Postnatal development of uncoupling protein, uncoupling protein mRNA, and GLUT4 in adipose tissues of goats

1993 ◽  
Vol 265 (3) ◽  
pp. R676-R682 ◽  
Author(s):  
P. Trayhurn ◽  
M. E. Thomas ◽  
J. S. Keith

Adipose tissues have been characterized in newborn goats on the basis of the presence of the 32,000-M(r) mitochondrial uncoupling protein (UCP) diagnostic of brown fat, and early postnatal developmental changes have been determined. Both internal (perirenal, pericardial, and omental) and subcutaneous (hindlimb and neck regions) adipose tissues in newborn goats contained UCP and are therefore brown fat. The insulin-sensitive glucose transporter, GLUT4, was also present in adipose tissues of newborn goats, implying a potential for insulin-stimulated glucose uptake at birth. UCP was still evident in the perirenal fat of goats at 3 wk of age, but the mitochondrial concentration was only 4%, and the amount per cell a mere 0.2%, of that in the newborn. UCP was not detectable, however, in either the omental or subcutaneous adipose tissue at 3 wk of age and had disappeared from the subcutaneous fat before 2 wk. In contrast to UCP, GLUT4 remained throughout the initial 3 wk of postnatal life. The mRNA for UCP was detected in perirenal adipose tissue of newborn goats, indicating that the gene coding for the protein is being expressed at around birth. UCP mRNA was not, however, detectable in the other fat depots; nor was it evident in the perirenal adipose tissue at > or = 2.5 days of age. It is concluded that the adipose tissues of newborn goats (both internal and subcutaneous) represent brown fat and that there is a rapid transition toward white fat over the first weeks of life. This transition occurs at different rates in different depots but is not markedly faster in goats than in other ruminants.(ABSTRACT TRUNCATED AT 250 WORDS)

1991 ◽  
Vol 260 (6) ◽  
pp. R1229-R1234 ◽  
Author(s):  
P. Soppela ◽  
M. Nieminen ◽  
S. Saarela ◽  
J. S. Keith ◽  
J. N. Morrison ◽  
...  

Reindeer inhabit a severe arctic or subarctic environment, with the young born in early spring under adverse weather conditions. The extreme northern climate imposes a major thermal challenge to the newborn, and in the present study we have examined fetal, neonatal, and young (from 2 wk before birth to 16 mo postpartum) semidomesticated reindeer from northern Finland for the presence of thermogenic brown adipose tissue. Adipose tissues were removed, mitochondria were prepared, and the proteins were separated by molecular weight and blotted onto nitrocellulose membranes. The membranes were then probed for the presence of the 32,000-relative molecular weight mitochondrial uncoupling protein (UCP) unique to brown fat by use of a rabbit anti-(ground squirrel UCP) serum. Immunoreactivity at the molecular weight characteristic of UCP was present in perirenal, abdominal, inter(pre)scapular, sternal, intralumbar, vertebral, tracheal, inguinal, and omental-mesenteral adipose tissues of newborn reindeer (0-2 days of age). No immunoreactivity was detected in coronary adipose tissue. UCP was found at high levels in interscapular and perirenal adipose tissues of fetal reindeer at 2 wk before birth. Although the protein was present during the first few days postpartum, little immunoreactivity was found at 1 mo of age, and none was evident by 2 mo. UCP and its mRNA were also apparent in perirenal adipose tissue of the newborn of another species of Cervidae, the red deer. It is concluded, on the basis of the immunologic identification of UCP, that most adipose tissues of newborn reindeer represent functional brown fat but that there is a subsequent conversion to white adipose tissue by the 2nd mo of life.(ABSTRACT TRUNCATED AT 250 WORDS)


1996 ◽  
Vol 270 (5) ◽  
pp. E768-E775 ◽  
Author(s):  
J. Kopecky ◽  
Z. Hodny ◽  
M. Rossmeisl ◽  
I. Syrovy ◽  
L. P. Kozak

We seek to determine whether increased energy dissipation in adipose tissue can prevent obesity. Transgenic mice with C57BL6/J background and the adipocyte lipid-binding protein (aP2) gene promoter directing expression of the mitochondrial uncoupling protein (UCP) gene in white and brown fat were used. Physiologically, UCP is essential for nonshivering thermogenesis in brown fat. Mice were assigned to a chow or a high-fat (HF) diet at 3 mo of age. Over the next 25 wk, gains of body weight were similar in corresponding subgroups (n = 6-8) of female and male mice: 4-5 g in chow nontransgenic and transgenic, 20 g in HF nontransgenic, and 9-11 g in HF transgenic mice. The lower body weight gain in the HF transgenic vs. nontransgenic mice corresponded to a twofold lower feed efficiency. Gonadal fat was enlarged, but subcutaneous white fat was decreased in the transgenic vs. nontransgenic mice in both dietary conditions. The results suggest that UCP synthesized from the aP2 gene promoter is capable of reducing dietary obesity.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marianne Bléher ◽  
Berbang Meshko ◽  
Isabelle Cacciapuoti ◽  
Rachel Gergondey ◽  
Yoann Kovacs ◽  
...  

Abstract In mice, exercise, cold exposure and fasting lead to the differentiation of inducible-brown adipocytes, called beige adipocytes, within white adipose tissue and have beneficial effects on fat burning and metabolism, through heat production. This browning process is associated with an increased expression of the key thermogenic mitochondrial uncoupling protein 1, Ucp1. Egr1 transcription factor has been described as a regulator of white and beige differentiation programs, and Egr1 depletion is associated with a spontaneous increase of subcutaneous white adipose tissue browning, in absence of external stimulation. Here, we demonstrate that Egr1 mutant mice exhibit a restrained Ucp1 expression specifically increased in subcutaneous fat, resulting in a metabolic shift to a more brown-like, oxidative metabolism, which was not observed in other fat depots. In addition, Egr1 is necessary and sufficient to promote white and alter beige adipocyte differentiation of mouse stem cells. These results suggest that modulation of Egr1 expression could represent a promising therapeutic strategy to increase energy expenditure and to restrain obesity-associated metabolic disorders.


2020 ◽  
Author(s):  
Marianne Bléher ◽  
Berbang Meshko ◽  
Rachel Gergondey ◽  
Yoann Kovacs ◽  
Delphine Duprez ◽  
...  

AbstractExercise, cold exposure and fasting lead to the differentiation of inducible-brown adipocytes, called beige adipocytes, within white adipose tissue and have beneficial effects on fat burning and metabolism, through heat production. This browning process is associated with an increased expression of the key thermogenic mitochondrial uncoupling protein 1, Ucp1. Egr1 transcription factor has been described as a regulator of white and beige differentiation programs, and Egr1 depletion is associated with a spontaneous increase of subcutaneous white adipose tissue browning, in absence of external stimulation. Here, we demonstrate that Egr1 mutant mice exhibit a restrained Ucp1 expression specifically increased in subcutaneous fat, resulting in a metabolic shift to a more brown-like, oxidative metabolism, which was not observed in other fat depots. In addition, Egr1 is necessary and sufficient to promote white and alter beige adipocyte differentiation of mouse stem cells. These results suggest that modulation of Egr1 expression could represent a promising therapeutic strategy to increase energy expenditure and to restrain obesity-associated metabolic disorders.


2021 ◽  
Vol 248 (1) ◽  
pp. R19-R28
Author(s):  
Michael E Symonds ◽  
Mark Pope ◽  
Ian Bloor ◽  
James Law ◽  
Reham Alagal ◽  
...  

Adipose tissue is usually laid down in small amounts in the foetus and is characterised as possessing small amounts of the brown adipose tissue-specific mitochondrial uncoupling protein (UCP)1. In adults, a primary factor determining the abundance and function of UCP1 is ambient temperature. Cold exposure causes activation and the rapid generation of heat through the free flow of protons across the mitochondria with no requirement to convert ADP to ATP. In rodents, housing at an ambient temperature below thermoneutrality promotes the appearance of beige like adipocytes. These arise as discrete regions of UCP1 containing cells in white fat depots. There is increasing evidence to show that to gain credible translational results on brown and beige fat function in rodent models that they should be housed at thermoneutrality. This not only reflects the type of environment in which humans spend a majority of their time, but is in accord with the rise of global temperature caused by industrialisation and the uncontrolled burning of fossil fuels. There is now good evidence in adult humans, that stimulating brown fat can improve glucose homeostasis which can be achieved either by nutritional or pharmacological interventions. The challenge, therefore, is to establish credible developmental models in animals maintained at thermoneutrality which will elucidate the true impact of nutrition. The primary focus should fall specifically on the components of breast milk and how these modulate long term effects on brown or beige fat development and function.


1989 ◽  
Vol 67 (12) ◽  
pp. 1480-1485 ◽  
Author(s):  
Paul Trayhurn ◽  
Norman J. Temple ◽  
Johny Van Aerde

Adipose tissues and other tissues of the pig have been examined for the presence of the mitochondrial "uncoupling protein," characteristic of brown adipose tissue, in order to assess whether brown fat is present in this species. Mitochondria were prepared from various tissues and the proteins separated on the basis of molecular weight by sodium dodecyl sulphate – polyacrylamide gel electrophoresis. Immunoblotting procedures were then used to probe for uncoupling protein, employing a rabbit anti-(rat uncoupling protein) serum. Pigs were examined at 4 days, 4 weeks, and 8 weeks of age. No evidence for the presence of uncoupling protein was found at any of these ages. The protein was, however, readily detected in brown adipose tissue from rats, mice, golden hamsters, guinea pigs, Richardson's ground squirrel, and lambs. An additional group of pigs was acclimated to the cold (10 °C) for a period of 10 days prior to the examination of tissues, but again uncoupling protein was not detected in any tissue. These results indicate that uncoupling protein is either absent from adipose tissues of the pig or is present at such a low concentration that it is unlikely to support thermogenesis. It is concluded that the pig does not contain adipose tissue that is functionally "brown;" adipose tissues in this species appear to be exclusively "white."Key words: brown adipose tissue, white adipose tissue, uncoupling protein, thermogenesis, immunoblotting.


1998 ◽  
Vol 274 (3) ◽  
pp. E527-E533 ◽  
Author(s):  
Bohumír Stefl ◽  
Alena Janovská ◽  
Zdenek Hodný ◽  
Martin Rossmeisl ◽  
Milada Horáková ◽  
...  

The role of brown adipose tissue in total energy balance and cold-induced thermogenesis was studied. Mice expressing mitochondrial uncoupling protein 1 (UCP-1) from the fat-specific aP2 gene promoter (heterozygous and homozygous aP2 -Ucp transgenic mice) and their nontransgenic C57BL6/J littermates were used. The transgenic animals are resistant to obesity induced by a high-fat diet, presumably due to ectopic synthesis of UCP-1 in white fat. These animals exhibited atrophy of brown adipose tissue, as indicated by smaller size of brown fat and reduction of its total UCP-1 and DNA contents. Norepinephrine-induced respiration (measured in pentobarbital sodium-anesthetized animals) was decreased proportionally to the dosage of the transgene, and the homozygous (but not heterozygous) transgenic mice exhibited a reduction in their capacity to maintain body temperature in the cold. Our results indicate that the role of brown fat in cold-induced thermogenesis cannot be substituted by increased energy expenditure in other tissues.


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