory granules. Addition of 2.5 m urea produced complete extraction of tissue prolactin confirmed by RIA of supernatants and electron microscopy of pellets.

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.

Regression of redundant lactotrophs in rat pituitary gland after cessation of lactation

1986 ◽  
Vol 111 (3) ◽  
pp. 367-NP ◽  
Author(s):  
E. S. Haggi ◽  
A. I. Torres ◽  
C. A. Maldonado ◽  
A. Aoki
Keyword(s):  
Pituitary Gland ◽  
Cell Count ◽  
Morphometric Analysis ◽  
Morphological Changes ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Prolactin Content ◽  
Prolactin Synthesis ◽  
Regressive Changes

ABSTRACT Regressive changes occurring in the pituitary gland of the rat after removal of litters were studied. Pituitary glands of lactating rats were characterized by the presence of numerous hypertrophied lactotrophs. Interruption of lactation caused a blockade of prolactin synthesis and secretion, followed by degeneration of lactotrophs. Morphometric analysis of pituitary glands revealed that lactotrophs accounted for about 50% of the total hypophysial cell count in lactating rats. This percentage decreased progressively and reached pre-pregnant levels 7 days after removal of litters; the decrease was inversely correlated with an increase in the number of degenerating lactotrophs which comprised 30% of all lactotrophs 72 h after removal of litters. The morphological changes found in lactotrophs were closely related to changes in the prolactin content of serum and the pituitary gland. Regression of lactotrophs appeared to be the most important cause inducing the reversal of hypophysial lactotrophic activity to pre-pregnant conditions. J. Endocr. (1986) 111, 367–373

scholarly journals Neuroserpin is expressed in the pituitary and adrenal glands and induces the extension of neurite-like processes in AtT-20 cells

2000 ◽  
Vol 345 (3) ◽  
pp. 595-601 ◽  
Author(s):  
Rena M. HILL ◽  
Parmjeet K. PARMAR ◽  
Leigh C. COATES ◽  
Eva MEZEY ◽  
John F. PEARSON ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Serine Protease ◽  
Plasminogen Activator ◽  
Secretory Granules ◽  
Stable Cell Line ◽  
Rat Pituitary ◽  
Zymographic Analysis ◽  
Conditioned Culture Medium ◽  
Extracellular Matrix Interactions

Two cDNAs encoding the serine protease inhibitor (serpin) neuroserpin were cloned from a rat pituitary cDNA library (rNS-1, 2922 bp; rNS-2, 1599 bp). In situ hybridization histochemistry showed neuroserpin transcripts in the intermediate, anterior and posterior lobes of the pituitary gland and medullary cells in the adrenal gland. Expression of rNS-1 mRNA was restricted to selected cells in the pituitary gland. Analysis of purified secretory-granule fractions from pituitary and adrenal tissues indicated that neuroserpin was found in dense-cored secretory granules. This result suggested that endocrine neuroserpin may regulate intragranular proteases or inhibit enzymes following regulated secretion. To investigate the function of neuroserpin in endocrine tissues we established stable anterior pituitary AtT-20 cell lines expressing neuroserpin. Cells with increased levels of neuroserpin responded by extending neurite-like processes. Extracellular proteolysis by serine protease plasminogen activators has been suggested to regulate neurite outgrowth. As neuroserpin inhibits tissue plasminogen activator (tPA) in vitro, we measured plasminogen-activator levels. Zymographic analysis indicated that AtT-20 cells synthesized and secreted a plasminogen activator identical in size to tPA. A higher-molecular-mass tPA-neuroserpin complex was also observed in AtT-20-cell conditioned culture medium. tPA levels were similar in parent AtT-20 cells and a stable cell line with increased levels of neuroserpin. There was no accumulation of a tPA-neuroserpin complex. Together these results identify endocrine cells as an important source of neuroserpin. Moreover they suggest that neuroserpin is released from dense-cored secretory granules to regulate cell-extracellular matrix interactions through a mechanism that may not directly involve tPA.

AN ELECTRON MICROSCOPIC STUDY OF NORMAL AND NEOPLASTIC ACIDOPHIL CELLS OF THE RAT PITUITARY

1971 ◽  
Vol 67 (1) ◽  
pp. 29-39 ◽  
Author(s):  
U. Schelin ◽  
P. M. Lundin
Keyword(s):  
Electron Microscopy ◽  
Secretory Granules ◽  
Female Rats ◽  
Male Rats ◽  
Cell Type ◽  
Prolactin Cells ◽  
Electron Microscopic ◽  
Gh Cells ◽  
Rat Pituitary ◽  
Close Relationship

ABSTRACT The morphology of normal and neoplastic acidophil cells of the rat pituitary has been studied by electron microscopy with special reference to the size and shape of the secretory granules. In the female rats, pregnant or non-pregnant, growth hormone (GH) cells and prolactin cells are easily separated, but in the male rats this separation is very uncertain. Acidophil tumours with granules similar to the GH type or to the prolactin type can be induced with stilboestrol treatment. These results indicate a close relationship between the two types of acidophil cells. They may be derived from a common progenitor which can be differentiated into either GH or prolactin cell or they may represent one cell type capable of producing both hormones.

Evidence for direct action of calcitonin in the rat pituitary gland

1989 ◽  
Vol 120 (5) ◽  
pp. 682-688 ◽  
Author(s):  
G. Morel ◽  
J.-G. Chabot ◽  
A. Enjalbert ◽  
M. Priam ◽  
P. M. Dubois
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Direct Action ◽  
Secretory Granules ◽  
In Vitro Study ◽  
Male Rat ◽  
Pituitary Cells ◽  
Cytoplasmic Matrix ◽  
Rat Pituitary

Abstract. Classic concepts of calcitonin (CT) function have focused on the effects of CT on calcium homeostasis. More recently CT actions on brain and pituitary have been investigated. In order to evaluate the effects of CT on the anterior pituitary gland we studied the action(s) of CT in vitro and visualized endogenous CT in adult male rat pituitary gland by immunocytochemistry on ultrathin sections obtained by cryoultramicomy. In vitro study using dispersed anterior pituitary cells indicated that CT stimulated the secretion of PRL, whereas the secretion of GH, TSH and LH was not affected. CT-like immunoreactivity was observed in lactotropes only. The other pituitary cell types were not immunoreactive. In lactotropes, immunostaining was observed in the cytoplasm and in the nucleus. In the cytoplasm, CT-like immunoreactivity was visuzalized in the cytoplasmic matrix and in the secretory granules. In the nucleus, immunostaining was distributed primarly in the euchromatin, in the vincinity of heterochromatin region. CT-like immunoreactivity was also observed at the plasma membrane but was only scarce. No reaction product was found when anti-CT serum pre-incubated with CT was used. In conclusion, these results bring evidence for a direct action of CT on lactotrope regulation in vitro as well as in intact animals.

scholarly journals Immunocytochemical Localization of Secretogranin III in the Anterior Lobe of Male Rat Pituitary Glands

2003 ◽  
Vol 51 (2) ◽  
pp. 227-238 ◽  
Author(s):  
Yuko Sakai ◽  
Masahiro Hosaka ◽  
Yoshiki Hira ◽  
Tatsuo Harumi ◽  
Yoshiyuki Ohsawa ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Secretory Granule ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Anterior Lobe ◽  
Male Rat ◽  
Secretory Proteins ◽  
Chromogranin B ◽  
Rat Pituitary ◽  
Granule Membrane

Secretogranin III (SgIII) is one of the acidic secretory proteins, designated as granins, which are specifically expressed in neuronal and endocrine cells. To clarify its precise distribution in the anterior lobe of the rat pituitary gland, we raised a polyclonal antiserum against rat SgIII for immunocytochemical analyses. By immunohistochemistry using semithin sections, positive signals for SgIII were detected intensely in mammotropes and thyrotropes, moderately in gonadotropes and corticotropes, but not in somatotropes. The distribution pattern of SgIII in the pituitary gland was similar to that of chromogranin B (CgB), also of the granin protein family, suggesting that the expressions of these two granins are regulated by common mechanisms. The localization of SgIII in endocrine cells was confirmed by immunoelectron microscopy. In particular, secretory granules of mammotropes and thyrotropes were densely and preferentially co-labeled for SgIII and CgB in their periphery. Moreover, positive signals for SgIII were occasionally found in cells containing both prolactin and TSH in secretory granules. These lines of evidence suggest that SgIII and CgB are closely associated with the secretory granule membrane and that this membrane association might contribute to gathering and anchoring of other soluble constituents to the secretory granule membrane.

Isolation of two different pools of pituitary prolactin

1984 ◽  
Vol 107 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Alicia I. Torres ◽  
Ernesto S. Haggi ◽  
Agustín Aoki
Keyword(s):  
Electron Microscopy ◽  
Pituitary Gland ◽  
Soluble Fraction ◽  
Secretory Granules ◽  
The Other ◽  
Pituitary Prolactin

Abstract. Two pools of prolactin (Prl) were isolated from the pituitary gland. One readily soluble after homogenization and the other sedimented with secretory granules. In ovariectomized-oestrogen treated rats the latter represents the major Prl fraction of pituitary and can be recovered as immunoreactive Prl after extraction in 2.5 m urea. By correlation of electron microscopy, chromatography and RIA, evidence is gathered that the soluble fraction is constituted by monomeric (little) Prl and that secretory granules contain Prl in a polymerized form (big).

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