scholarly journals Effects of Vasopressin V1b Receptor Deficiency on Adrenocorticotropin Release from Anterior Pituitary Cells in Response to Oxytocin Stimulation

Endocrinology ◽  
2008 ◽  
Vol 149 (10) ◽  
pp. 4883-4891 ◽  
Author(s):  
Kazuaki Nakamura ◽  
Yoko Fujiwara ◽  
Reiko Mizutani ◽  
Atsushi Sanbe ◽  
Noriko Miyauchi ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Receptor Antagonist ◽  
Anterior Pituitary ◽  
Primary Cultures ◽  
Control Level ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
V1b Receptor ◽  
Rat Pituitary ◽  
Acth Release

Oxytocin (OT) is one of the secretagogues for stress-induced ACTH release. OT-induced ACTH release is reported to be mediated by the vasopressin V1b receptor in the rat pituitary gland, which contains both OT and V1b receptors. We examined OT-induced ACTH release using primary cultures of anterior pituitary cells from wild-type (V1bR+/+) and V1b receptor knockout (V1bR−/−) mice. OT stimulated similar levels of ACTH release from pituitary cells of V1bR+/+ and V1bR−/− mice. OT-induced ACTH release was significantly inhibited by the selective V1b receptor antagonist SSR149415 and the OT receptor antagonist CL-14-26 in V1bR+/+ mice. In addition, cotreatment with SSR149415 at 10−6m and CL-14-26 at 10−6m inhibited OT-induced ACTH release to the control level inV1bR+/+ mice. In V1bR−/− mice, OT-induced ACTH release was significantly inhibited by CL-14-26 at 10−8m and completely inhibited at 10−7m. These results indicate that OT induces the ACTH response via OT and V1b receptors inV1bR+/+ mice but via only OT receptors in V1bR−/− mice. The gene expression level of the OT receptor was significantly higher in the anterior pituitary gland of V1bR−/− mice than in that of V1bR+/+ mice, suggesting that the OT receptor is up-regulated to compensate for ACTH release under conditions of V1b receptor deficiency.

scholarly journals Prolactin receptor antagonism in mouse anterior pituitary: effects on cell turnover and prolactin receptor expression

2012 ◽  
Vol 302 (3) ◽  
pp. E356-E364 ◽  
Author(s):  
Jimena Ferraris ◽  
Florence Boutillon ◽  
Marie Bernadet ◽  
Adriana Seilicovich ◽  
Vincent Goffin ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Pituitary Gland ◽  
Receptor Antagonist ◽  
Anterior Pituitary ◽  
Prolactin Receptor ◽  
Receptor Expression ◽  
Brdu Incorporation ◽  
Pituitary Cells ◽  
Cell Turnover ◽  
Anterior Pituitary Cells

Since anterior pituitary expresses prolactin receptors, prolactin secreted by lactotropes could exert autocrine or paracrine actions on anterior pituitary cells. In fact, it has been observed that prolactin inhibits its own expression by lactotropes. Our hypothesis is that prolactin participates in the control of anterior pituitary cell turnover. In the present study, we explored the action of prolactin on proliferation and apoptosis of anterior pituitary cells and its effect on the expression of the prolactin receptor. To determine the activity of endogenous prolactin, we evaluated the effect of the competitive prolactin receptor antagonist Δ1–9-G129R-hPRL in vivo, using transgenic mice that constitutively and systemically express this antagonist. The weight of the pituitary gland and the anterior pituitary proliferation index, determined by BrdU incorporation, were higher in transgenic mice expressing the antagonist than in wild-type littermates. In addition, blockade of prolactin receptor in vitro by Δ1–9-G129R-hPRL increased proliferation and inhibited apoptosis of somatolactotrope GH3 cells and of primary cultures of male rat anterior pituitary cells, including lactotropes. These results suggest that prolactin acts as an autocrine/paracrine antiproliferative and proapoptotic factor in the anterior pituitary gland. In addition, anterior pituitary expression of the long isoform of the prolactin receptor, measured by real-time PCR, increased about 10-fold in transgenic mice expressing the prolactin receptor antagonist, whereas only a modest increase in the S3 short-isoform expression was observed. These results suggest that endogenous prolactin may regulate its own biological actions in the anterior pituitary by inhibiting the expression of the long isoform of the prolactin receptor. In conclusion, our observations suggest that prolactin is involved in the maintenance of physiological cell renewal in the anterior pituitary. Alterations in this physiological role of prolactin could contribute to pituitary tumor development.

Interleukin 6 possibly induced by interleukin 1β in the pituitary gland stimulates the release of gonadotropins and prolactin

1990 ◽  
Vol 122 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Masaaki Yamaguchi ◽  
Noboru Matsuzaki ◽  
Kenji Hirota ◽  
Akira Miyake ◽  
Osamu Tanizawa
Keyword(s):  
Pituitary Gland ◽  
Interleukin 6 ◽  
Anterior Pituitary ◽  
Interleukin 1 ◽  
Interleukin 1Β ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

Abstract The abilities of recombinant human interleukin 1 (IL-1) and IL-6 to induce release of FSH, LH and PRL from rat pituitary cells in vitro were examined. IL-1 and IL-6 induced significant releases of FSH, LH and PRL within 3 h. The extents of release of these compounds induced by IL-1 and IL-6 were similar to those induced by GnRH and TRH. Rat anterior pituitary cells released IL-6 spontaneously, and its release was enhanced by IL-1β. This effect of IL-1β was inhibited significantly by a rabbit anti-IL-1β antiserum. These findings suggest that IL-1 induced the release of IL-6 from rat pituitary, and that the released IL-6 stimulated the secretions of FSH, LH and PRL.

Regulation of ACTH secretory pathways in cultured pituitary cells

1991 ◽  
Vol 261 (5) ◽  
pp. C793-C798 ◽  
Author(s):  
J. Schwartz ◽  
S. Gibson ◽  
A. White
Keyword(s):  
Anterior Pituitary ◽  
Adrenocorticotropic Hormone ◽  
Corticotropin Releasing Factor ◽  
Pituitary Cells ◽  
Receptor Complex ◽  
Response Mechanism ◽  
Acth Secretion ◽  
Secretory Pathways ◽  
Anterior Pituitary Cells ◽  
Acth Release

Although chloroquine, an agent that disrupts regulated protein secretion, has previously been shown to decrease the adrenocorticotropic hormone (ACTH) secretory response to adenosine 3',5'-cyclic monophosphate or corticotropin-releasing factor (CRF) in AtT-20 and rat anterior pituitary cells, respectively, it has no effect on the response to vasopressin. The present study extended experiments with chloroquine to cultured sheep anterior pituitary cells, which have a greater maximum response to vasopressin. Chloroquine (200 microM) had no effect on basal ACTH secretion or on stimulation by vasopressin. In contrast to the rat, the net response to CRF was tripled by chloroquine in ovine cells. The effect of chloroquine on the response to CRF was more effective by coexposure of cells to CRF and chloroquine than by pretreatment with chloroquine. Monensin or vinblastine did not increase the ACTH response to CRF. The results indicate ACTH release in response to vasopressin is chloroquine insensitive in this way, can be dissociated from the mechanism that responds to CRF, and would be consistent with the CRF response mechanism involving pathways that can alter the secretory pool of ACTH. When chloroquine acts to increase the response to CRF, it is likely not to act by stabilizing the CRF-receptor complex.

Blockage of K+ channels reverses the inhibitory action of atriopeptin on secretagogue-stimulated ACTH release by perifused isolated rat anterior pituitary cells

1990 ◽  
Vol 126 (2) ◽  
pp. 183-191 ◽  
Author(s):  
F. A. Antoni ◽  
G. Dayanithi
Keyword(s):  
Anterior Pituitary ◽  
Inhibitory Action ◽  
Calcium Ionophore ◽  
Delayed Rectifier ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Acth Secretion ◽  
Anterior Pituitary Cells ◽  
Isolated Rat ◽  
Acth Release

ABSTRACT The aim of the present study was to investigate how atriopeptin inhibits secretagogue-stimulated ACTH secretion in vitro. Perifused isolated rat anterior pituitary cells were used throughout; the ACTH content of the perifusate was measured by radioimmunoassy. In the presence of a constant (0·05 nmol/l) concentration of 41-residue corticotrophin-releasing factor (CRF), arginine vasopressin (AVP; 0·05–50 nmol/l) stimulated ACTH secretion in a concentration-dependent manner, the combination of 0·05 nmol CRF/l and 0·5 nmol AVP/l (CRF/AVP) stimulated ACTH release to six- to eightfold above baseline. The effect of CRF/AVP was not modified by tetrodotoxin, but was abolished by CoCl2 and reduced to about 70% of the control stimulus by nifedipine. Application of 103–126 residue atriopeptin for 10 min before and 2·5 min during the CRF/AVP stimulus strongly suppressed the evoked release of ACTH, the maximal inhibition was 75–90% at 10 nmol atriopeptin/l. The calcium ionophore ionomycin (200 nmol/l) reversed the effect of atriopeptin while it had no secretagogue activity of its own, and did not enhance the response to CRF/AVP. A variety of blockers of K+ channels, 4-amino pyridine, tetraethylammonium, apamine, quinine, but not tolbutamide, effectively antagonized the inhibitory action of atriopeptin (10 nmol/l). None of these drugs altered ACTH release evoked by CRF/AVP. In concentration–response experiments, the half effective concentration of 4-aminopyridine and tetraethyl-ammonium were around 1 mmol/l and 10 nmol/l for apamine. Finally, tetraethylammonium and apamine also antagonized the inhibition of CRF/AVP-evoked ACTH release by 8-Br-cGMP. These data suggest that (1) at least two types of K+ channels, a delayed rectifier and the apamine-sensitive Ca2+-activated channel, are functionally important in pituitary corticotroph cells; (2) atriopeptin inhibits CRF/AVP-stimulated ACTH secretion by hyperpolarizing the plasma membrane and thus reducing the uptake of Ca2+ into the cells; (3) cGMP is the intracellular mediator of the action of atriopeptin on corticotroph cells. Journal of Endocrinology (1990) 126, 183–191

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.

Estrogens exert a rapid apoptotic action in anterior pituitary cells

2009 ◽  
Vol 296 (4) ◽  
pp. E664-E671 ◽  
Author(s):  
S. Zárate ◽  
G. Jaita ◽  
V. Zaldivar ◽  
D. B. Radl ◽  
G. Eijo ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Primary Cultures ◽  
Ovariectomized Rats ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Steroid Signaling ◽  
A Cell ◽  
17Β Estradiol ◽  
Induced Apoptosis ◽  
Classical Mechanism

It is now accepted that estrogens not only stimulate lactotrope proliferation but also sensitize anterior pituitary cells to proapoptotic stimuli. In addition to their classical mechanism of action through binding to intracellular estrogen receptors (ERs), there is increasing evidence that estrogens exert rapid actions mediated by cell membrane-localized ERs (mERs). In the present study, we examined the involvement of membrane-initiated steroid signaling in the proapoptotic action of estradiol in primary cultures of anterior pituitary cells from ovariectomized rats by using estren, a synthetic estrogen with no effect on classical transcription and a cell-impermeable 17β-estradiol conjugate (E2-BSA). Both compounds induced cell death of anterior pituitary cells after 60 min of incubation as assessed by flow cytometry and the [3-(4,5-dimethylthiazol-2-yl)]-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Estren, E2, and E2-BSA induced apoptosis of lactotropes and somatotropes as evaluated by the deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay and immunodetection of prolactin (PRL) and growth hormone (GH). The proapoptotic effect of E2-BSA was abrogated by ICI-182,780, an antagonist of ERs. The expression of membrane-associated ERα was observed in PRL- and GH-bearing cells. Our results indicate that estradiol is able to exert a rapid apoptotic action in anterior pituitary cells, especially lactotropes and somatotropes, by a mechanism triggered by mERs. This mechanism could be involved in anterior pituitary cell turnover.

GROWTH IN MONOLAYER CULTURE OF RAT PITUITARY CELLS WHICH SYNTHETIZE AND RELEASE ACTH

1975 ◽  
Vol 79 (3) ◽  
pp. 421-430 ◽  
Author(s):  
R. E. Lang ◽  
I. Hilwig ◽  
K. H. Voigt ◽  
H. L. Fehm ◽  
E. F. Pfeiffer
Keyword(s):  
Pituitary Gland ◽  
Monolayer Culture ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Antibody Technique ◽  
Gland Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells ◽  
Dose Dependent ◽  
Acth Release

ABSTRACT Cultures of rat pituitary gland cells were developed to study biosynthesis and release of ACTH. ACTH measurement was accomplished by radioimmunoassay. ACTH release was observed following stimulation with theophylline and cAMP in a dose-dependent manner. Biosynthesis was demonstrated by incorporation of 3H-phenylalanine into the hormone, employing a double antibody technique.

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