Energy balance in pregnant hamsters: a role for voluntary exercise?

1993 ◽  
Vol 265 (3) ◽  
pp. R563-R567 ◽  
Author(s):  
A. J. Bhatia ◽  
G. N. Wade
Keyword(s):  
Energy Balance ◽  
Food Intake ◽  
Body Fat ◽  
Voluntary Exercise ◽  
Running Wheel ◽  
Abrupt Decrease ◽  
Syrian Hamsters ◽  
Body Fat Content ◽  
Wheel Activity ◽  
Induced Changes

During pregnancy or after experimental manipulations of ovarian hormone levels, Syrian hamsters exhibit changes in energy balance and body fat content without modifying their food intake. The present experiments determined whether fluctuations in voluntary exercise play a role in these changes in energy balance, as they appear to do in other species. As expected, pregnant hamsters maintained a constant level of food intake and lost approximately 40% of their body fat. These animals did not show the abrupt decrease in activity after mating that is seen in rats. Instead, they maintained their high, premating level of running wheel activity until the last 3 days of pregnancy. Similarly, ovariectomy and replacement therapy with estradiol or estradiol+progesterone caused substantial changes in energy balance in the absence of significant changes in food intake or running wheel activity. These findings indicate that, unlike rats, Syrian hamsters do not exhibit substantial changes in voluntary exercise during pregnancy or in response to manipulations of ovarian steroid levels. Therefore, neither changes in food intake nor in voluntary exercise play any important role in the pregnancy- or steroid-induced changes in energy balance in Syrian hamsters.

Dorsomedial hypothalamic corticotropin-releasing factor mediation of exercise-induced anorexia

2005 ◽  
Vol 288 (6) ◽  
pp. R1800-R1805 ◽  
Author(s):  
Maiko Kawaguchi ◽  
Karen A. Scott ◽  
Timothy H. Moran ◽  
Sheng Bi
Keyword(s):  
Gene Expression ◽  
Body Weight ◽  
Food Intake ◽  
Mrna Expression ◽  
Critical Role ◽  
Voluntary Exercise ◽  
Running Wheel ◽  
Exercise Induced ◽  
Running Wheels ◽  
Induced Changes

Running wheel access and resulting voluntary exercise alter food intake and reduce body weight. The neural mechanisms underlying these effects are unclear. In this study, we first assessed the effects of 7 days of running wheel access on food intake, body weight, and hypothalamic gene expression. We demonstrate that running wheel access significantly decreases food intake and body weight and results in a significant elevation of CRF mRNA expression in the dorsomedial hypothalamus (DMH) but not the paraventricular nucleus. Seven-day running wheel access also results in elevated arcuate nucleus and DMH neuropeptide Y gene expression. To assess a potential role for elevated DMH CRF activity in the activity-induced changes in food intake and body weight, we compared changes in food intake, body weight, and hypothalamic gene expression in rats receiving intracerebroventricular (ICV) CRF antagonist α-helical CRF or vehicle with or without access to running wheels. During a 4-day period of running wheel access, we found that exercise-induced reductions of food intake and body weight were significantly attenuated by ICV injection of the CRF antagonist. The effect on food intake was specific to a blockade of activity-induced changes in meal size. Central CRF antagonist injection further increased DMH CRF mRNA expression in exercised rats. Together, these data suggest that DMH CRF play a critical role in the anorexia resulting from increased voluntary exercise.

Metabolic control of food intake and estrous cycles in Syrian hamsters. I. Plasma insulin and leptin

2000 ◽  
Vol 278 (2) ◽  
pp. R476-R485 ◽  
Author(s):  
Jill E. Schneider ◽  
Robert M. Blum ◽  
George N. Wade
Keyword(s):  
Food Intake ◽  
Body Fat ◽  
Plasma Concentrations ◽  
Fat Content ◽  
Syrian Hamsters ◽  
Body Fat Content ◽  
Control Food ◽  
Control Food Intake ◽  
Plasma Leptin ◽  
Reproductive Processes

The “adipostat hypothesis” refers to the idea that circulating hormone concentrations reflect levels of body adiposity and act as signals to control food intake and reproduction. Implicit in the adipostatic hypothesis are the following two assumptions: 1) plasma levels of adipostatic hormones accurately reflect body fat content and 2) decreased plasma concentrations of adipostatic hormones necessarily result in increased food intake and inhibited reproductive processes. The present experiments are designed to test these assumptions. Fat and lean Syrian hamsters were either fasted for 12, 24, 36, or 48 h or allowed ad libitum access to food. Contrary to the first assumption, plasma leptin and insulin levels in fat hamsters dropped dramatically by 12 h after the start of a fast, with no significant change in body fat content and no postfast hyperphagia. Lean hamsters showed anestrus after a 48-h fast but not after a 24-h fast. Contrary to the second assumption of the lipostatic hypothesis, lean hamsters fasted for 24 h and then refed for the next 24 h had leptin levels that were not significantly elevated compared with those of 48-h-fasted hamsters. Thus, in adult female Syrian hamsters, plasma leptin concentrations do not accurately reflect body fat content under all conditions; normal estrous cyclicity does not necessarily require plasma leptin concentrations higher than those of fasted hamsters; and decreased plasma leptin levels do not result in increased food intake.

A note on the effects of body fatness and level of food intake on the rate of fat loss in lactating ewes

1982 ◽  
Vol 34 (3) ◽  
pp. 355-357 ◽  
Author(s):  
R. T. Cowan ◽  
J. J. Robinson ◽  
I. McDonald
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Body Fat ◽  
Metabolizable Energy ◽  
Body Fatness ◽  
Fat Loss ◽  
Body Fat Content ◽  
Metabolizable Energy Intake ◽  
Image Position ◽  
The Relationship

ABSTRACTData from three comparative slaughter experiments involving a total of 73 ewes were used to study the influence of body fat content at the start of lactation (X1 kg) and of metabolizable energy intake (X2, MJ/day), on the rate of loss of body fat by lactating ewes over the first 6 weeks of lactation (Y, g/day). The relationship was described by the equation:Thus the rate of fat loss was greater for ewes with higher initial fat contents, but the differential became less as metabolizable energy intake increased. Since increases in body fatness depress food intake it was not possible to prevent loss of body fat during early lactation in fat ewes given high concentrate diets ad libitum. The likely response in milk yield to increase in body fatness at parturition is therefore strongly dependent on the relative levels of body fatness and metabolizable energy intake. The value of any improvement in condition of the ewe at parturition may be considerable when metabolizable energy intake during lactation is low but much less when it is expected to be high.

Insulin-induced anestrus in Syrian hamsters

1991 ◽  
Vol 260 (1) ◽  
pp. R148-R152 ◽  
Author(s):  
G. N. Wade ◽  
J. E. Schneider ◽  
M. I. Friedman
Keyword(s):  
Food Intake ◽  
Body Fat ◽  
Significant Inhibition ◽  
Acid Oxidation ◽  
Estrous Cycles ◽  
Syrian Hamsters ◽  
Metabolic Fuel ◽  
Energy Demands ◽  
Estrous Cyclicity ◽  
Ad Libitum

In Syrian hamsters, reproduction is sensitive to the availability of metabolic fuels. Estrous cycles can be interrupted by brief periods of food deprivation, by pharmacological inhibition of glycolysis and fatty acid oxidation, or by increasing energy demands for thermoregulation. We predicted that manipulations that divert an excessive portion of the metabolic fuel supply into storage also should inhibit reproduction. Redirection of metabolic fuels from oxidation to storage was accomplished by treatment with protamine zinc insulin suspension (PZI). Syrian hamsters treated with PZI and fed ad libitum increased their food intake by approximately equal to 40% and body fat stores, but there was no effect on estrous cycles. When PZI-treated hamsters were limited to approximately equal to 110% of their preinjection food intake, they still fattened, and there was a significant inhibition of estrous cyclicity. Thus, in the absence of overeating, PZI-enhanced energy storage may lead to a shortage of oxidizable metabolic fuels with the result that reproduction is inhibited in favor of processes essential for survival (e.g., cellular maintenance, thermoregulation). It is unlikely that insulin-induced anestrus is due to actions of PZI unrelated to metabolic fuel partitioning, because the hormone had no effects on estrous cyclicity in ad libitum-fed hamsters. These findings are inconsistent with the hypothesis that nutritional infertility is due to the failure to maintain a minimum body fat content and raise the possibility that the infertility associated with some types of obesity could be due in part to a disorder of macronutrient partitioning.

Energy balance and brown adipose tissue thermogenesis during pregnancy in Syrian hamsters

1986 ◽  
Vol 250 (5) ◽  
pp. R845-R850 ◽  
Author(s):  
G. N. Wade ◽  
G. Jennings ◽  
P. Trayhurn
Keyword(s):  
Adipose Tissue ◽  
Energy Balance ◽  
Food Intake ◽  
Brown Adipose Tissue ◽  
Interscapular Brown Adipose Tissue ◽  
Estrous Cycles ◽  
Syrian Hamsters ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis ◽  
Circulating Levels

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.

Glucocorticoids reverse leptin effects on food intake and body fat in mice without increasing NPY mRNA

1999 ◽  
Vol 277 (4) ◽  
pp. E708-E716 ◽  
Author(s):  
Joel M. Solano ◽  
Lauren Jacobson
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Body Fat ◽  
Mrna Levels ◽  
Plasma Insulin Levels ◽  
Significant Attenuation ◽  
Induced Changes ◽  
Leptin Expression ◽  
Stimulation Of

Glucocorticoid stimulation of appetite and leptin expression conflicts with leptin inhibition of food intake and suggests that glucocorticoids reduce sensitivity to leptin. To determine if glucocorticoids impair feeding and metabolic responses to leptin, we measured leptin-induced changes in food intake, body weight, hormones, carcass fat, and hypothalamic neuropeptide Y (NPY) mRNA in adrenalectomized mice with and without corticosterone replacement. Leptin infusion (0.5 μg/h) significantly decreased food intake and body weight in adrenalectomized mice. Corticosterone replacement approximating normal 24-h mean levels restored food intake but did not permit weight gain equivalent to PBS-infused controls. Corticosterone levels comparable to stress-induced production completely reversed leptin-induced reductions in weight gain and body fat, despite significant attenuation by leptin of corticosterone-induced increases in plasma insulin levels. Glucocorticoid replacement increased food intake without reversing leptin inhibition of hypothalamic NPY mRNA levels. We conclude that glucocorticoid levels within the physiological range can interfere with leptin action and that glucocorticoid effects are at least partly independent of NPY.

scholarly journals Body fat content, composition and distribution in Landrace and Iberian finishing pigs given ad libitum maize- and acorn-sorghum-maize-based diets

2003 ◽  
Vol 77 (2) ◽  
pp. 215-224 ◽  
Author(s):  
J. Morales ◽  
M.D. Baucells ◽  
J.F. Pérez ◽  
J. Mourot ◽  
J. Gasa
Keyword(s):  
Food Intake ◽  
Body Fat ◽  
Live Weight ◽  
Intramuscular Fat ◽  
Fat Content ◽  
Backfat Thickness ◽  
Lipogenic Enzyme ◽  
Body Fat Content ◽  
Fat Composition ◽  
Intramuscular Fat Content

AbstractWe aimed to determine whether the dietary carbohydrate source altered body fat composition and distribution in finishing lean (Landrace) and obese (Iberian) swine. To this end, twenty-four finishing castrated male pigs (12 Iberian and 12 Landrace; 108 kg live weight) were offered two diets differing in the main carbohydrates source, maize (diet M) or acorn-sorghum-maize (diet A). Diets were formulated to have the same nutrient content, except for carbohydrate fractions: diet M contained higher amount of starch (537 v. 389 g/kg) but less non-starch polysaccharides (118 v. 148 g/ kg) than diet A. At an average weight of 133 kg live weight pigs were slaughtered and their carcasses were sampled to study lipogenesis, backfat and intramuscular fat composition. Iberian pigs showed a higher voluntary food intake than Landrace pigs (3·6 v. 2·4 kg/day; P < 0·001) but no significant differences in the daily weight gain. Diet M tended to promote the highest food intake (P = 0·09). Iberian pigs showed higher (P < 0·01) lipogenic enzyme activities, backfat thickness (71·7 v. 31·9 mm) and intramuscular fat content (40 to 95 g/kg fresh muscle) than Landrace pigs, which was associated with their higher food intake. Furthermore, fat depots from Iberian pigs had higher (P < 0·001) monounsaturated fatty acids (MUFA) and lower (P < 0·05) polyunsaturated (PUFA) proportions than those from Landrace pigs. The backfat thickness of pigs given diet M tended to be higher (P = 0·07) than that of pigs given diet A, without differences in the intramuscular fat content. The higher backfat thickness found for diet M was correlated with a lower PUFA proportion in diet than for diet A (P < 0·001). We conclude that body fat content, composition and lipogenic enzyme activities are markedly influenced by the animal breed and to a lesser extent by dietary characteristics.

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