Nonshivering thermogenesis in the African lesser bushbaby, Galago moholi

The Zucker obese rat is characterized by decreased capacity for diet-induced and for nonshivering thermogenesis. This decrease is due, in large part, to reduced thermogenesis in depots of brown adipose tissue, a major source of heat production in rats. Adrenalectomy retards the weight gain observed in the obese rats and also normalizes brown fat guanosine 5'-diphosphate (GDP) binding, an in vitro measure of brown fat thermogenic capacity. This study examined the effect of adrenalectomy on brown fat blood flow, an in vivo measure of the tissue's function, and on norepinephrine-induced O2 consumption (NST) of 11-wk-old obese (fa/fa) and lean (Fa/?) rats. Adrenalectomy had little effect on weight gain, NST, or norepinephrine-stimulated blood flow to brown fat in lean rats. However, adrenalectomy produced profound changes in the obese animals, preventing the weight gain normally occurring in the obese rats and normalizing both NST capacity and norepinephrine-stimulated blood flow to brown fat. These findings provide further support for the importance of brown fat thermogenesis and glucocorticoids in modulating the obesity of the Zucker rat.

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Corticosterone decreases nonshivering thermogenesis and increases lipid storage in brown adipose tissue

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.268.1.r183 ◽

1995 ◽

Vol 268 (1) ◽

pp. R183-R191 ◽

Cited By ~ 13

Author(s):

A. M. Strack ◽

M. J. Bradbury ◽

M. F. Dallman

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Glucocorticoid Receptors ◽

Uncoupling Protein ◽

Lipid Storage ◽

Scatchard Analysis ◽

Nonshivering Thermogenesis ◽

Diurnal Range ◽

Brown Adipose ◽

Intact Rats

Brown adipose tissue (BAT) contains glucocorticoid receptors; glucocorticoids are required for maintaining differentiated BAT in culture. These studies were performed to determine the effects of corticosterone on BAT thermogenic function and lipid storage. Rats were adrenalectomized and given subcutaneous corticosterone pellets in concentrations that maintained plasma corticosterone constant across the range of 0-20 micrograms/dl or were sham adrenalectomized. All variables were examined 5 days after surgery and corticosterone replacement. Measures of BAT function-thermogenic capacity [guanosine 5'-diphosphate (GDP) binding and uncoupling protein (UCP; a BAT-specific thermogenic protein)] and storage (BAT wet wt, protein, and DNA levels) were made. Plasma hormones (corticosterone, adrenocorticotropic hormone, insulin, 3,3',5-triiodothyronine, and thyroxine were measured. Corticosterone significantly affected BAT thermogenic measures: UCP content and binding of GDP to BAT mitochondria decreased with increasing corticosterone; GDP binding characteristics in BAT from similarly prepared rats examined by Scatchard analysis showed that maximum binding (Bmax) and dissociation constant (Kd) decreased with increasing corticosterone dose. BAT DNA was increased by adrenalectomy and maintained at intact levels with all doses of corticosterone; BAT lipid storage increased dramatically at corticosterone values higher than the daily mean level in intact rats. Histologically, the number and size of lipid droplets within BAT adipocytes increased markedly with increased corticosterone. White adipose depots were more sensitive to circulating corticosterone concentrations than were BAT depots and increased in weight at levels of corticosterone that were at or below the daily mean level of intact rats. We conclude that, within its diurnal range of concentration corticosterone acts to inhibit nonshivering thermogenesis and increase lipid storage.(ABSTRACT TRUNCATED AT 250 WORDS)

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Tissue-Specific Expression of Cytochrome c Oxidase Isoforms and Role in Nonshivering Thermogenesis

Frontiers of Cellular Bioenergetics ◽

10.1007/978-1-4615-4843-0_24 ◽

1999 ◽

pp. 621-633

Author(s):

Bernhard Kadenbach ◽

Viola Frank ◽

Dietmar Linder ◽

Susanne Arnold ◽

Stefan Exner ◽

...

Keyword(s):

Cytochrome C ◽

Cytochrome C Oxidase ◽

Nonshivering Thermogenesis ◽

Specific Expression ◽

Tissue Specific ◽

Tissue Specific Expression

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NEUROHUMORAL REGULATION OF NONSHIVERING THERMOGENESIS IN MAMMALS

Strategies in Cold ◽

10.1016/b978-0-12-734550-5.50023-5 ◽

1978 ◽

pp. 619-653 ◽

Cited By ~ 6

Author(s):

B.A. Horwitz

Keyword(s):

Nonshivering Thermogenesis ◽

Neurohumoral Regulation

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IMPORTANCE OF BLOOD FLOW TO CALORIGENIC ORGANS IN NONSHIVERING THERMOGENESIS INDUCED BY NOREPINEPHRINE

Contributions to Thermal Physiology ◽

10.1016/b978-0-08-027354-9.50089-2 ◽

1981 ◽

pp. 435-437

Author(s):

T. NAGASAKA ◽

K. HIRATA ◽

Y. SUGANO ◽

H. SHIBATA

Keyword(s):

Blood Flow ◽

Nonshivering Thermogenesis

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Responses of cold- and warm-adapted dogs to infused norepinephrine and acute body cooling

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1965.209.1.227 ◽

1965 ◽

Vol 209 (1) ◽

pp. 227-230 ◽

Cited By ~ 13

Author(s):

Tetsuo Nagasaka ◽

Loren D. Carlson

Keyword(s):

Heart Rate ◽

Oxygen Consumption ◽

Cold Exposure ◽

Nonshivering Thermogenesis ◽

Mechanically Ventilated ◽

Cold Adapted ◽

Pentobarbital Sodium ◽

Acute Cold Exposure ◽

Increased Sensitivity ◽

Body Cooling

Oxygen consumption, heart rate, and colonic, pinna, and paw temperatures were recorded continuously in warm-adapted (W-A) and cold-adapted (C-A) dogs anesthetized with pentobarbital sodium (30 mg/kg), paralyzed with Flaxedil (5 mg/kg per hr), and mechanically ventilated. The dogs were infused with norepinephrine (1.25 µg/kg per min) for 20 min at 30 C and after 45 min of acute cold exposure to 5 C. Oxygen consumption of C-A dogs increased with a slight increase in the heart rate during the initial 18–20 min of body cooling. O2 consumption decreased continuously during cold exposure in W-A dogs. Calorigenic effects of infused noradrenaline were similar in C-A and W-A dogs at 30 C and 5 C. Heart rate increased in W-A dogs at 30 and 5 C. These results show that nonshivering thermogenesis is well developed by cold acclimation in dogs, and suggest that the increase may be due to an increase in noradrenaline in blood rather than to increased sensitivity of the animals to the calorigenic effects of noradrenaline.

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