Decreased brown adipose tissue thermogenic activity following a reduction in brain serotonin by intraventricular p-chlorophenylalanine

1987 ◽  
Vol 7 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Nigel J. Fuller ◽  
Dorothy M. Stirling ◽  
Stephen Dunnett ◽  
Gavin P. Reynolds ◽  
Margaret Ashwell

The effects of reducing brain serotonin (5-HT) levels by means of intracerebral-ventricular injections of the tryptophan antagonist p-chlorophenylalanine (PCPA) were investigated in male rats. Six days after the operation, PCPA-treated rats, either fed ad libitum or pair-fed to the food intake of control rats, showed decreased thermogenic activity and capacity in their interscapular brown adipose tissue (BAT) and also increased fat storage in their white adipose tissue (WAT). These results indicate that serotonergic synapses might play a regulatory role in the sympathetic control of BAT thermogenesis and in the rate of WAT deposition (by an as yet unidentified mechanism), in addition to their well established role in controlling food intake.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. Van Schaik ◽  
C. Kettle ◽  
R. Green ◽  
W. Sievers ◽  
M. W. Hale ◽  
...  

AbstractThe role of central orexin in the sympathetic control of interscapular brown adipose tissue (iBAT) thermogenesis has been established in rodents. Stimulatory doses of caffeine activate orexin positive neurons in the lateral hypothalamus, a region of the brain implicated in stimulating BAT thermogenesis. This study tests the hypothesis that central administration of caffeine is sufficient to activate BAT. Low doses of caffeine administered either systemically (intravenous [IV]; 10 mg/kg) and centrally (intracerebroventricular [ICV]; 5–10 μg) increases BAT thermogenesis, in anaesthetised (1.5 g/kg urethane, IV) free breathing male rats. Cardiovascular function was monitored via an indwelling intra-arterial cannula and exhibited no response to the caffeine. Core temperature did not significantly differ after administration of caffeine via either route of administration. Caffeine administered both IV and ICV increased neuronal activity, as measured by c-Fos-immunoreactivity within subregions of the hypothalamic area, previously implicated in regulating BAT thermogenesis. Significantly, there appears to be no neural anxiety response to the low dose of caffeine as indicated by no change in activity in the basolateral amygdala. Having measured the physiological correlate of thermogenesis (heat production) we have not measured indirect molecular correlates of BAT activation. Nevertheless, our results demonstrate that caffeine, at stimulatory doses, acting via the central nervous system can increase thermogenesis, without adverse cardio-dynamic impact.


1988 ◽  
Vol 255 (5) ◽  
pp. E708-E715 ◽  
Author(s):  
S. W. Corbett ◽  
L. N. Kaufman ◽  
R. E. Keesey

The role of brown adipose tissue in the thermogenic response to lateral hypothalamic (LH) lesions was investigated. Interscapular brown adipose tissue (IBAT) temperatures were measured during the hours following bilateral electrolytic LH lesions in male rats sedated with pentobarbital sodium. Local temperature changes were also recorded from skin and colonic sites. Consistent with the view that brown adipose tissue plays a primary role in the hyperthermia produced by LH lesions, IBAT depot temperature rose before, at a faster rate, and to a higher level than the other sites. In two subsequent experiments, oxygen consumption, activity, and core temperature were monitored in freely moving male rats with LH lesions, both in warm (25 degrees C) and cold (5 degrees C) environments. The results of these experiments provide some support for the view that LH lesions produce an increase in the regulated level of body temperature. This hyperthermic and hypermetabolic state seems to be mediated, in part, by brown fat thermogenesis and may represent a general increase in sympathetic nervous activity induced by the lesion.


1993 ◽  
Vol 295 (1) ◽  
pp. 171-176 ◽  
Author(s):  
M C Sugden ◽  
M J Holness

Glucose utilization indices (GUI values) and rates of fatty acid synthesis in interscapular brown adipose tissue (IBAT) varied during the diurnal cycle in virgin and late-pregnant rats permitted unrestricted access to food. In virgin rats, peak GUI values and lipogenic rates were observed at the end of the dark (feeding) phase, but were not sustained during the light phase. Whereas peak GUI values were comparable with those observed during re-feeding after 24 h starvation, maximum rates of IBAT fatty acid synthesis in virgin rats during the diurnal cycle were only approx. 25% of those measured during re-feeding after 24 h starvation. Despite hyperphagia, GUI values during the diurnal cycle in late-pregnant rats fed ad libitum were generally lower than those of age-matched virgin controls. The percentage of pyruvate dehydrogenase complex present in the active form (PDHa) was also significantly decreased. Suppression of GUI and PDHa was not parallelled by suppression of fatty acid synthesis. IBAT GUI values in late-pregnant rats during chow re-feeding ad libitum after 24 h starvation were only 25% of those of corresponding virgin controls, and stimulation of fatty acid synthesis was also dramatically attenuated. The suppression of IBAT GUI values after re-feeding in pregnancy was not due to depletion of GLUT 4 protein. The results are discussed in relation to the importance of glucose as a precursor for fatty acid synthesis in IBAT.


1992 ◽  
Vol 126 (5) ◽  
pp. 434-437 ◽  
Author(s):  
María Abelenda ◽  
Maria Paz Nava ◽  
Alberto Fernández ◽  
María Luisa Puerta

The participation of sexual hormones in body weight regulation is partly accomplished by altering food intake. Nonetheless, female sexual hormones also alter brown adipose tissue thermogenesis in females. This study was aimed to find out if male hormones could alter brown adipose tissue thermogenesis in male rats. Testosterone was administered by means of Silastic capsules in adult male rats acclimated either at 28°C (thermoneutrality) or at 6°C (cold), treatment lasting 15 days. Food intake and body weight gain were reduced by hormonal treatment. However, brown adipose tissue mass, protein content, mitochondrial mass and GDP-binding were unchanged at both environmental temperatures. Accordingly, testosterone participation in body weight regulation is thought to be carried out without altering brown adipose tissue thermogenesis. A reduction in the weight of the sex accessory glands was also observed after cold acclimation.


1997 ◽  
Vol 272 (3) ◽  
pp. E453-E460 ◽  
Author(s):  
C. Duchamp ◽  
K. A. Burton ◽  
A. Geloen ◽  
M. J. Dauncey

The possible involvement of locally produced insulin-like growth factor I (IGF-I) in the cold-induced hyperplasia of interscapular brown adipose tissue (BAT) was investigated in 2-, 4-, and 7-day cold-exposed (CE, 4 degrees C) rats by measuring BAT IGF-I expression at a time when extensive BAT cell proliferation occurs. By comparison with thermoneutral (25 degrees C) controls, plasma IGF-I decreased in CE rats despite an increased food intake, whereas BAT IGF-I peptide increased markedly to peak after 4 days at 4 degrees C. The ratio of class 1 to class 2 IGF-I mRNA was much higher in BAT than in liver. BAT IGF-I mRNA levels per unit weight total RNA doubled after 2 days at 4 degrees C but decreased thereafter to the level in controls. Upregulation of BAT IGF-I mRNA also occurred in CE rats with a food intake restricted to the level of controls. The transient cold-induced upregulation of BAT IGF-I (per unit weight total RNA) suggests that IGF-I plays a role in the early cold-induced BAT hyperplasia that occurs in vivo.


2016 ◽  
Vol 66 (2) ◽  
pp. 201-217 ◽  
Author(s):  
Wen-rong Gao ◽  
Wan-long Zhu ◽  
Fang-yan Ye ◽  
Mu-lin Zuo ◽  
Zheng-kun Wang

Physiological adjustments are important strategies for small mammals in response to variation in food availability. To determine the physiological mechanisms affected by food restriction and refeeding, tree shrews were restricted to 85% of initial food intake for 4 weeks and refedad libitumfor another 4 weeks. Changes in food intake, body mass, thermogenesis, body composition, mitochondrial cytochromecoxidase activity, uncoupling protein-1 content in brown adipose tissue and serum leptin levels were measured. The results showed that body mass, body fat mass and serum leptin levels significantly decreased in food restricted tree shrews, and increased when the restriction ended, showing a short “compensatory growth” rather than over-weight or obesity compared withad libitumcontrols. Resting metabolic rate, non-shivering thermogenesis, brown adipose tissue mass (mg), and uncoupling protein-1 content decreased significantly in response to food restriction, and returned to the control levels after the animals were refedad libitum, while the brown adipose tissue mass (%) and cytochromecoxidase activity remained stable during food restriction and refeeding. Food intake increased shortly after refeeding, which perhaps contributed to the rapid regaining of body mass. These results suggest thatTupaia belangerican adjust the status of its physiology integratively to cope with the lack of food by means of decreasing body mass, thermogenesis and serum leptin levels. Leptin may act as a starvation signal to predominantly mediate the reduction in body mass and energy expenditure.


1986 ◽  
Vol 250 (5) ◽  
pp. R845-R850 ◽  
Author(s):  
G. N. Wade ◽  
G. Jennings ◽  
P. Trayhurn

Energy balance and brown adipose tissue thermogenesis were examined during pregnancy in Syrian hamsters (Mesocricetus auratus). Neither estrous cycles nor pregnancy had any effect on food intake, but both were accompanied by significant changes in body weight. Despite their substantial weight gains (attributable to growth of fetuses and placentas), pregnant hamsters actually lost a mean of 48 kJ in carcass energy, whereas unmated controls gained 98 kJ over the same 15 days. During pregnancy hamsters exhibited an increase in protein deposition (almost entirely in the fetuses and placentas), but they lost nearly 40% of their body lipid. An apparent increase in energy expenditure occurred despite a highly significant decrease in brown adipose tissue thermogenesis during pregnancy. By day 15 of pregnancy (within 13 h of expected parturition) there were substantial decreases in interscapular brown adipose tissue weight (-59%), protein content (-54%), and cytochrome-c oxidase activity (-69%). These changes in brown adipose tissue were evident by day 4 of pregnancy and persisted through lactation. It is suggested that this suppression of brown adipose tissue function is due to increased circulating levels of prolactin and subsequently to the nutritional stress of conceptus growth in the absence of an increase in food intake.


1985 ◽  
Vol 63 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Akihiro Kuroshima ◽  
Takehiro Yahata

To determine the role of the nutritional state in nonshivering thermogenesis during cold adaptation, cold adaptability was compared between cold-adapted (5 °C for 4–5 weeks) rats fed ad libitum and cold-adapted rats pair fed with warm controls having the same food intake. Cold-adapted pair-fed rats suffered a significant loss in body weight during cold exposure. However, brown adipose tissue (BAT) in both cold-adapted ad libitum fed and cold-adapted pair-fed rats was enlarged to the same extent as compared with that in control rats. Fat-free dry matter in BAT also increased in cold-adapted ad libitum fed and cold-adapted pair-fed rats to the same extent. Cold tolerance as assessed by the change in the colonic temperature at −5 °C was improved relative to control rats and was the same for cold-adapted ad libitum fed and cold-adapted pair-fed rats. Nonshivering thermogenesis as estimated by the noradrenaline-induced increase in oxygen consumption was significantly greater in the cold-exposed rats and there was no significant difference between cold-adapted ad libitum fed and cold-adapted pair-fed rats. These results suggest that an improved cold tolerance by means of nonshivering thermogenesis in brown adipose tissue is closely related to the low temperature itself but not the increased food intake which occurred in the cold.


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