Interrelationships among activity, food intake and weight gain in genetically obese and lean Zucker rats

Enns, Melvin P.; Wecker, John R.; Grinker, Joel A.

doi:10.1016/0031-9384(82)90175-5

Cited by 11 publications

(3 citation statements)

References 23 publications

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“…Thus the lower temperatures in the Zucker obese rats are unlikely to be related to reduced heat production in skeletal muscle. Previous studies have reached differing conclusions concerning the amount of bodily activity in Zucker obese rats, with the variability due to different measuring procedures being noted [16,[31][32][33]. Taken together with these previous studies, our findings suggest that BAT thermogenesis is reduced in the Zucker obese rats.…”

Section: Zucker Obese (Fa/fa) Rats Have Lower Bat Brain and Body Temperatures In Comparison With Lean Controlssupporting

confidence: 67%

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Kontos

Menezes

Ootsuka

et al. 2013

Physiology & Behavior

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In Sprague-Dawley rats, brown adipose tissue (BAT) thermogenesis occurs in an episodic ultradian manner (BAT on-periods) as part of the basic rest-activity cycle (BRAC). Eating occurs approximately 15min after the onset of BAT on-periods. Zucker obese (fa/fa) rats eat larger less frequent meals than control rats. In chronically instrumented conscious unrestrained Zucker obese rats we examined ultradian fluctuations in BAT, body and brain temperatures, and the relation between BAT temperature and eating. The interval between BAT temperature peaks for the 12hour dark phase was 121±3 (mean±SE) min for Zucker obese rats and 91±3min for control lean rats (p<0.01). Corresponding values for the light phase were 148±6 and 118±4min (p<0.01). Mean BAT and body temperatures were lower in Zucker obese rats, in comparison with lean controls, during both BAT on-periods and BAT off-periods. Mean brain temperatures were lower during BAT off-periods. Amplitudes of the BRAC-related increases in all 3 temperatures were greater in the Zucker obese rats. Meal onset in Zucker obese rats commenced 15±1min after the onset of a BAT on-period, not significantly different for the delay observed in lean control rats (18±1min, p>0.05). Thus periods between eating are increased in the Zucker obese rats, but the action of leptin, absent in these animals, is not crucial for the timing of eating in relation to increases in BAT and body temperature. Lack of the normal excitatory action of leptin on brain-regulated BAT sympathetic discharge could also contribute to lower BAT thermogenesis in Zucker obese rats.

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Section: Zucker Obese (Fa/fa) Rats Have Lower Bat Brain and Body Temperatures In Comparison With Lean Controlssupporting

confidence: 67%

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Kontos

Menezes

Ootsuka

et al. 2013

Physiology & Behavior

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“…On the other hand, denervation (37) and hypokinesia (hindlimb suspension) (11) decrease SV lactate transport as well as MCT1 and MCT4 expression (37). Interestingly, a series of data shows the decreased spontaneous activity in obese compared with lean Zucker rats (12,16,36). Indeed, when fed ad libitum, obese Zucker rats appear to be less active than lean ones (16).…”

Section: Discussionmentioning

confidence: 99%

Impaired sarcolemmal vesicle lactate uptake and skeletal muscle MCT1 and MCT4 expression in obese Zucker rats

Py¹,

Lambert²,

Perez-Martin³

et al. 2001

American Journal of Physiology-Endocrinology and Metabolism

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The present experiments were undertaken to characterize 1) the hindlimb muscle mass lactate uptake and 2) the expression of monocarboxylate transporter isoforms MCT1 and MCT4, as well as lactate dehydrogenase (LDH) isozyme distribution, in various skeletal muscles of Zucker fa/fa rats taken as a model of insulin resistance-related obesity. Initial lactate uptake at six different concentrations was measured in sarcolemmal vesicles (SV) by use of L-[U-(14)C]lactate. Compared with controls, the maximal rate of lactate uptake and affinity were decreased in SV of Zucker rats (approximately 30%) in which MCT4 content was significantly decreased (P < 0.05). MCT4 expression was decreased in soleus, extensor digitorum longus, and red tibialis anterior (RTA; P < 0.05), but not in white tibialis anterior, whereas MCT1 expression was decreased only in RTA of Zucker rats (P < 0.05). Obesity led to a shift toward type M-LDH isozyme in mixed muscles. We conclude that obesity leads to changes in muscular MCT1 and MCT4 expression, which, when associated with LDH isozyme redistribution, may contribute to the hyperlactatemia noted in insulin resistance.

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“…This is indicated by findings that young ob/ob mice begin to display low levels of activity before the development of their characteristic obesity (83). Similarly, running wheel activity was consistently lower in Zucker obese (ja/fa) rats compared with their lean littermates from the time of weaning to 6 months of age (84,85). These findings suggest that even gradual increases in body weight affect activity levels in those predisposed to obesity.…”

Section: Activity As a Function Of Strainmentioning

confidence: 96%

Determinants Affecting Physical Activity Levels In Animal Models¹

Tou

Wade

2002

Exp Biol Med (Maywood)

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Interrelationships among activity, food intake and weight gain in genetically obese and lean Zucker rats

Cited by 11 publications

References 23 publications

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Impaired sarcolemmal vesicle lactate uptake and skeletal muscle MCT1 and MCT4 expression in obese Zucker rats

Determinants Affecting Physical Activity Levels In Animal Models¹

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Interrelationships among activity, food intake and weight gain in genetically obese and lean Zucker rats

Cited by 11 publications

References 23 publications

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Brown adipose tissue thermogenesis precedes food intake in genetically obese Zucker (fa/fa) rats

Impaired sarcolemmal vesicle lactate uptake and skeletal muscle MCT1 and MCT4 expression in obese Zucker rats

Determinants Affecting Physical Activity Levels In Animal Models1

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Determinants Affecting Physical Activity Levels In Animal Models¹