Reduction of dietary obesity in aP2-Ucp transgenic mice: mechanism and adipose tissue morphology

1996 ◽  
Vol 270 (5) ◽  
pp. E776-E786 ◽  
Author(s):  
J. Kopecky ◽  
M. Rossmeisl ◽  
Z. Hodny ◽  
I. Syrovy ◽  
M. Horakova ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Transgenic Mice ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Brown Fat ◽  
Small Cells ◽  
Cytochrome Oxidase Activity ◽  
Tissue Morphology ◽  
Brown Adipose ◽  
White Fat

C57BL6/J mice with the expression of the mitochondrial uncoupling protein (UCP) gene from the fat-specific aP2 gene promoter were used to study the mechanism by which the aP2-Ucp transgene affects adiposity and reduces high-fat diet induced obesity. In the transgenic mice, UCP synthesized in white fat was inserted into mitochondria, and oxygen uptake by epididymal fat fragments indicated UCP-induced thermogenesis. The respirometry data, UCP content, cytochrome oxidase activity, and tissue morphology suggested functional involution of brown fat. Despite 25- to 50-fold lower mitochondrial cytochrome oxidase activity in white than in brown fat cells, total oxidative capacity in white and brown adipose tissue is comparable. Appearance of novel small cells in the gonadal fat of the transgenic mice was associated with a higher DNA content than that of the nontransgenic mice. The results prove a potential of transgenically altered mitochondria in white fat to modulate adiposity and energy expenditure and suggest the existence of a yet unidentified site-specific link between energy metabolism in adipocytes and cellularity.

scholarly journals GDP binding to brown-adipose-tissue mitochondria of mice treated chronically with corticosterone

1983 ◽  
Vol 214 (1) ◽  
pp. 265-268 ◽  
Author(s):  
K S Galpin ◽  
R G Henderson ◽  
W P T James ◽  
P Trayhurn
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Cytochrome Oxidase Activity ◽  
Acute Response ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis ◽  
Ad Libitum ◽  
Stimulation Of

Cytochrome oxidase activity and mitochondrial GDP binding were decreased in brown adipose tissue of mice treated chronically with corticosterone. These changes occurred both in corticosterone-treated mice fed ad libitum and in treated mice pair-fed to control animals. Although the dietary stimulation of brown-adipose-tissue thermogenesis was suppressed by corticosterone, the acute response to cold was not affected.

Inhibition by Oxytetracycline of the Development of the Enhanced Response to Noradrenaline in Cold-Acclimated Rats: A New Approach to the Study of Nonshivering Thermogenesis

1971 ◽  
Vol 49 (6) ◽  
pp. 545-553 ◽  
Author(s):  
Jean Himms–Hagen
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Metabolic Response ◽  
Inner Membrane ◽  
Cytochrome Oxidase Activity ◽  
Mitochondrial Inner Membrane ◽  
Brown Adipose

The aim of these experiments was to depress the increased metabolic activity of the brown adipose tissue in the intact rat during acclimation to cold in order to elucidate further the possible thermogenic and endocrine functions of this tissue. The antibiotic oxytetracycline was administered twice daily for 2 weeks to rats living at 4 °C in an attempt to inhibit the proliferation of mitochondria and of mitochondrial inner membrane known to occur in the brown adipose tissue in response to cold; control rats received saline during the same period. Total cytochrome oxidase activity served as an index of the amount of mitochondrial inner membrane in brown adipose tissue, liver, and skeletal muscle. The development of an enhanced calorigenic response to intravenously infused noradrenaline served as an index of the extent of acclimation to cold.Treatment with oxytetracycline inhibited both the cold-induced increase in cytochrome oxidase activity in brown adipose tissue and the cold-induced development of an enhanced calorigenic response to noradrenaline in the intact rats; a direct correlation was noted between the amount of cytochrome oxidase in brown adipose tissue and the size of the metabolic response to noradrenaline of the intact animals. However, the amount of oxygen that could be consumed by the total cytochrome oxidase in the brown adipose tissue was itself too small to account for the increase in oxygen consumption by the rat. Treatment of the rats with oxytetracycline did not alter the cold-induced growth of brown adipose tissue (as judged by the increase in wet weight and the increase in total protein); it also did not alter the cytochrome oxidase activities of liver or skeletal muscle. The effect of oxytetracycline seems, therefore, to be fairly specific for the mitochondria of the most rapidly dividing tissue, the brown adipose tissue. The conclusion is drawn that a protein synthesized in the mitochondria of the brown adipose tissue in response to cold is essential for adaptation to cold.

Evidence that fasting can induce a selective loss of uncoupling protein from brown adipose tissue mitochondria of mice

1986 ◽  
Vol 6 (9) ◽  
pp. 805-810 ◽  
Author(s):  
P. Trayhurn ◽  
G. Jennings
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Uncoupling Protein ◽  
Cytochrome Oxidase Activity ◽  
Selective Loss ◽  
Brown Adipose ◽  
Fasting And Refeeding ◽  
Total Tissue

The effects of fasting and refeeding on the concentration of uncoupling protein in brown adipose tissue mitochondria have been investigated in mice. Fasting mice for 48 h led to a large decrease in the total cytochrome oxidase activity of the interscapular brown fat pad. Mitochondrial GDP binding and the specific mitochondrial concentration of uncoupling protein also fell on fasting. After 24 h refeeding both GDP binding and the mitochondrial concentration of uncoupling protein were normalized, but there was no alteration in the total tissue cytochrome oxidase activity. Fasting appears to induce a selective loss of uncoupling protein from brown adipose tissue mitochondria, which is rapidly reversible on refeeding.

Changes in cytochrome oxidase activity in brown adipose tissue during oestrous cycle in the rat

1998 ◽  
Vol 139 (4) ◽  
pp. 433-437 ◽  
Author(s):  
M Puerta ◽  
M Rocha ◽  
S Gonzalez-Covaleda ◽  
S. McBennett ◽  
J. Andrews
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Oestrous Cycle ◽  
Cytochrome Oxidase Activity ◽  
Brown Adipose

Nonshivering thermogenesis and the thermogenic capacity of brown fat in fasted and/or refed mice

1988 ◽  
Vol 254 (1) ◽  
pp. R11-R16 ◽  
Author(s):  
P. Trayhurn ◽  
G. Jennings
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Uncoupling Protein ◽  
Nonshivering Thermogenesis ◽  
Interscapular Brown Adipose Tissue ◽  
Cytochrome Oxidase Activity ◽  
Brown Adipose ◽  
Thermogenic Capacity

The effects of fasting and refeeding on nonshivering thermogenesis and the properties of brown adipose tissue have been investigated in mice. Fasting for 48 h led to a substantial reduction in the capacity for nonshivering thermogenesis, and there was no recovery of thermogenic capacity during the first 5 days of refeeding. A period of 10-15 days of refeeding was required for full restoration of thermogenic capacity. The mice were hyperphagic during the first 6 days of refeeding, but body weight was recovered after 24 h. The amount of interscapular brown adipose tissue decreased substantially on fasting, but it recovered 24 h after the initiation of refeeding. Cytochrome oxidase activity, the level of mitochondrial GDP binding, and the specific mitochondrial concentration of uncoupling protein in brown adipose tissue were each reduced by fasting. Although both GDP binding and the specific concentration of uncoupling protein rapidly returned to normal on refeeding, the activity of cytochrome oxidase was not normalized until 10 days after the end of the fast. These results indicate that a prolonged period of refeeding is required for the recovery in the capacity for nonshivering thermogenesis following a fast, a similar time course being evident for the recovery of cytochrome oxidase activity in brown adipose tissue. It is suggested that the fasting-induced reduction in the capacity for nonshivering thermogenesis is linked primarily to a loss of mitochondria from brown adipose tissue and that the normalization of thermogenic capacity is dependent on the restoration of mitochondrial mass.

Sign in / Sign up

Export Citation Format

Share Document