scholarly journals Hindbrain Administration of Estradiol Inhibits Feeding and Activates Estrogen Receptor-α-Expressing Cells in the Nucleus Tractus Solitarius of Ovariectomized Rats

Endocrinology ◽  
2007 ◽  
Vol 149 (4) ◽  
pp. 1609-1617 ◽  
Author(s):  
Sumpun Thammacharoen ◽  
Thomas A. Lutz ◽  
Nori Geary ◽  
Lori Asarian

17β-Estradiol (E2), acting via estrogen receptor (ER)-α, inhibits feeding in animals. One mechanism apparently involves an increase in the satiating potency of cholecystokinin (CCK) released from the small intestine by ingested food. For example, the satiating potency of intraduodenal lipid infusions is increased by E2 in ovariectomized rats; this increased satiation is dependent on CCK, and it is accompanied by increases in the numbers of ERα-positive cells that express c-Fos in a subregion of the caudal nucleus tractus solitarius (cNTS) that receives abdominal vagal afferent projections. To test whether direct administration of E2 to this area of the hindbrain is sufficient to inhibit food intake, we first implanted 0.2 μg estradiol benzoate (EB) in cholesterol or cholesterol alone either sc or onto the surface of the hindbrain over the cNTS. Food intake was significantly reduced after hindbrain EB implants but not after sc EB implants. Next we verified that equimolar hindbrain implants of E2 and EB had similar feeding-inhibitory effects and determined that only small amounts of E2 reached brain areas outside the dorsal caudal hindbrain after hindbrain implants of 3H-labeled E2. Neither plasma estradiol concentration nor plasma inflammatory cytokine concentration was increased by either hindbrain or sc EB implants. Finally, hindbrain EB implants, but not sc implants, increased c-Fos in ERα-positive cells in the cNTS after ip injection of 4 μg/kg CCK-8. We conclude that E2, acting via ERα in cNTS neurons, including neurons stimulated by ip CCK, is sufficient to inhibit feeding.

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5656-5666 ◽  
Author(s):  
Lori Asarian ◽  
Nori Geary

Part of the mechanism through which estradiol, acting via estrogen receptor (ERα) signaling, inhibits feeding in rats and mice is increasing the satiating potency of cholecystokinin (CCK) acting on peripheral CCK-1 receptors. Ingested lipid is a principal secretagogue of intestinal CCK, and intraduodenal lipid infusions elicit CCK-mediated satiation in animals and humans. Here we tested whether estradiol affects the satiating potency of intraduodenal lipid infusions in ovariectomized rats and, using c-Fos immunocytochemistry, searched for potential brain sites of ERα involved. Food-deprived ovariectomized rats with open gastric cannulas sham fed 0.8 m sucrose 2 d after estradiol (estradiol benzoate, 10 μg, sc) or vehicle injection. Estradiol markedly increased the satiating potency of intraduodenal infusions of Intralipid but not the satiating potency of L-phenylalanine (10 min infusions, 0.44 ml/min, 0.13 kcal/ml), which in male rats satiates via a CCK-independent mechanism. Estradiol had no significant effect in rats pretreated with the CCK-1 receptor antagonist Devazepide (1 mg/kg, ip). The effect of estradiol on intraduodenal Intralipid-induced satiation was mirrored by selective increases in the number of cells expressing c-Fos immunoreactivity in a circumscribed region of the nucleus tractus solitarius (NTS), just caudal to the area postrema (cNTS) but not elsewhere in the NTS or the hypothalamic paraventricular or arcuate nuclei. In addition, a significant proportion of cNTS c-Fos-positive cells also expressed ERα. These data provide behavioral and cellular evidence that estradiol-ERα signaling in cNTS neurons increases the satiating potency of endogenous CCK released in response to ingested lipid.


Appetite ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 334
Author(s):  
S. Thammacharoen ◽  
T.A. Lutz ◽  
N. Geary ◽  
L. Asarian

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 623
Author(s):  
Marit Rasmussen ◽  
Susanna Tan ◽  
Venkata S. Somisetty ◽  
David Hutin ◽  
Ninni Elise Olafsen ◽  
...  

ADP-ribosylation is a post-translational protein modification catalyzed by a family of proteins known as poly-ADP-ribose polymerases. PARP7 (TIPARP; ARTD14) is a mono-ADP-ribosyltransferase involved in several cellular processes, including responses to hypoxia, innate immunity and regulation of nuclear receptors. Since previous studies suggested that PARP7 was regulated by 17β-estradiol, we investigated whether PARP7 regulates estrogen receptor α signaling. We confirmed the 17β-estradiol-dependent increases of PARP7 mRNA and protein levels in MCF-7 cells, and observed recruitment of estrogen receptor α to the promoter of PARP7. Overexpression of PARP7 decreased ligand-dependent estrogen receptor α signaling, while treatment of PARP7 knockout MCF-7 cells with 17β-estradiol resulted in increased expression of and recruitment to estrogen receptor α target genes, in addition to increased proliferation. Co-immunoprecipitation assays revealed that PARP7 mono-ADP-ribosylated estrogen receptor α, and mass spectrometry mapped the modified peptides to the receptor’s ligand-independent transactivation domain. Co-immunoprecipitation with truncated estrogen receptor α variants identified that the hinge region of the receptor is required for PARP7-dependent mono-ADP-ribosylation. These results imply that PARP7-mediated mono-ADP-ribosylation may play an important role in estrogen receptor positive breast cancer.


Channels ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 516-527
Author(s):  
Meisheng Yu ◽  
Yuan Wei ◽  
Yanfang Zheng ◽  
Lili Yang ◽  
Long Meng ◽  
...  

2007 ◽  
Vol 292 (6) ◽  
pp. C2103-C2111 ◽  
Author(s):  
Takao Suzuki ◽  
Tomoharu Shimizu ◽  
Huang-Ping Yu ◽  
Ya-Ching Hsieh ◽  
Mashkoor A. Choudhry ◽  
...  

Although 17β-estradiol (E2) administration following trauma-hemorrhage prevents the suppression in splenocyte cytokine production, it remains unknown whether the salutary effects of 17β-estradiol are mediated via estrogen receptor (ER)-α or ER-β. Moreover, it is unknown which signaling pathways are involved in 17β-estradiol's salutary effects. Utilizing an ER-α- or ER-β-specific agonist, we examined the role of ER-α and ER-β in E2-mediated restoration of T-cell cytokine production following trauma-hemorrhage. Moreover, since MAPK, NF-κB, and activator protein (AP)-1 are known to regulate T-cell cytokine production, we also examined the activation of MAPK, NF-κB, and AP-1. Male rats underwent trauma-hemorrhage (mean arterial pressure 40 mmHg for 90 min) and fluid resuscitation. ER-α agonist propyl pyrazole triol (PPT; 5 μg/kg), ER-β agonist diarylpropionitrile (DPN; 5 μg/kg), 17β-estradiol (50 μg/kg), or vehicle (10% DMSO) was injected subcutaneously during resuscitation. Twenty-four hours thereafter, splenic T cells were isolated, and their IL-2 and IFN-γ production and MAPK, NF-κB, and AP-1 activation were measured. T-cell IL-2 and IFN-γ production was decreased following trauma-hemorrhage, and this was accompanied with a decrease in T-cell MAPK, NF-κB, and AP-1 activation. PPT or 17β-estradiol administration following trauma-hemorrhage normalized those parameters, while DPN administration had no effect. Since PPT, but not DPN, administration following trauma-hemorrhage was as effective as 17β-estradiol in preventing the T-cell suppression, it appears that ER-α plays a predominant role in mediating the salutary effects of 17β-estradiol on T cells following trauma-hemorrhage, and that such effects are likely mediated via normalization of MAPK, NF-κB, and AP-1 signaling pathways.


2001 ◽  
Vol 281 (3) ◽  
pp. R738-R746 ◽  
Author(s):  
Lisa A. Eckel ◽  
Nori Geary

The steroid hormone estradiol decreases meal size by increasing the potency of negative-feedback signals involved in meal termination. We used c-Fos immunohistochemistry, a marker of neuronal activation, to investigate the hypothesis that estradiol modulates the processing of feeding-induced negative-feedback signals within the nucleus of the solitary tract (NTS), the first central relay of the neuronal network controlling food intake, and within other brain regions related to the control of food intake. Chow-fed, ovariectomized rats were injected subcutaneously with 10 μg 17-β estradiol benzoate or sesame oil vehicle on 2 consecutive days. Forty-eight hours after the second injections, 0, 5, or 10 ml of a familiar sweet milk diet were presented for 20 min at dark onset. Rats were perfused 100 min later, and brain tissue was collected and processed for c-Fos-like immunoreactivity. Feeding increased the number of c-Fos-positive cells in the NTS, the paraventricular nucleus of the hypothalamus (PVN), and the central nucleus of the amygdala (CeA) in oil-treated rats. Estradiol treatment further increased this response in the caudal, subpostremal, and intermediate NTS, which process negative-feedback satiation signals, but not in the rostral NTS, which processes positive-feedback gustatory signals controlling meal size. Estradiol treatment also increased feeding-induced c-Fos in the PVN and CeA. These results indicate that modest amounts of food increase neuronal activity within brain regions implicated in the control of meal size in ovariectomized rats and that estradiol treatment selectively increases this activation. They also suggest that estradiol decreases meal size by increasing feeding-related neuronal activity in multiple regions of the distributed neural network controlling meal size.


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