Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 2557014

Adaptative decrease in expression of the mRNA for uncoupling protein and subunit II of cytochrome c oxidase in rat brown adipose tissue during pregnancy and lactation.

I Martin·M Giralt·O Viñas·R Iglesias·T Mampel·F Villarroya
View original source ↗Export metadata ↓

Abstract

Uncoupling-protein (UCP) mRNA expression is decreased to 15% of virgin control levels between days 10 and 15 of pregnancy, and remains at these low values during late pregnancy and lactation. Abrupt weaning of mid-lactating rats causes a slight but significant increase in UCP mRNA. Expression of mRNA for subunit II of cytochrome c oxidase (COII) decreased to half that of virgin control in late pregnancy and during lactation. Whereas COII mRNA expression is in step with the known modifications of brown-fat mitochondria content during the breeding cycle of the rat, UCP mRNA expression appears to be diminished much earlier than the mitochondrial proton-conductance-pathway activity. On the other hand, the reactivity of brown fat to increase expression of UCP and COII mRNAs in response to acute cold or noradrenaline treatment is not impaired during lactation.

Explore related subjects

Adipose Tissue, BrownAnimalsBlotting, NorthernCarrier ProteinsCold TemperatureElectron Transport Complex IVFemaleGene Expression Regulation, EnzymologicIon ChannelsLactationMembrane ProteinsMitochondrial ProteinsNorepinephrinePregnancyPregnancy, AnimalRNA, MessengerRatsRats, Inbred StrainsUncoupling Protein 1Journal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

I Martin, M Giralt, O Viñas, R Iglesias, T Mampel, F Villarroya. 1989-11-01. Adaptative decrease in expression of the mRNA for uncoupling protein and subunit II of cytochrome c oxidase in rat brown adipose tissue during pregnancy and lactation.. https://doi.org/10.1042/bj2630965

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Reduction of FDG uptake in brown adipose tissue in clinical patients by a single dose of propranolol.

PURPOSE: Uptake in brown adipose tissue (hibernating fat) is sometimes seen at FDG-PET examinations. Despite a characteristic appearance, this may hide clinically relevant uptake. Stimulation of the sympathetic nervous system increases glucose uptake of brown fat. We now re-examine patients with brown fat activity that could disguise tumour uptake after pre-treatment with propranolol (a non-selective beta-blocker) in order to reduce the uptake. Our first examinations of this kind are reported. METHODS: Eleven patients with strong brown fat uptake were studied. There was a mean of 5 days (range 2-8) between the examinations. At the second examination, 80 mg of propranolol was given orally 2 h before FDG administration. In addition to visual evaluation of the brown fat uptake, SUV assessments of the uptake in brown fat, lung, heart, liver, spleen and bone marrow were made. RESULTS: All patients showed complete or almost complete disappearance of the brown fat activity at the second examination (p < 0.001) both upon visual evaluation and when comparing SUVs. In seven patients there was also uptake in a known or strongly suspected malignancy, which remained unchanged between the examinations. Beyond an insignificant decrease in the myocardial uptake, there was no redistribution to the various examined organs at the second examination. CONCLUSION: Pre-treatment with a single dose of propranolol blocks the FDG uptake in brown adipose tissue, thereby increasing the specificity of the examination. The tumour uptake seems not to be impaired.

Adipose Tissue, Brown↗
PubMed2007

Elevated blood pressure in transgenic lipoatrophic mice and altered vascular function.

The role of perivascular fat in the control of vascular function was studied using lipoatrophic A-ZIP/F1 transgenic mice. Only a small amount of brown fat was found around the aorta but not around mesenteric arteries. Blood pressure of A-ZIP/F1 mice became higher than wild-type (WT) mice from 10 weeks of age. The presence of perivascular fat reduced the contraction of WT aorta to phenylephrine and serotonin, whereas this effect was either absent or less prominent in A-ZIP/F1 aorta. In WT mice, transfer of solution incubated with aorta with fat to aorta with fat removed caused a relaxation response, but not in A-ZIP/F1 mice, indicating the release of a relaxation factor from perivascular fat in WT aorta. This factor was acting through the activation of calcium-dependent potassium channels. Perfusion of phenylephrine to the isolated mesenteric bed caused a higher increase in perfusion pressure in A-ZIP/F1 than in WT mice. Contractile response of aorta to angiotensin II (Ang II) was mediated by Ang II type 1 receptors and was higher in A-ZIP/F1 than in WT mice. Expression of Ang II type 1 receptors but not Ang II type 2 receptors was higher in aorta of A-ZIP/F1 than WT mice. Treatment with an Ang II type 1 receptor antagonist (TCV 116, 10 mg/kg per day) for 2 weeks normalized the blood pressure of A-ZIP/F1 mice. These results suggest that the absence of perivascular fat tissue, which enhances the contractile response of the blood vessels to agonists, and an upregulation of vascular Ang II type 1 receptors in A-ZIP/F1 mice, are some of the mechanisms underlying the blood pressure elevation in these lipoatrophic mice.

Adipose Tissue, Brown↗
PubMed2007

Involvement of nitric oxide in noradrenaline-induced changes in the activity of antioxidant enzymes and lipid peroxidation in rat brown adipose tissue and heart.

The effect of exogenous noradrenaline (NA) (1.6 mg x kg(-1) i.p., 35 min prior sacrifice) on the activity of antioxidant enzymes (AOE) copper zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as lipid peroxides (LP) concentration were studied in the rat interscapular brown adipose tissue (IBAT) and heart of saline (controls) and N(omega)-nitro-L-arginine methyl ester (L-NAME) treated rats (10 mg x kg(-1), i.p., during 3 days and 20 min before NA). NA differently affects both AOE activities and LP production in the IBAT and heart. Thus, NA inhibited the activity of all IBAT AOE and LP production while in the heart it markedly increased CAT activity only, but had no effect on any of SODs activities and LP concentration. L-NAME, a nitric oxide synthase blocker, completely abolished the NA-induced inhibition of the IBAT AOE and LP production, whereas in the heart it was without effect. In conclusion, these results indicate that both NA and L-NAME effects on AOE activity and LP production are tissue specific and also suggest that nitric oxide mediates the NA-induced inhibition of AOE activity and LP production in the IBAT only.

Adipose Tissue, Brown↗