Membrane-associated forms of peptidylglycine alpha-amidating monooxygenase activity in rat pituitary. Tissue specificity.

Abstract Our recent studies on rat pituitary tissue suggest that the annexin I-dependent inhibitory actions of glucocorticoids may not be exerted directly on endocrine cells but indirectly via folliculo-stellate (FS) cells. FS cells contain glucocorticoid receptors and abundant annexin I. We have studied the localization of annexin I in FS cells and the ability of dexamethasone to induce annexin I secretion by an FS (TtT/GF) cell line, using Western blotting and immunofluorescence microscopy. Exposure of TtT/GF cells to dexamethasone (0.1 μm, 3 h) caused an increase in the amount of annexin I protein in the intracellular compartment and attached to the surface of the cells. In nonpermeabilized cells, immunofluorescence labeling revealed that annexin I immunoreactivity was associated with the cell surface and concentrated in focal patches on the ends of cytoplasmic processes; dexamethasone (0.1 μm, 3 h) increased both the number and intensity of these foci. Immunogold electron microscopy confirmed in anterior pituitary tissue the presence of immunoreactive-annexin at the surface of FS cell processes contacting endocrine cells. These data support our hypothesis that annexin I is released by FS cells in response to glucocorticoids to mediate glucocorticoid inhibitory actions on pituitary hormone release via a juxtacrine mechanism.

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Effect of Growth Hormone-Releasing Factor-44 upon Release of Concurrently Synthesized Hormone by Perifused Rat Pituitary Tissue*

Endocrinology ◽

10.1210/endo-119-3-1245 ◽

1986 ◽

Vol 119 (3) ◽

pp. 1245-1253 ◽

Cited By ~ 8

Author(s):

MAX E. STACHURA ◽

JEAN M. TYLER ◽

PATRICIA G. KENT

Keyword(s):

Growth Hormone ◽

Growth Hormone Releasing Factor ◽

Pituitary Tissue ◽

Rat Pituitary

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Bradykinin-Induced ACTH Release from Rat Pituitary Tissue in vitro

Neuroendocrinology ◽

10.1159/000124548 ◽

1986 ◽

Vol 43 (3) ◽

pp. 336-339 ◽

Cited By ~ 6

Author(s):

Taiichiro Okajima ◽

Georg Hertting

Keyword(s):

Pituitary Tissue ◽

Rat Pituitary ◽

Acth Release

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Specificity of gonadotrophin-releasing hormone binding sites of the human corpus luteum: comparison with receptors of rat pituitary gland

Journal of Endocrinology ◽

10.1677/joe.0.1080323 ◽

1986 ◽

Vol 108 (3) ◽

pp. 323-328 ◽

Cited By ~ 22

Author(s):

T. A. Bramley ◽

G. S. Menzies ◽

D. T. Baird

Keyword(s):

Corpus Luteum ◽

Binding Sites ◽

Specific Binding ◽

Similar Degree ◽

Releasing Hormone ◽

Pituitary Tissue ◽

Rat Pituitary ◽

Luteal Tissue ◽

Gonadotrophin Releasing Hormone ◽

Human Corpus Luteum

ABSTRACT The effects of a number of analogues of gonadotrophin-releasing hormone (GnRH) on the binding of a radiolabelled GnRH agonist (GnRH-A; d-Ser(But)6, des Gly10]GnRH-ethylamide) to homogenates of human corpus luteum (CL) and rat pituitary tissue were compared. Specific binding was inhibited by GnRH and GnRH-like peptides only. Both the C-terminal amide and N-terminal region of the GnRH molecule were required for binding in both tissues. However, amino acid substitutions at position 6 markedly enhanced, and at position 8 markedly reduced, binding potencies in rat pituitary tissue compared with human CL binding sites. These results indicate that GnRH-binding sites of rat pituitary and human luteal tissue have a similar degree of specificity for GnRH-like peptides, and a similar requirement for both N- and C-terminal regions of the peptide, but that differences in specificity related to the mid-chain region of GnRH exist between human luteal and rat pituitary binding sites. J. Endocr. (1985) 000, 000–000

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SALMONID MELANIN-CONCENTRATING HORMONE INHIBITS CORTICOTROPHIN RELEASE

Journal of Endocrinology ◽

10.1677/joe.0.106r005 ◽

1985 ◽

Vol 106 (2) ◽

pp. R5-R8 ◽

Cited By ~ 83

Author(s):

B.I. Baker ◽

D.J. Bird ◽

J.C. Buckingham

Keyword(s):

In Vitro Release ◽

Colour Change ◽

Acth Secretion ◽

Pituitary Tissue ◽

Rat Pituitary ◽

Melanin Concentrating Hormone ◽

Vitro Release

ABSTRACT Melanin-concentrating hormone (MCH) is a neural peptide associated with colour change in fishes. We show here that it also inhibits corticotrophin (ACTH) secretion. Synthetic salmonid MCH at a concentration of 100 pmol/l reduced the in-vitro release of ACTH by pars distales (pDs) taken from stressed trout. At lower concentrations (10 pmol/l) the peptide inhibited CRF-41-induced secretion of ACTH by pDs removed from unstressed trout, while at higher concentrations (10 nmol/l) it reduced the corticotrophic response of rat pituitary tissue to CRF-41.

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ABSENCE OF AN IMMUNOLOGICALLY DISTINCT FOLLICLE-STIMULATING HORMONE RELEASING FACTOR IN RAT STALK MEDIAN EMINENCE EXTRACTS

Journal of Endocrinology ◽

10.1677/joe.0.0680089 ◽

1976 ◽

Vol 68 (1) ◽

pp. 89-94 ◽

Cited By ~ 3

Author(s):

M. SHAHMANESH ◽

S. L. JEFFCOATE

Keyword(s):

Median Eminence ◽

Male Rats ◽

Rabbit Serum ◽

Normal Rabbit Serum ◽

Pituitary Tissue ◽

Rat Pituitary ◽

Pre Treatment ◽

Lh Rh ◽

Dose Levels

SUMMARY Rat stalk median eminence (SME) extract was incubated with various quantities of an antiserum raised against synthetic luteinizing hormone releasing hormone (LH-RH) and the resulting material was used at two or more dose levels to stimulate release of LH and FSH from anterior pituitary tissue, obtained from male rats, incubated in vitro. The resulting dose–response lines were used to obtain the LH- and FSH-releasing potency of the material, expressed as a percentage of SME extract pre-incubated with normal rabbit serum. Treatment with various doses of antiserum reduced LH-releasing and FSH-releasing potencies to a similar extent. Stalk median eminence extract and synthetic LH-RH were incubated with antiserum and directly compared in the same experiment in vitro. The changes in LH and FSH release caused by pre-treatment with antibody were similar for SME extract and synthetic LH-RH. In a final experiment, SME extract was passed through a column of Sepharose 2B particles to which was coupled anti-LH-RH antibody. The resulting material, when mixed with synthetic LH-RH and used to stimulate rat pituitary tissue in vitro caused a similar increase in the LH- and FSH-releasing potencies of the synthetic decapeptide. It is concluded that rat SME extract contains a single releasing factor for LH and FSH immunologically indistinguishable from synthetic LH-RH.

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FUNCTIONAL AND MORPHOLOGICAL OBSERVATIONS ON THE RAT PITUITARY GRAFTED INTO THE ANTERIOR CHAMBER OF THE EYE

Journal of Endocrinology ◽

10.1677/joe.0.0190164 ◽

1959 ◽

Vol 19 (2) ◽

pp. 164-173 ◽

Cited By ~ 24

Author(s):

L. MARTINI ◽

A. DE POLI ◽

A. PECILE ◽

S. SAITO ◽

F. TANI

Keyword(s):

Anterior Chamber ◽

Median Eminence ◽

Anterior Pituitary ◽

Sella Turcica ◽

Adrenal Weight ◽

Acth Secretion ◽

Pituitary Tissue ◽

Lysine Vasopressin ◽

Rat Pituitary ◽

Hypophysectomized Rats

SUMMARY It is shown that anterior pituitary tissue grafted into hypophysectomized rats and lacking any connexion with the median eminence does not retain any somatotrophic or gonadotrophic activities, but has some adrenocorticotrophic (ACTH) and thyrotrophic (TSH) activities. This conclusion is based on: (1) the partial maintenance of thyroid and adrenal weight; (2) the results of studies on 131I uptake and on TSH concentration in the grafted pituitaries; (3) the persistence of significant adrenocorticotrophic responses to Pitressin, lysine-vasopressin and Guillemin's fraction D; (4) the presence of histological and histochemical signs of activity in the grafted gland. The subnormal levels of secretion observed in the pituitary grafted into sites far removed from the sella turcica, seem to depend on the lack of some neurohumoral stimulus which normally activates the intact pituitary via the hypophysio-portal vessels. Evidence is given that vasopressin may be the hypothalamic neurohumor involved in ACTH secretion, and that the ACTH-releasing activity of Guillemin's fraction D may be accounted for by its vasopressin content.

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