scholarly journals β-Adrenoceptors, but not α-adrenoceptors, stimulate AMP-activated protein kinase in brown adipocytes independently of uncoupling protein-1

Diabetologia ◽  
2005 ◽  
Vol 48 (11) ◽  
pp. 2386-2395 ◽  
Author(s):  
D. S. Hutchinson ◽  
E. Chernogubova ◽  
O. S. Dallner ◽  
B. Cannon ◽  
T. Bengtsson
2002 ◽  
Vol 282 (1) ◽  
pp. C105-C112 ◽  
Author(s):  
Bibian García ◽  
Maria-Jesús Obregón

To study the effect of the mitogens epidermal growth factor (EGF), acidic and basic fibroblast growth factors (aFGF and bFGF), and vasopressin on brown adipocyte differentiation, we analyzed the expression of uncoupling protein-1 (UCP-1) mRNA. Quiescent brown preadipocytes express high levels of UCP-1 mRNA in response to triiodothyronine (T3) and norepinephrine (NE). The addition of serum or the mitogenic condition aFGF + vasopressin + NE or EGF + vasopressin + NE decreases UCP-1 mRNA. A second addition of mitogens further decreases UCP-1 mRNA. Treatment with aFGF or bFGF alone increases UCP-1 mRNA, whereas the addition of EGF or vasopressin dramatically reduces UCP-1 mRNA levels. The continuous presence of T3 increases UCP-1 mRNA levels in cells treated with EGF, aFGF, or bFGF. The effect of T3 on the stimulation of DNA synthesis also was tested. T3 inhibits the mitogenic activity of aFGF and bFGF. In conclusion, mitogens like aFGF or bFGF allow brown adipocyte differentiation, whereas EGF and vasopressin inhibit the differentiation process. T3 behaves as an important hormone that regulates both brown adipocyte proliferation and differentiation.


2006 ◽  
Vol 60 (5) ◽  
pp. 569-575 ◽  
Author(s):  
Petr Brauner ◽  
Pavel Kopecky ◽  
Pavel Flachs ◽  
Ondrej Kuda ◽  
Jaroslav Vorlicek ◽  
...  

2004 ◽  
Vol 18 (9) ◽  
pp. 2302-2311 ◽  
Author(s):  
Michael A. Nolan ◽  
Maria A. Sikorski ◽  
G. Stanley McKnight

Abstract Mice lacking the RIIβ regulatory subunit of protein kinase A exhibit a 50% reduction in white adipose tissue stores compared with wild-type littermates and are resistant to diet-induced obesity. RIIβ−/− mice also have an increase in resting oxygen consumption along with a 4-fold increase in the brown adipose-specific mitochondrial uncoupling protein 1 (UCP1). In this study, we examined the basis for UCP1 induction and tested the hypothesis that the induced levels of UCP1 in RIIβ null mice are essential for the lean phenotype. The induction of UCP1 occurred at the protein but not the mRNA level and correlated with an increase in mitochondria in brown adipose tissue. Mice lacking both RIIβ and UCP1 (RIIβ−/−/Ucp1−/−) were created, and the key parameters of metabolism and body composition were studied. We discovered that RIIβ−/− mice exhibit nocturnal hyperactivity in addition to the increased oxygen consumption at rest. Disruption of UCP1 in RIIβ−/− mice reduced basal oxygen consumption but did not prevent the nocturnal hyperactivity. The double knockout animals also retained the lean phenotype of the RIIβ null mice, demonstrating that induction of UCP1 and increased resting oxygen consumption is not the cause of leanness in the RIIβ mutant mice.


Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Scott D. Clarke ◽  
Iain J. Clarke ◽  
Alexandra Rao ◽  
Michael A. Cowley ◽  
Belinda A. Henry

Adiposity is regulated in a sexually divergent manner. This is partly due to sex steroids, but the differential effects of androgens in males and females are unclear. We investigated effects of testosterone on energy balance in castrated male (n = 6) and female sheep (n = 4), which received 3 × 200 mg testosterone implants for 2 wk or blank implants (controls). Temperature probes were implanted into retroperitoneal fat and skeletal muscle. Blood samples were taken to measure metabolites and insulin. In males, muscle and fat biopsies were collected to measure uncoupling protein (UCP) mRNA and phosphorylation of AMP-activated protein kinase and Akt. Testosterone did not change food intake in either sex. Temperature in muscle was higher in males than females, and testosterone reduced heat production in males only. In fat, however, temperature was higher in the castrate males compared with females, and there was no effect of testosterone treatment in either sex. Preprandial glucose levels were lower, but nonesterified fatty acids were higher in females compared with males, irrespective of testosterone. In males, the onset of feeding increased UCP1 and UCP3 mRNA levels in skeletal muscle, without an effect of testosterone. During feeding, testosterone reduced glucose levels in males only but did not alter the phosphorylation of AMP-activated protein kinase or Akt in muscle. Thus, testosterone maintains lower muscle and fat temperatures in males but not females. The mechanism underlying this sex-specific effect of testosterone is unknown but may be due to sexual differentiation of the brain centers controlling energy expenditure.


2021 ◽  
Vol 10 (2) ◽  
pp. 396-401
Author(s):  
Natalia Danayati

Pendahuluan: Irisin merupakan miokin baru yang menghubungkan aktivitas fisik yang berhubungan dengan peningkatan kinerja metabolisme dan berkaitanan dengan pencoklatan jaringan adiposa putih menjadi coklat. Tujuan: Mengetahui pengaruh irisin pada pencoklatan lemak putih. Metode: Menggunakan studi literatur dari sumber ilmiah dengan meringkas dari publikasi dan membandingkan hasil yang disajikan. Hasil: Irisin yang disekresikan dari otot, akan menstimulasi ekspresi dari uncoupling protein 1 (UCP1) dalam adiposit yang menyebabkan pencoklatan jaringan adiposa putih melalui p38 mitogen-activated protein kinase (MAPK) dan melalui extracellular-signal regulated kinase (ERK). Kesimpulan: Irisin yang disekresikan otot rangka akan mengekspresikan UPC-1 di jaringan adiposa yang menyebabkan jaringan adiposa putih menjadi coklat dan peningkatan aktivitas thermogenesis.


2021 ◽  
Vol 22 (16) ◽  
pp. 8640
Author(s):  
Minh-Hanh Thi Nguyen ◽  
Dat Da Ly ◽  
Nhung Thi Nguyen ◽  
Xu-Feng Qi ◽  
Hyon-Seung Yi ◽  
...  

Thyroid hormones, including 3,5,3′-triiodothyronine (T3), cause a wide spectrum of genomic effects on cellular metabolism and bioenergetic regulation in various tissues. The non-genomic actions of T3 have been reported but are not yet completely understood. Acute T3 treatment significantly enhanced basal, maximal, ATP-linked, and proton-leak oxygen consumption rates (OCRs) of primary differentiated mouse brown adipocytes accompanied with increased protein abundances of uncoupling protein 1 (UCP1) and mitochondrial Ca2+ uniporter (MCU). T3 treatment depolarized the resting mitochondrial membrane potential (Ψm) but augmented oligomycin-induced hyperpolarization in brown adipocytes. Protein kinase B (AKT) and mammalian target of rapamycin (mTOR) were activated by T3, leading to the inhibition of autophagic degradation. Rapamycin, as an mTOR inhibitor, blocked T3-induced autophagic suppression and UCP1 upregulation. T3 increases intracellular Ca2+ concentration ([Ca2+]i) in brown adipocytes. Most of the T3 effects, including mTOR activation, UCP1 upregulation, and OCR increase, were abrogated by intracellular Ca2+ chelation with BAPTA-AM. Calmodulin inhibition with W7 or knockdown of MCU dampened T3-induced mitochondrial activation. Furthermore, edelfosine, a phospholipase C (PLC) inhibitor, prevented T3 from acting on [Ca2+]i, UCP1 abundance, Ψm, and OCR. We suggest that short-term exposure of T3 induces UCP1 upregulation and mitochondrial activation due to PLC-mediated [Ca2+]i elevation in brown adipocytes.


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