scholarly journals Regulation of GH secretagogue receptor gene expression in the rat nodose ganglion

2007 ◽  
Vol 194 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Miho Sato ◽  
Keiko Nakahara ◽  
Mikiya Miyazato ◽  
Kenji Kangawa ◽  
Noboru Murakami
Keyword(s):  
Mrna Expression ◽  
Receptor Gene ◽  
Nodose Ganglion ◽  
Mrna Levels ◽  
Dynamic Changes ◽  
Ghrelin Receptor ◽  
Axon Terminals ◽  
Gastrointestinal Peptides ◽  
The Brain ◽  
Receptor Gene Expression

It has been shown that the ghrelin receptor, GH secretagogue receptor (GHS-R), is synthesized in neurons of the nodose ganglion and then transmitted to axon terminals, where it binds to ghrelin. The orexigenic signal of ghrelin secreted from the stomach is transmitted to the brain via the vagal afferent nerve. To explore the regulation of GHS-R synthesis in the nodose ganglion, we examined whether or not GHS-R type a mRNA expression shows circadian rhythm, and is affected by starvation, vagotomy, or i.v. administration of gastrointestinal peptides. Nodose ganglion GHS-R mRNA levels showed a diurnal rhythm, being high during periods of light and low during darkness. Although starvation tended to increase the level of GHS-R mRNA, a more significant increase was observed upon re-feeding. Vagotomy decreased the level of GHS-R mRNA significantly in comparison with animals that underwent a sham procedure. Cholecystokinin and gastrin increased the level of GHS-R mRNA after 2 h, but after 4 h, the level decreased. These results suggest that GHS-R synthesis in the nodose ganglion is regulated centrally and peripherally by neuronal and humoral information, and that these dynamic changes of GHS-R mRNA expression may be involved in the regulation of feeding by ghrelin.

Developmental changes in endothelin expression and activity in the ovine fetal lung

2000 ◽  
Vol 278 (4) ◽  
pp. L785-L793 ◽  
Author(s):  
D. Dunbar Ivy ◽  
Timothy D. le Cras ◽  
Thomas A. Parker ◽  
Jeanne P. Zenge ◽  
Malathi Jakkula ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Vascular Tone ◽  
Receptor Gene ◽  
Receptor Activity ◽  
Mrna Levels ◽  
Developmentally Regulated ◽  
Receptor Mrna ◽  
Fetal Lamb ◽  
Receptor Gene Expression

Mechanisms that regulate endothelin (ET) in the perinatal lung are complex and poorly understood, especially with regard to the role of ET before and after birth. We hypothesized that the ET system is developmentally regulated and that the balance of ETAand ETB receptor activity favors vasoconstriction. To test this hypothesis, we performed a series of molecular and physiological studies in the fetal lamb, newborn lamb, and adult sheep. Lung preproET-1 mRNA levels, tissue ET peptide levels, and cellular localization of ET-1 expression were determined by Northern blot analysis, peptide assay, and immunohistochemistry in distal lung tissue from fetal lambs between 70 and 140 days (term = 145 days), newborn lambs, and ewes. Lung mRNA expression for the ETA and ETB receptors was also measured at these ages. We found that preproET-1 mRNA expression increased from 113 to 130 days gestation. Whole lung ET protein content was highest at 130 days gestation but decreased before birth in the fetal lamb lung. Immunolocalization of ET-1 protein showed expression of ET-1 in the vasculature and bronchial epithelium at all gestational ages. ETA receptor mRNA expression and ETB receptor mRNA increased from 90 to 125 and 135 days gestation. To determine changes in activity of the ETA and ETBreceptors, we studied the effect of selective antagonists to the ETA or ETB receptors at 120, 130, and 140 days of fetal gestation. ETA receptor-mediated vasoconstriction increased from 120 to 140 days, whereas blockade of the ETBreceptor did not change basal fetal pulmonary vascular tone at any age examined. We conclude that the ET system is developmentally regulated and that the increase in ETA receptor gene expression correlates with the onset of the vasodilator response to ETA receptor blockade. Although ETB receptor gene expression increases during late gestation, the balance of ET receptor activity favors vasoconstriction under basal conditions. We speculate that changes in ET receptor activity play important roles in regulation of pulmonary vascular tone in the ovine fetus.

scholarly journals Characterization and Regulation of Type A Endothelin Receptor Gene Expression in Bovine Luteal Cell Types

Endocrinology ◽  
1999 ◽  
Vol 140 (5) ◽  
pp. 2110-2116 ◽  
Author(s):  
Roni Mamluk ◽  
Nitzan Levy ◽  
Bo Rueda ◽  
John S. Davis ◽  
Rina Meidan
Keyword(s):  
Gene Expression ◽  
Receptor Gene ◽  
Cell Types ◽  
Cell Populations ◽  
Mrna Levels ◽  
Factor I ◽  
Receptor Mrna ◽  
Progesterone Production ◽  
Eta Receptor ◽  
Receptor Gene Expression

Abstract Our previous studies demonstrated that endothelin-1 (ET-1), a 21-amino acid vasoconstrictor peptide, has a paracrine regulatory role in bovine corpus luteum (CL). The peptide is produced within the gland where it inhibits progesterone production by acting via the selective type A endothelin (ETA) receptors. The present study was designed to characterize ETA receptor gene expression in different ovarian cell types and its hormonal regulation. ETA receptor messenger RNA (mRNA) levels were high in follicular cells as well as in CL during luteal regression. At this latter stage, high ETA receptor expression concurred with low prostaglandin F2α receptor mRNA. The ETA receptor gene was expressed by all three major cell populations of the bovine CL; i.e. small and large luteal cells, as well as in luteal endothelial cells. Among these various cell populations, the highest ETA receptor mRNA levels were found in endothelial cells. cAMP elevating agents, forskolin and LH, suppressed ETA receptor mRNA expression in luteinized theca cells (LTC). This inhibition was dose dependent and was evident already after 24 h of incubation. In luteinized granulosa cells (LGC), 10 and 100 ng/ml of insulin-like growth factor I and insulin (only at a concentration of 2000 ng/ml) markedly decreased ETA receptor mRNA levels. In both LGC and LTC there was an inverse relationship between ETA receptor gene expression and progesterone production; insulin (in LGC) and forskolin (in LTC) enhanced progesterone production while inhibiting ETA receptor mRNA levels. Our findings may therefore suggest that, during early stages of luteinization when peak levels of both LH and insulin-like growth factor I exist, the expression of ETA receptors in the gland are suppressed. This study demonstrates physiologically relevant regulatory mechanisms controlling ETA receptor gene expression and further supports the inhibitory role of ET-1 in CL function.

scholarly journals Circulating leptin during ovine pregnancy in relation to maternal nutrition, body composition and pregnancy outcome

2001 ◽  
Vol 169 (3) ◽  
pp. 465-476 ◽  
Author(s):  
L Thomas ◽  
JM Wallace ◽  
RP Aitken ◽  
JG Mercer ◽  
P Trayhurn ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Composition ◽  
Adipose Tissue ◽  
Dietary Intake ◽  
Leptin Receptor ◽  
Maternal Nutrition ◽  
Receptor Gene ◽  
Mrna Levels ◽  
Tissue Samples ◽  
Receptor Gene Expression

This study examined the pattern of circulating leptin in age-matched sheep during adolescent pregnancy, and its relationship with maternal dietary intake, body composition and tissue expression of the leptin gene. Overfeeding the adolescent pregnant ewe results in rapid maternal growth at the expense of the placenta, leading to growth restriction in the fetus, compared with normal fed controls. Our results demonstrate that, in the adolescent ewe, overfeeding throughout pregnancy was associated with higher maternal leptin concentrations, when compared with moderately fed controls (P<0.05), with no peak in circulating leptin towards the end of pregnancy. There was a close correlation between indices of body composition and circulating leptin levels at day 104 of gestation and at term (P<0.03). Further, when the dietary intake was switched from moderate to high, or high to moderate, at day 50 of gestation, circulating leptin levels changed rapidly, in parallel with the changes in dietary intake. Leptin mRNA levels and leptin protein in perirenal adipose tissue samples, taken at day 128 of gestation, were higher in overfed dams (P<0.04), suggesting that adipose tissue was the source of the increase in circulating leptin in the overnourished ewes. Leptin protein was also detected in placenta but leptin gene expression was negligible. However, leptin receptor gene expression was detected in the ovine placenta, suggesting that the placenta is a target organ for leptin. A negative association existed between maternal circulating leptin and fetal birth weight, placental/cotyledon weight and cotyledon number. In conclusion, in this particular ovine model, hyperleptinaemia was not observed during late pregnancy. Instead, circulating leptin concentrations reflected increased levels of leptin secretion by adipose tissue primarily as a result of the increase in body fat deposition, due to overfeeding. However, there appears to be a direct effect of overfeeding, particularly in the short term. In the nutritional switch-over study, circulating leptin concentrations changed within 48 h of the change in dietary intake. The presence of leptin protein and leptin receptor gene expression in the placenta suggests that leptin could be involved in nutrient partitioning during placental and/or fetal development.

scholarly journals Effect of mother alcoholization on the activity of ghrelin system in prenatal and early postnatal periods of rat offspring

2015 ◽  
Vol 13 (2) ◽  
pp. 10-13 ◽  
Author(s):  
Marat Igorevich Airapetov ◽  
Platon Platonovich Khokhlov ◽  
Eugeny Rudolfovich Bychkov ◽  
Edgar Arturovich Sekste ◽  
Natalia Dmitrievna Yakushina ◽  
...  
Keyword(s):  
Blood Serum ◽  
Mrna Expression ◽  
Brain Structures ◽  
Postnatal Period ◽  
Receptor Expression ◽  
Dopaminergic Receptors ◽  
Adult Rats ◽  
Ghrelin Receptor ◽  
Chronic Alcoholization ◽  
The Brain

The purpose of the paper was to study both the desacylghrelin (unacylated ghrelin) level in the blood serum and expression of mRNA ghrelin receptor in the brain structures in ontogeny after chronic alcoholization in rats. The results proved that the prenatal effect of ethanol negatively affected the maturation of dopaminergic and ghrelin systems of the brain as well as involvement of ghrelin system in mechanisms of alcohol dependence formation. The decrease of COMT mRNA expression simultaneoully with the increase of expression of D2 long and short isoforms of dopaminergic receptors and misbalance of ghrelin system were observed. Alcoholization of mothers reduced desacylghrelin level in the blood serum in early postnatal period in offsprings although mRNA expression of ghrelin receptor in the brain was elevated. Chronic alcoholization of adult rats also affected the ghrelin system. In the alcoholiztion process, the reduced contents of desacylghrelin in the blood serum with compensatory increase of ghrelin receptor expression in the brain were registered. After withdrawal of ethanol, the recovery of desacylghrelin level (tendency to normalization) was observed.

scholarly journals Modulation of glomerular endothelin and endothelin receptor gene expression in aminonucleoside-induced nephrosis.

1995 ◽  
Vol 5 (8) ◽  
pp. 1585-1590
Author(s):  
T Nakamura ◽  
I Ebihara ◽  
M Fukui ◽  
S Osada ◽  
Y Tomino ◽  
...  
Keyword(s):  
Gene Expression ◽  
Receptor Gene ◽  
Mrna Level ◽  
Experimental Period ◽  
Receptor Expression ◽  
Mrna Levels ◽  
Puromycin Aminonucleoside ◽  
Receptor Mrna ◽  
Etb Receptor ◽  
Receptor Gene Expression

This study assessed glomerular endothelin (ET)-1, ET-3, and ET-receptor A and B mRNA levels in puromycin aminonucleoside (PAN)-induced nephrosis. During the nephrotic stage, 8 days after PAN injection, ET-1 and ETB receptor mRNA were elevated by 2.8 +/- 0.8-fold (P < 0.01) and 2.4 +/- 0.9-fold (P < 0.01), respectively, as compared with controls. These mRNA levels decreased to control levels by Day 20, when the nephrosis was in remission. In contrast, glomerular ETA receptor mRNA levels did not change in PAN nephrosis or control rats during the experimental period. ET-3 mRNA was not detected in the glomeruli of PAN nephrosis or control rats. Additionally, plasma ET concentration and glomerular ET production were measured in PAN nephrosis and control rats by radio-immunoassay. Eight days after PAN injection, ET-1 levels in plasma and glomeruli were not significantly altered in rats with PAN-induced nephrosis (glomeruli, 104.68 +/- 16.46 pg/mg of protein versus 98.24 +/- 13.68 pg/mg of protein; plasma, 2.68 +/- 1.10 versus 2.52 +/- 0.98 pg/mL). The administration of methylprednisolone to PAN rats resulted in the rapid disappearance of proteinuria and partially attenuated the increased ET-1 and ETB receptor gene expression in the glomeruli. These data indicate that glomerular ET-1 and ETB receptor expression in PAN nephrosis in increased at the mRNA level and that methylprednisolone treatment results in an attenuated increase.

Sign in / Sign up

Export Citation Format

Share Document