Involvement of SNAP-25 in TRH-induced exocytosis in pituitary GH4C1 cells

1997 ◽  
Vol 153 (1) ◽  
pp. R5-R10 ◽  
Author(s):  
N Masumoto ◽  
Y Ikebuchi ◽  
T Matsuoka ◽  
K Tasaka ◽  
A Miyake ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Immunoblot Analysis ◽  
Synaptic Membrane ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Rt Pcr ◽  
Immunofluorescence Analysis ◽  
Prolactin Release ◽  
Regulated Exocytosis

Abstract The synaptic membrane protein synaptosomal-associated protein (SNAP-25) has recently been implicated as one of the key proteins involved in exocytotic membrane fusion in neurons. However, the role of SNAP-25 in pituitary hormone release is not known. In this study, we determined that SNAP-25 is involved in regulated exocytosis in the clonal pituitary cell line GH4C1. SNAP-25 messenger RNA and protein were detected in GH4C1 cells by RT-PCR and immunoblot analysis, respectively. Immunofluorescence analysis indicated that SNAP-25 protein was localized in the plasma membrane. Next, to determine the function of SNAP-25 in GH4C1 cells, specific inhibitors of SNAP-25, botulinum neurotoxin (BoNT) /A or /E, and antisense SNAP-25 oligonucleotide were used. Neither BoNT/A nor BoNT/E affected thyrotropin-releasing hormone (TRH)-induced cytosolic Ca2+ increase, but both inhibited TRH-induced exocytosis. Moreover, they dose-dependently inhibited TRH-induced prolactin release. The introduction of antisense oligonucleotide into the cells also inhibited TRH-induced prolactin release. These results suggest that SNAP-25 is involved in regulated exocytosis in GH4C1 cells.

Investigate the role of GPR15/BOB in the SLE patients

2018 ◽  
Vol 6 (1) ◽  
pp. 19-32
Author(s):  
Caroline G. Jackson ◽  
Donald R. Kwan
Keyword(s):  
Peripheral Blood ◽  
Messenger Rna ◽  
Viral Envelope ◽  
Orphan Receptor ◽  
Blood Monocytes ◽  
Rt Pcr ◽  
Peripheral Blood Monocytes ◽  
Healthy Donors ◽  
Hiv 1

GPR15 functions as a cellular co-receptor for some isolates of HIV-1, HIV-2, and SIV through interactions with several viral envelope proteins. The objective of this study was to investigate the expression of orphan receptor GPR15/BOB in the serum of SLE patients and non-SLE healthy people. GPR15/BOB expression was analysed by flow cytometry while, GPR15/BOB messenger RNA was examined in peripheral blood monocytes by RT-PCR. GPR15/BOB mRNA was detected in all periphral blood of SLE patients examined. Further, a significant increase in GPR15/BOB expression as measured by mean fluorescence intensity was observed on SLE PB neutrophils compared to these cell populations from healthy donors. We concluded that GPR15/BOB is expressed in monocytes and neutrophils in peripheral blood, and expression is up-regulated in SLE patients compared to controls. GPR15/BOB may play a role in SLE pathogenesis.

scholarly journals Growth hormone-releasing peptide-2 infusion synchronizes growth hormone, thyrotrophin and prolactin release in prolonged critical illness

1999 ◽  
pp. 17-22 ◽  
Author(s):  
G Van den Berghe ◽  
P Wouters ◽  
CY Bowers ◽  
F de Zegher ◽  
R Bouillon ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Critical Illness ◽  
Cross Correlation ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Prolactin Release ◽  
Anterior Pituitary Hormone ◽  
Temporal Coupling ◽  
Pituitary Secretion ◽  
Design And Methods

OBJECTIVE: During prolonged critical illness, nocturnal pulsatile secretion of GH, TSH and prolactin (PRL) is uniformly reduced but remains responsive to the continuous infusion of GH secretagogues and TRH. Whether such (pertinent) secretagogues would synchronize pituitary secretion of GH, TSH and/or PRL is not known. DESIGN AND METHODS: We explored temporal coupling among GH, TSH and PRL release by calculating cross-correlation among GH, TSH and PRL serum concentration profiles in 86 time series obtained from prolonged critically ill patients by nocturnal blood sampling every 20 min for 9 h during 21-h infusions of either placebo (n=22), GHRH (1 microg/kg/h; n=10), GH-releasing peptide-2 (GHRP-2; 1 microg/kg/h; n=28), TRH (1 microg/kg/h; n=8) or combinations of these agonists (n=8). RESULTS: The normal synchrony among GH, TSH and PRL was absent during placebo delivery. Infusion of GHRP-2, but not GHRH or TRH, markedly synchronized serum profiles of GH, TSH and PRL (all P< or =0.007). After addition of GHRH and TRH to the infusion of GHRP-2, only the synchrony between GH and PRL was maintained (P=0.003 for GHRH + GHRP-2 and P=0.006 for TRH + GHRH + GHRP-2), and was more marked than with GHRP-2 infusion alone (P=0.0006 by ANOVA). CONCLUSIONS: The nocturnal GH, TSH and PRL secretory patterns during prolonged critical illness are herewith further characterized to include loss of synchrony among GH, TSH and PRL release. The synchronizing effect of an exogenous GHRP-2 drive, but not of GHRH or TRH, suggests that the presumed endogenous GHRP-like ligand may participate in the orchestration of coordinated anterior pituitary hormone release.

scholarly journals Calpains mediate acute renal cell death: role of autolysis and translocation

2001 ◽  
Vol 281 (4) ◽  
pp. F728-F738 ◽  
Author(s):  
Xiuli Liu ◽  
Juanita J. Rainey ◽  
Jay F. Harriman ◽  
Rick G. Schnellmann
Keyword(s):  
Cell Death ◽  
Mitochondrial Function ◽  
Immunoblot Analysis ◽  
Calpain Inhibitor ◽  
Antimycin A ◽  
Rt Pcr ◽  
Plasma Membrane Permeability ◽  
Injury Death ◽  
Casein Zymography

The goals of this study were to determine 1) the expression of calpain isoforms in rabbit renal proximal tubules (RPT); 2) calpain autolysis and translocation, and calpastatin levels during RPT injury; and 3) the effect of a calpain inhibitor (PD-150606) on calpain levels, mitochondrial function, and ion transport during RPT injury. RT-PCR, immunoblot analysis, and FITC-casein zymography demonstrated the presence of only μ- and m-calpains in rabbit RPT. The mitochondrial inhibitor antimycin A decreased RPT μ- and m-calpain and calpastatin levels in conjunction with cell death and increased plasma membrane permeability. No increases in either μ- or m-calpain were observed in the membrane nor were increases observed in autolytic forms of either μ- or m-calpain in antimycin A-exposed RPT. PD-150606 blocked antimycin A-induced cell death, preserved calpain levels in antimycin A-exposed RPT, and promoted the recovery of mitochondrial function and active Na+ transport in RPT after hypoxia and reoxygenation. The present study suggests that calpains mediate RPT injury without undergoing autolysis or translocation, and ultimately they leak from cells subsequent to RPT injury/death. Furthermore, PD-150606 allows functional recovery after injury.

Body temperature elevation, exercise and serum prolactin concentrations

1985 ◽  
Vol 109 (4) ◽  
pp. 458-462 ◽  
Author(s):  
Stig Engkjær Christensen ◽  
Otto Jørgensen ◽  
Jan Møller ◽  
Niels Møller ◽  
Hans Ørskov
Keyword(s):  
Body Temperature ◽  
Normal Weight ◽  
Tympanic Temperature ◽  
Serum Prolactin ◽  
Pituitary Hormone ◽  
Relative Role ◽  
Hormone Release ◽  
Temperature Elevation ◽  
Body Temperature Increase

Abstract. Ten young healthy normal-weight males were studied in four test situations designed to elucidate the relative role of body temperature increase vs that of exercise per se for pituitary hormone release. Tympanic temperature was recorded continuously during the tests. Elevation of body temperature at rest induced by external heating resulted in parallel changes in serum prolactin (Prl), also found when temperature spontaneously returned towards normal. In contrast, temperature elevation of the same magnitude through exercise (450 kpm/min for 40 min) induced no change in Prl secretion. It is concluded that increase in core temperature is a stimulus of Prl secretion and suggested that exercise apparently inhibits the stimulatory effect.

scholarly journals Effect of steroids and nitric oxide on pituitary hormone release in ovariectomized, peripubertal rats

Reproduction ◽  
2005 ◽  
Vol 129 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Jill M Russell ◽  
E Murphree ◽  
J Janik ◽  
P Callahan
Keyword(s):  
Nitric Oxide ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Sprague Dawley ◽  
Lh Surge ◽  
Sprague Dawley Rats ◽  
17Β Estradiol

The purpose of this study was to determine the effects of the duration of steroid depletion on the steroid-induced luteinizing hormone and prolactin surges in ovariectomized, peripubertal female rats. Additionally, the role of nitric oxide (NO) in mediating the surge responses was determined. Peripubertal, 6-week-old, female Sprague-Dawley rats were ovariectomized. One or three weeks later, animals were injected with 17β-estradiol (50 μg, sc) followed 48 h later by progesterone (2.5 mg, sc). Effects of NO were examined by administeringl-arginine (300 mg/kg, ip). The response of ovariectomized, adult females to steroid treatment was also determined.One and three weeks after ovariectomy, steroid replacement produced an LH and prolactin surge in peripubertal animals. However, both the magnitude and duration of the LH surge was greater 3 weeks after ovariectomy. Whilel-arginine significantly enhanced the magnitude of the LH surge 1 week after ovariectomy, by 3 weeksl-arginine caused a decrease in the duration, but not the magnitude of the surge. In contrast,l-arginine did not affect either the magnitude or duration of the prolactin surge one week after ovariectomy, but diminished the magnitude after 3 weeks of steroid depletion. In adults, steroids induced significant increases in both LH and prolactin. These results demonstrate that sensitivity to NO stimulation of LH, but not prolactin secretion, is modulated by the duration of gonadal steroid hormone depletion. The differences in the responsiveness of LH and prolactin to steroid-induced stimulation in peripubertal animals demonstrate that these hormones are regulated by NO through different mechanisms.

An investigation of the effects of interleukin-1β on plasma arginine vasopressin in the rat: role of adrenal steroids

1994 ◽  
Vol 142 (2) ◽  
pp. 361-366 ◽  
Author(s):  
A J Chover-Gonzalez ◽  
S L Lightman ◽  
M S Harbuz
Keyword(s):  
Low Dose ◽  
High Dose ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Posterior Pituitary ◽  
Plasma Arginine ◽  
Posterior Pituitary Hormone ◽  
Circulating Levels ◽  
Pituitary Adrenal Axis

Abstract While the effects of cytokines on the hypothalamo-pituitary-adrenal axis have received a great deal of attention in recent years the effects of cytokines on posterior pituitary hormone release has been less well characterized. In the present study we have investigated the effects of a single i.p. injection of interleukin (IL)-1β on circulating levels of vasopressin (AVP) in the rat. We have found that the ability of IL-1β to increase plasma AVP is strongly influenced by circulating levels of glucocorticoid steroids. IL-1β did not affect plasma AVP in sham-operated control animals over the 4 h period of study. In contrast, following adrenalectomy we were able to stimulate AVP substantially with increases over the 4 h period. This effect was reduced by treatment of adrenalectomized rats with a low dose of dexamethasone and abolished with a high dose. These data suggest an inverse relationship between circulating levels of glucocorticoids and the ability of IL-1β to stimulate plasma AVP. Journal of Endocrinology (1994) 142, 361–366

scholarly journals Hypotonicity and peptide discharge from a single vesicle

2008 ◽  
Vol 295 (3) ◽  
pp. C624-C631 ◽  
Author(s):  
Jernej Jorgačevski ◽  
Matjaž Stenovec ◽  
Marko Kreft ◽  
Aleksandar Bajić ◽  
Boštjan Rituper ◽  
...  
Keyword(s):  
Time Course ◽  
Single Cells ◽  
Vesicle Fusion ◽  
Fusion Pore ◽  
Pituitary Hormone ◽  
Secretory Vesicles ◽  
Hormone Release ◽  
Prolactin Release ◽  
Average Pore ◽  
Single Vesicle

Neuroendocrine secretory vesicles discharge their cargo in response to a stimulus, but the nature of this event is poorly understood. We studied the release of the pituitary hormone prolactin by hypotonicity, because this hormone also contributes to osmoregulation. In perfused rat lactotrophs, hypotonicity resulted in a transient increase followed by a sustained depression of prolactin release, as monitored by radioimmunoassay. In single cells imaged by confocal microscopy, hypotonicity elicited discharge of the fluorescently labeled atrial natriuretic peptide cargo from ∼2% of vesicles/cell. In contrast, KCl-induced depolarization resulted in a response of ∼10% of vesicles/cell, with different unloading/loading time course of the two fluorescent probes. In cell-attached studies, discrete changes in membrane capacitance were recorded in both unstimulated and stimulated conditions, reflecting single vesicle fusion/fissions with the plasma membrane. In stimulated cells, the probability of occurrence of full fusion events was low and unchanged, whereas over 95% of fusion events were transient, with the open fusion pore probability, the average pore dwell-time, the frequency of occurrence, and the fusion pore conductance increased. Hypotonicity only rarely elicited new fusion events in silent membrane patches. The results indicate that, in hypotonicity-stimulated lactotrophs, transient vesicle fusion mediates hormone release.

Expression and localization of the multidrug resistance-associated protein 3 in rat small and large intestine

2002 ◽  
Vol 282 (4) ◽  
pp. G720-G726 ◽  
Author(s):  
Daniel Rost ◽  
Sven Mahner ◽  
Yuichi Sugiyama ◽  
Wolfgang Stremmel
Keyword(s):  
Multidrug Resistance ◽  
Large Intestine ◽  
Bile Salts ◽  
Intestinal Transport ◽  
Immunoblot Analysis ◽  
Organic Anions ◽  
Rt Pcr ◽  
Dependent Transport ◽  
Small And Large Intestine

Multidrug resistance-associated protein 3 (MRP3; symbol ABCC3), has been shown to mediate ATP-dependent transport of organic anions including 17β-glucuronosyl estradiol, glucuronosyl bilirubin, monovalent, and sulfated bile salts. MRP3 mRNA expression was reported in rat intestine suggesting a role of MRP3 in the intestinal transport. We examined the expression and localization of MRP3 in rat small and large intestine by RT-PCR, immunofluorescence, and immunoblot analysis. MRP3 was identified in all intestinal segments by RT-PCR. MRP3 expression was low in duodenum and jejunum but markedly increased in ileum and colon. With the use of a rat MRP3 specific antibody, MRP3 was localized to the basolateral domains of enterocytes. Immunofluorescence analysis and immunoblot analysis confirmed a strong expression of rat MRP3 in ileum and colon. In contrast, MRP2 was predominantly expressed in the proximal segments of rat small intestine. Our findings demonstrate a high expression of rat MRP3 in ileum and colon and provide evidence for an involvement of MRP3 in the ATP-dependent transport of organic anions, including bile salts from the enterocyte into blood.

Sign in / Sign up

Export Citation Format

Share Document