scholarly journals Cadmium Mimics Estrogen-Driven Cell Proliferation and Prolactin Secretion from Anterior Pituitary Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e81101 ◽  
Author(s):  
Sonia A. Ronchetti ◽  
Eliana A. Miler ◽  
Beatriz H. Duvilanski ◽  
Jimena P. Cabilla
Keyword(s):  
Cell Proliferation ◽  
Anterior Pituitary ◽  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells

Inhibitory effects of fumagillin and its analogue TNP-470 on the function, morphology and angiogenesis of an oestrogen-induced prolactinoma in Fischer 344 rats

1996 ◽  
Vol 150 (1) ◽  
pp. 99-106 ◽  
Author(s):  
H Stępień ◽  
M Grochal ◽  
K W Zieliński ◽  
S Mucha ◽  
J Kunert-Radek ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Anterior Pituitary ◽  
Angiogenesis Inhibitors ◽  
Prolactin Secretion ◽  
Prolonged Treatment ◽  
Endothelial Cell Proliferation ◽  
Pituitary Cells ◽  
Fischer 344 ◽  
F344 Rats

Abstract The process of angiogenesis occurs in many physiological states, but it is also essential for the growth of solid tumours and metastasis formation. An abnormal arterial vascularization has been shown in prolactin-secreting pituitary adenomas induced by prolonged treatment with oestrogens in Fischer 344 (F344) rats. It is thought that anti-angiogenic agents might be useful in therapy for these tumours. Fumagillin and its analogue TNP-470 are known to inhibit endothelial cell proliferation selectively, but their effect on lactotroph cell secretory function and prolactinoma formation has not yet been described. The aim of the present study was to examine the effects of fumagillin and TNP-470 on prolactin secretion, and morphological and vascular changes within the anterior pituitary in long-term oestrogen-treated male F344 rats in vivo and in vitro. As expected, 7 weeks after s.c. implantation of Silastic tubes containing 10 mg diethylstilboestrol (DES), a very high rise in serum prolactin levels was found. Both angiogenesis inhibitors injected s.c. at doses of 10 mg/kg body weight for 24 days attenuated the stimulatory effect of DES on prolactin production and release. They also diminished prolactin cell density and inhibited cell proliferation expressed as the number of anterior pituitary cells labelled with bromodeoxyuridine (BrdU), but the effect of TNP-470 was minor compared with fumagillin. Both angioinhibitors suppressed neovascularization within the anterior pituitary with similar potency but, on the other hand, they did not affect DES-induced increases in prolactin secretion from cultured rat pituitary cells and cell proliferation in vitro. In conclusion, our results provide strong evidence for the anti-tumour and anti-prolactin activity of angiogenesis inhibitors in the experimentally oestrogen-induced pituitary adenoma; this might be mediated indirectly through the inhibition of angiogenesis. Journal of Endocrinology (1996) 150, 99–106

Bradykinin stimulates phosphoinositide metabolism and prolactin secretion in rat anterior pituitary cells

1989 ◽  
Vol 2 (1) ◽  
pp. 47-53 ◽  
Author(s):  
T.H. Jones ◽  
B. L. Brown ◽  
P. R. M. Dobson
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Inositol Phosphate ◽  
Prolactin Secretion ◽  
Male Rats ◽  
Pituitary Cells ◽  
Phosphoinositide Metabolism ◽  
Phosphate Accumulation ◽  
Anterior Pituitary Cells ◽  
Inositol Phosphate Accumulation

ABSTRACT Bradykinin stimulated prolactin secretion from monolayer cultures of rat anterior pituitary cells, the stimulation being greater from the cells of male rats. This stimulated secretion was accompanied by a rise in total inositol phosphate accumulation, suggesting that the action of bradykinin is mediated by phosphoinositide hydrolysis. The increase in inositol phosphate accumulation was biphasic; a further sharp rise occurred when the concentration of bradykinin exceeded 1 μmol/l. This may indicate that bradykinin acts on other cell types in the pituitary gland. Bradykinin had no effect on growth hormone secretion from cells of normal pituitary glands, or on prolactin secretion and phosphoinositide metabolism in GH3 rat pituitary tumour cells. Bradykinin receptor antagonists (both B1 and B2) had no effect on either bradykinin-stimulated inositol phosphate accumulation or prolactin secretion. Kallikreins, the enzymes responsible for the generation of kinins, are known to be present in the adenohypophysis. Therefore, the results presented here would suggest that kinins may have a role as paracrine agents in the pituitary gland.

Use of a fluorescent dye to measure secretion from intact bovine anterior pituitary cells

1993 ◽  
Vol 13 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Sarah J. V. Stafford ◽  
Spencer L. Shorte ◽  
J. George Schofield
Keyword(s):  
Anterior Pituitary ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Secretory Vesicle ◽  
Prolactin Secretion ◽  
Fluorescent Dye ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Trh Stimulation ◽  
Membrane Changes

The fluorescent dye FM1-43 has been used to indicate membrane changes in individual bovine anterior pituitary cells exposed to secretory stimuli. After ten minutes incubation with FM1-43 (2 μM), cells showed three patterns of dye fluorescence: annular, partly filled and uniformly filled. FM1-43 fluorescence was increased in 61% of the cells by TRH (40 nM), a physiological stimulus for prolactin secretion, and in 89% of the cells by 60 mM external K+. The fluorescence also increased when cells incubated in the presence of quinpirole, a dopamine D2-receptor agonist which inhibits prolactin secretion, were exposed to raclopride, a D-2 antagonist. The increases in FM1-43 fluorescence caused by these treatments suggests that the dye acts as an indicator of secretion, possibly through incorporation into secretory vesicle membranes exposed on the cell surface during exocytosis. If the dye was washed away after loading, the fluorescence of partly and uniformly filled cells was retained and a rise in fluorescence could still be seen on stimulation by TRH. This suggests that some dye had been taken up by endocytosis and trapped in an intracellular compartment, which expanded through membrane recapture after TRH stimulation. FM1-43 could therefore be a useful probe for membrane cycling associated with secretory responses.

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